Alveolar echinococcosis: from a deadly disease to a well-controlled infection. Relative survival and economic analysis in Switzerland over the last 35 years.

BACKGROUND/AIMS: Alveolar echinococcosis (AE) is a serious liver disease. The aim of this study was to explore the long-term prognosis of AE patients, the burden of this disease in Switzerland and the cost-effectiveness of treatment. METHODS: Relative survival analysis was undertaken using a national database with 329 patient records. 155 representative cases had sufficient details regarding treatment costs and patient outcome to estimate the financial implications and treatment costs of AE. RESULTS: For an average 54-year-old patient diagnosed with AE in 1970 the life expectancy was estimated to be reduced by 18.2 and 21.3 years for men and women, respectively. By 2005 this was reduced to approximately 3.5 and 2.6 years, respectively. Patients undergoing radical surgery had a better outcome, whereas the older patients had a poorer prognosis than the younger patients. Costs amount to approximately Euro108,762 per patient. Assuming the improved life expectancy of AE patients is due to modern treatment the cost per disability-adjusted life years (DALY) saved is approximately Euro6,032. CONCLUSIONS: Current treatments have substantially improved the prognosis of AE patients compared to the 1970s. The cost per DALY saved is low compared to the average national annual income. Hence, AE treatment is highly cost-effective in Switzerland.

Relative survival of Escherichia coli and Salmonella typhimurium in a tropical estuary

Microcosm studies have been carried out to find out the relative survival of Escherichia coli and Salmonella typhimurium in a tropical estuary. Survival has been assessed in relation to the important self-purifying parameters such as biotic factors contained in the estuarine water, toxicity due to the dissolved organic and antibiotic substances in the water and the sunlight. The results revealed that sunlight is the most important inactivating factor on the survival of E. coli and S. typhimurium in the estuarine water. While the biological factors contained in the estuarine water such as protozoans and bacteriophages also exerted considerable inactivation of these organisms, the composition of the water with all its dissolved organic and inorganic substances was not damaging to the test organisms. Results also indicated better survival capacity of E. coli cells under all test conditions when compared to S. typhimurium

Alveolar echinococcosis: from a deadly disease to a well-controlled infection. Relative survival and economic analysis in Switzerland over the last 35 years

BACKGROUND/AIMS: Alveolar echinococcosis (AE) is a serious liver disease. The aim of this study was to explore the long-term prognosis of AE patients, the burden of this disease in Switzerland and the cost-effectiveness of treatment. METHODS: Relative survival analysis was undertaken using a national database with 329 patient records. 155 representative cases had sufficient details regarding treatment costs and patient outcome to estimate the financial implications and treatment costs of AE. RESULTS: For an average 54-year-old patient diagnosed with AE in 1970 the life expectancy was estimated to be reduced by 18.2 and 21.3 years for men and women, respectively. By 2005 this was reduced to approximately 3.5 and 2.6 years, respectively. Patients undergoing radical surgery had a better outcome, whereas the older patients had a poorer prognosis than the younger patients. Costs amount to approximately Euro108,762 per patient. Assuming the improved life expectancy of AE patients is due to modern treatment the cost per disability-adjusted life years (DALY) saved is approximately Euro6,032. CONCLUSIONS: Current treatments have substantially improved the prognosis of AE patients compared to the 1970s. The cost per DALY saved is low compared to the average national annual income. Hence, AE treatment is highly cost-effective in Switzerland.

Relative survival is an adequate estimate of cancer-specific survival: baseline mortality-adjusted 10-year survival of 771 rectal cancer patients.

BACKGROUND The objective of the present investigation is to assess the baseline mortality-adjusted 10-year survival of rectal cancer patients. METHODS Ten-year survival was analyzed in 771 consecutive American Joint Committee on Cancer (AJCC) stage I-IV rectal cancer patients undergoing open resection between 1991 and 2008 using risk-adjusted Cox proportional hazard regression models adjusting for population-based baseline mortality. RESULTS The median follow-up of patients alive was 8.8 years. The 10-year relative, overall, and cancer-specific survival were 66.5% [95% confidence interval (CI) 61.3-72.1], 48.7% (95% CI 44.9-52.8), and 66.4% (95% CI 62.5-70.5), respectively. In the entire patient sample (stage I-IV) 47.3% and in patients with stage I-III 33.6 % of all deaths were related to rectal cancer during the 10-year period. For patients with AJCC stage I rectal cancer, the 10-year overall survival was 96% and did not significantly differ from an average population after matching for gender, age, and calendar year (p = 0.151). For the more advanced tumor stages, however, survival was significantly impaired (p < 0.001). CONCLUSIONS Retrospective investigations of survival after rectal cancer resection should adjust for baseline mortality because a large fraction of deaths is not cancer related. Stage I rectal cancer patients, compared to patients with more advanced disease stages, have a relative survival close to 100% and can thus be considered cured. Using this relative-survival approach, the real public health burden caused by rectal cancer can reliably be analyzed and reported.

Long term relative survival after surgery for abdominal aortic aneurysm in Western Australia: population based study

Objective: To determine the long term relative survival of all patients who had surgery for abdominal aortic aneurysm in Western Australia during 1985-94.

Five-year survival after first-ever stroke and related prognostic factors in the Perth Community Stroke Study

Background and Purpose-Few community-based studies have examined the long-term survival and prognostic factors for death within 5 years after an acute first-ever stroke. This study aimed to determine the absolute and relative survival and the independent baseline prognostic Factors for death over the next 5 years among all individuals and among 30-day survivors after a first-ever stroke in a population of Perth, Western Australia. Methods-Between February 1989 and August 1990, all individuals with a suspected acute stroke or transient ischemic attack of the brain who were resident in a geographically defined region of Perth, Western Australia, with a population of 138 708 people, were registered prospectively and assessed according to standardized diagnostic criteria. Patients were followed up prospectively at 4 months, 12 months, and 5 years after the index event. Results-Three hundred seventy patients with first-ever stroke were registered, and 362 (98%) were followed up at 5 years, by which time 210 (58%) had died. In the first year after stroke the risk of death was 36.5% (95% CI, 31.5% to 41.4%), which was 10-fold (95% CI, 8.3% to 11.7%) higher than that expected among the general population of the same age and sex. The most common cause of death was the index stroke (64%). Between 1 and 5 years after stroke, the annual risk of death was approximately 10% per year, which was approximately 2-fold greater than expected, and the most common cause of death was cardiovascular disease (41%). The independent baseline factors among 30-day survivors that predicted death over 5 years were intermittent clandication (hazard ratio [WR], 1.9; 95% CI, 1.2 to 2.9), urinary incontinence (HR, 2.0; 95% CI, 1.3 to 3.0), previous transient ischemic attack (HR, 2.4; 95% CT, 1.3 to 4.1), and prestroke Barthel Index <20/20 (HR, 2.0, 95% CI, 1.3 to 3.2). Conclusions-One-year survivors of first-ever stroke continue to die over the next 4 years at a rate of approximately 10% per year, which is twice the rate expected among the general population of the same age and sex. The most common cause of death is cardiovascular disease. Long-term survival after stroke may be improved by early, active, and sustained implementation of effective strategies for preventing subsequent cardiovascular events.

Long-term survival of women with breast cancer in New South Wales

Several long-term studies of breast cancer survival have shown continued excess mortality from breast cancer up to 20-40 years following treatment. The purpose of this report was to investigate temporal trends in long-term survival from breast cancer in all New South Wales (NSW) women. Breast cancer cases incident in 1972-1996 (54,228) were derived from the NSW Central Cancer Registry a population-based registry which began in 1972. All cases of breast cancer not known to be dead were matched against death records. The expected survival for NSW women was derived from published annual life tables. Relative survival analysis compared the survival of cancer cases with the age, sex and period matched mortality of the total population. Cases were considered alive at the end of 1996, except when known to be dead. Proportional hazards regression was employed to model survival on age, period and degree of spread at diagnosis. Survival at 5, 10, 15, 20 and 25 years of follow-up was 76 per cent, 65 per cent, 60 per cent, 57 per cent and 56 per cent. The annual hazard rate for excess mortality was 4.3 per cent in year 1, maximal at 6.5 per cent in year 3, declining to 4.7 per cent in year 5, 2.7 per cent in year 10, 1.4 per cent in year 15, 1.0 per cent for years 16-20, and 0.4 per cent for years 20-25 of follow-up. Relative survival was highest in 40-49 year-olds. Cases diagnosed most recently (1992-1996) had the highest survival, compared with cases diagnosed in previous periods. Five-year survival improved over time, especially from the late 1980s for women in the screening age group (50-69 years). Survival was highest for those with localised cancer at diagnosis: 88.4 per cent, 79.1 per cent, 74.6 per cent, 72.7 per cent and 72.8 per cent at 5, 10, 15, 20 and 25 years follow-up (excluding those aged greater than or equal to 70 years). There was no significant difference between the survival of the breast cancer cases and the general population at 20-25 years follow-up. Degree of spread was less predictive of survival 5-20 years after diagnosis, compared with 0-5 years after diagnosis, and was not significant at 20-25 years of follow-up. Relative survival from breast cancer in NSW women continues to decrease to 25 years after diagnosis, but there is little excess mortality after 15 years follow-up, especially for those with localised cancer at diagnosis, and the minimal excess mortality at 20-25 years of follow-up is not statistically significant. (C) 2002 Elsevier Science Ltd. All rights reserved.

Ten-year survival after first-ever stroke in the Perth Community Stroke Study

Background and Purpose-Very few studies have provided information regarding long-term prognosis after stroke. We aimed to determine the absolute and relative survival over 10 years among patients with first-ever stroke from a population-based study in Perth, Western Australia. Methods-For a 12-month period beginning February 1989, all individuals with a suspected acute stroke or transient ischemic attack who were resident in a geographically defined and representative region of Perth, Western Australia, were registered prospectively and assessed according to standardized diagnostic criteria. Patients with a definite first-ever stroke were followed up prospectively at 4 months, 12 months, 5 years, and 10 years after the index event. Results-A total of 251 patients with first-ever stroke were registered, and 244 (97%) were followed up at 10 years, by which time 197 (79%; 95% confidence interval [CI], 74 to 84) had died. The major causes of death were the direct effects of the initial stroke (27%; 95% CI, 21 to 33) and cardiovascular disease (26%; 95% CI, 20 to 32). Among 1-year survivors of stroke, the average annual case fatality was 4.8%, which was 2.3 (95% CI, 1.9 to 2.7) times greater than for the general population of the same age and sex. Conclusions-One in 5 patients with first-ever stroke survived to 10 years. The average annual case fatality was 4.8% between years 1 and 10 after stroke, which was twice that expected for the general population. Vascular disease is the major cause of death among long-term survivors of stroke.

Breast cancer five-year survival in New South Wales women, 1972 to 1991

This study of breast cancer survival is based on analysis of five-year relative survival of 38 362 cases of invasive breast cancer in New South Wales (NSW) women, incident between 1972 and 1991, with follow-up to 1992, using data from the population-based NSW Central Cancer Registry. Survival was ascertained by matching the registry file of breast cancers against NSW death certificates from 1972 to 1992, mainly by automated probabilistic linkage. Absolute survival of cases was compared with expected survival of age- and period-matched NSW women. Proportional hazard regression analysis was used for examination of the effects on excess mortality of age, period of diagnosis and degree of spread at diagnosis. Relative survival at five years increased from 70 per cent in 1972-1976 to 77 per cent in 1987-1991. Survival improved during the 1970s and in the late 1980s. Regression analysis suggested that part of the improved survival in the late 1980s was due to lesser degree of spread at diagnosis, whereas the improved survival during the 1970s may have been due to treatment. Survival was better for those aged 40-49 years (RR = 0.86) and worse for those aged greater than or equal to 70 years (RR = 1.22) compared with the referent group (60-69 years). Excess mortality was much less for those with invasive localised disease than those with regional spread (RR = 3.1) or metastatic cancer (RR = 15.5) at diagnosis. For the most recent period (1987-1991), relative five-year survival was 90, 70 and 18 per cent, respectively, for the three degree-of-spread categories.

Breast cancer five-year survival, by New South Wales regions, 1980 to 1991

Breast cancer five-year relative survival was calculated for 16 urban and rural regions in New South Wales (NSW) for cases incident in 1980-1991. Survival analysis employed cancer registry data linked with the death register, and age- and period-matched regional mortality of NSW women, Proportional hazard regression analysis was used to compare excess mortality in breast cancer cases in each region. The effect of region was significant (P < 0.05) in the analysis, after age and the follow-up variable (and their intel action) were adjusted for, although no region was significantly different from the referent group (chosen because of average relative five-year survival). When degree of spread and its interactions were entered into che model, the effect of region became nonsignificant. A significant linear trend (P < 0.05) in the adjusted relative risk for excess mortality in breast cancer cases was noted when regions were divided into quartiles based on socioeconomic status, with higher relative risk in low-socioeconomic-status groups; this effect also disappeared with adjustment for degree of spread at diagnosis. There was no general effect of rurality versus capital city or other metropolitan centres. This study demonstrates a small effect of region of residence and implied socioeconomic status on breast cancer survival in NSW women, but this becomes nonsignificant when the data are adjusted for degree of spread at diagnosis, This suggests that earlier diagnosis would he of benefit in reducing minor inequalities in breast cancer survival in NSW women.

Incidence and survival of chronic myelomonocytic leukemia in Girona (Spain): a populationbased study, 1993-2007

Chronic myelomonocytic leukemia is a very rare blood cancer observed mostly in the elderly. Here we report the incidence trends and survival of patients with chronic myelomonocytic leukemia over a 15-year period (1993-2007). Cases were provided by the population-based Girona Cancer Registry. The crude incidence rate was 0.72/100,000 inhabitants/year. No statistically significant increase in trends was detected over the 15 years. Median overall survival was 28 months although survival markedly decreased with advancing age. The 5-years observed and relative survival were 20% and 29%, respectively. This is the first population-based study that reports the incidence and survival of chronic myelomonocytic leukemia in Spain

Survival of European patients diagnosed with lymphoid neoplasms in 2000-2002: results of the HAEMACARE project

The European Cancer Registry-based project on hematologic malignancies (HAEMACARE), setup to improve the availability and standardization of data on hematologic malignancies in Europe, used the European Cancer Registry-based project on survival and care of cancer patients (EUROCARE-4) database to produce a new grouping of hematologic neoplasma(defined by the International Classification of Diseases for Oncology, Third Edition and the 2001/2008 World Health Organization classifications) for epidemiological and public healthpurposes. We analyzed survival for lymphoid neoplasms in Europe by disease group, comparing survival between different European regions by age and sex. Design and Methods Incident neoplasms recorded between 1995 to 2002 in 48 population-based cancer registries in 20 countries participating in EUROCARE-4 were analyzed. The period approach was used to estimate 5-year relative survival rates for patients diagnosed in 2000-2002, who did not have 5years of follow up. Results: The 5-year relative survival rate was 57% overall but varied markedly between the definedgroups. Variation in survival within the groups was relatively limited across European regions and less than in previous years. Survival differences between men and women were small. The relative survival for patients with all lymphoid neoplasms decreased substantially after the age of 50. The proportion of ‘not otherwise specified’ diagnoses increased with advancing age.Conclusions: This is the first study to analyze survival of patients with lymphoid neoplasms, divided into groups characterized by similar epidemiological and clinical characteristics, providing a benchmarkfor more detailed analyses. This Europe-wide study suggests that previously noted differences in survival between regions have tended to decrease. The survival of patients with all neoplasms decreased markedly with age, while the proportion of ‘not otherwise specified’ diagnoses increased with advancing age. Thus the quality of diagnostic work-up and care decreased with age, suggesting that older patients may not be receiving optimal treatment

Survival of European patients diagnosed with lymphoid neoplasms in 2000-2002: results of the HAEMACARE project

The European Cancer Registry-based project on hematologic malignancies (HAEMACARE), set up to improve the availability and standardization of data on hematologic malignancies in Europe, used the European Cancer Registry-based project on survival and care of cancer patients (EUROCARE-4) database to produce a new grouping of hematologic neoplasma(defined by the International Classification of Diseases for Oncology, Third Edition and the 2001/2008 World Health Organization classifications) for epidemiological and public health purposes. We analyzed survival for lymphoid neoplasms in Europe by disease group, comparing survival between different European regions by age and sex. Design and Methods Incident neoplasms recorded between 1995 to 2002 in 48 population-based cancer registries in 20 countries participating in EUROCARE-4 were analyzed. The period approach was used to estimate 5-year relative survival rates for patients diagnosed in 2000-2002, who did not have 5 years of follow up. Results: The 5-year relative survival rate was 57% overall but varied markedly between the defined groups. Variation in survival within the groups was relatively limited across European regions and less than in previous years. Survival differences between men and women were small. The relative survival for patients with all lymphoid neoplasms decreased substantially after the age of 50. The proportion of ‘not otherwise specified’ diagnoses increased with advancing age.Conclusions: This is the first study to analyze survival of patients with lymphoid neoplasms, divided into groups characterized by similar epidemiological and clinical characteristics, providing a benchmark for more detailed analyses. This Europe-wide study suggests that previously noted differences in survival between regions have tended to decrease. The survival of patients with all neoplasms decreased markedly with age, while the proportion of ‘not otherwise specified’ diagnoses increased with advancing age. Thus the quality of diagnostic work-up and care decreased with age, suggesting that older patients may not be receiving optimal treatment

Variability in UVB Tolerances of Melanized and Nonmelanized Cells of Cryptococcus neoformans and C-laurentii

Solar radiation is one of the major factors responsible for the control of fungus populations in the environment. Inactivation by UVA and UVB radiation is especially important for the control of fungi that disperse infective units through the air, including fungi such as Cryptococcus spp. that infect their vertebrate hosts by inhalation. Cryptococcus neoformans produces melanin in the presence of certain exogenous substrates such as l-3,4 dihydroxyphenylalanine and melanization may protect the fungus against biotic and abiotic environmental factors. In the present study, we investigated the effect of exposure to an UVB irradiance of 1000 mW m(-2) (biologically effective weighted irradiance) on the survival of melanized and nonmelanized cells of four strains of C. neoformans and four strains of C. laurentii. The relative survival (survival of cells exposed to radiation in relation to cells not exposed) of cells grown 2, 4, 6 or 8 days on medium with or without L-dopa was determined after exposure to UVB doses of 1.8 and 3.6 kJ m(-2). Both the irradiance spectrum and the intensities of those doses are environmentally realistic, and, in fact, occur routinely during summer months in temperate regions. Differences in tolerance to UVB radiation were observed between the C. neoformans and C. laurentii strains. The C. neoformans strains were more susceptible to UVB radiation than the C. laurentii strains. In C. neoformans, differences in tolerance to radiation were observed during development of both melanized and nonmelanized cells. For most treatments (strain, time of growth and UVB dose), there were virtually no differences in tolerances between melanized and nonmelanized cells, but when differences occurred they were smaller than those previously observed with UVC. In tests with two strains of C. laurentii, there was no difference in tolerance to UVB radiation between melanized and nonmelanized cells during 8 days of culture; and in tests with four strains for less culture time (4 days) there were no significant differences in tolerance between melanized and nonmelanized cells of any strain of this species.

Métodos estatísticos aplicados à modelação de dados oncológicos

RESUMO: A estrutura demográfica portuguesa é marcada por baixas taxas de natalidade e mortalidade, onde a população idosa representa uma fatia cada vez mais representativa, fruto de uma maior longevidade. A incidência do cancro, na sua generalidade, é maior precisamente nessa classe etária. A par de outras doenças igualmente lesivas (e.g. cardiovasculares, degenerativas) cuja incidência aumenta com a idade, o cancro merece relevo. Estudos epidemiológicos apresentam o cancro como líder mundial na mortalidade. Em países desenvolvidos, o seu peso representa 25% do número total de óbitos, percentagem essa que mais que duplica noutros países. A obesidade, a baixa ingestão de frutas e vegetais, o sedentarismo, o consumo de tabaco e a ingestão de álcool, configuram-se como cinco dos fatores de risco presentes em 30% das mortes diagnosticadas por cancro. A nível mundial e, em particular no Sul de Portugal, os cancros do estômago, recto e cólon apresentam elevadas taxas de incidência e de mortalidade. Do ponto de vista estritamente económico, o cancro é a doença que mais recursos consome enquanto que do ponto de vista físico e psicológico é uma doença que não limita o seu raio de ação ao doente. O cancro é, portanto, uma doença sempre atual e cada vez mais presente, pois reflete os hábitos e o ambiente de uma sociedade, não obstante as características intrínsecas a cada indivíduo. A adoção de metodologia estatística aplicada à modelação de dados oncológicos é, sobretudo, valiosa e pertinente quando a informação é oriunda de Registos de Cancro de Base Populacional (RCBP). A pertinência é justificada pelo fato destes registos permitirem aferir numa população específica, o risco desta sofrer e/ou vir a sofrer de uma dada neoplasia. O peso que as neoplasias do estômago, cólon e recto assumem foi um dos elementos que motivou o presente estudo que tem por objetivo analisar tendências, projeções, sobrevivências relativas e a distribuição espacial destas neoplasias. Foram considerados neste estudo todos os casos diagnosticados no período 1998-2006, pelo RCBP da região sul de Portugal (ROR-Sul). O estudo descritivo inicial das taxas de incidência e da tendência em cada uma das referidas neoplasias teve como base uma única variável temporal - o ano de diagnóstico - também designada por período. Todavia, uma metodologia que contemple apenas uma única variável temporal é limitativa. No cancro, para além do período, a idade à data do diagnóstico e a coorte de nascimento, são variáveis temporais que poderão prestar um contributo adicional na caracterização das taxas de incidência. A relevância assumida por estas variáveis temporais justificou a sua inclusão numaclasse de modelos designada por modelos Idade-Período-Coorte (Age-Period-Cohort models - APC), utilizada na modelação das taxas de incidência para as neoplasias em estudo. Os referidos modelos permitem ultrapassar o problema de relações não lineares e/ou de mudanças súbitas na tendência linear das taxas. Nos modelos APC foram consideradas a abordagem clássica e a abordagem com recurso a funções suavizadoras. A modelação das taxas foi estratificada por sexo. Foram ainda estudados os respectivos submodelos (apenas com uma ou duas variáveis temporais). Conhecido o comportamento das taxas de incidência, uma questão subsequente prende-se com a sua projeção em períodos futuros. Porém, o efeito de mudanças estruturais na população, ao qual Portugal não é alheio, altera substancialmente o número esperado de casos futuros com cancro. Estimativas da incidência de cancro a nível mundial obtidas a partir de projeções demográficas apontam para um aumento de 25% dos casos de cancro nas próximas duas décadas. Embora a projeção da incidência esteja associada a alguma incerteza, as projeções auxiliam no planeamento de políticas de saúde para a afetação de recursos e permitem a avaliação de cenários e de intervenções que tenham como objetivo a redução do impacto do cancro. O desconhecimento de projeções da taxa de incidência destas neoplasias na área abrangida pelo ROR-Sul, levou à utilização de modelos de projeção que diferem entre si quanto à sua estrutura, linearidade (ou não) dos seus coeficientes e comportamento das taxas na série histórica de dados (e.g. crescente, decrescente ou estável). Os referidos modelos pautaram-se por duas abordagens: (i)modelos lineares no que concerne ao tempo e (ii) extrapolação de efeitos temporais identificados pelos modelos APC para períodos futuros. Foi feita a projeção das taxas de incidência para os anos de 2007 a 2010 tendo em conta o género, idade e neoplasia. É ainda apresentada uma estimativa do impacto económico destas neoplasias no período de projeção. Uma questão pertinente e habitual no contexto clínico e a que o presente estudo pretende dar resposta, reside em saber qual a contribuição da neoplasia em si para a sobrevivência do doente. Nesse sentido, a mortalidade por causa específica é habitualmente utilizada para estimar a mortalidade atribuível apenas ao cancro em estudo. Porém, existem muitas situações em que a causa de morte é desconhecida e, mesmo que esta informação esteja disponível através dos certificados de óbito, não é fácil distinguir os casos em que a principal causa de morte é devida ao cancro. A sobrevivência relativa surge como uma medida objetiva que não necessita do conhecimento da causa específica da morte para o seu cálculo e dar-nos-á uma estimativa da probabilidade de sobrevivência caso o cancro em análise, num cenário hipotético, seja a única causa de morte. Desconhecida a principal causa de morte nos casos diagnosticados com cancro no registo ROR-Sul, foi determinada a sobrevivência relativa para cada uma das neoplasias em estudo, para um período de follow-up de 5 anos, tendo em conta o sexo, a idade e cada uma das regiões que constituem o registo. Foi adotada uma análise por período e as abordagens convencional e por modelos. No epílogo deste estudo, é analisada a influência da variabilidade espaço-temporal nas taxas de incidência. O longo período de latência das doenças oncológicas, a dificuldade em identificar mudanças súbitas no comportamento das taxas, populações com dimensão e riscos reduzidos, são alguns dos elementos que dificultam a análise da variação temporal das taxas. Nalguns casos, estas variações podem ser reflexo de flutuações aleatórias. O efeito da componente temporal aferida pelos modelos APC dá-nos um retrato incompleto da incidência do cancro. A etiologia desta doença, quando conhecida, está associada com alguma frequência a fatores de risco tais como condições socioeconómicas, hábitos alimentares e estilo de vida, atividade profissional, localização geográfica e componente genética. O “contributo”, dos fatores de risco é, por vezes, determinante e não deve ser ignorado. Surge, assim, a necessidade em complementar o estudo temporal das taxas com uma abordagem de cariz espacial. Assim, procurar-se-á aferir se as variações nas taxas de incidência observadas entre os concelhos inseridos na área do registo ROR-Sul poderiam ser explicadas quer pela variabilidade temporal e geográfica quer por fatores socioeconómicos ou, ainda, pelos desiguais estilos de vida. Foram utilizados os Modelos Bayesianos Hierárquicos Espaço-Temporais com o objetivo de identificar tendências espaço-temporais nas taxas de incidência bem como quantificar alguns fatores de risco ajustados à influência simultânea da região e do tempo. Os resultados obtidos pela implementação de todas estas metodologias considera-se ser uma mais valia para o conhecimento destas neoplasias em Portugal.------------ABSTRACT: mortality rates, with the elderly being an increasingly representative sector of the population, mainly due to greater longevity. The incidence of cancer, in general, is greater precisely in that age group. Alongside with other equally damaging diseases (e.g. cardiovascular,degenerative), whose incidence rates increases with age, cancer is of special note. In epidemiological studies, cancer is the global leader in mortality. In developed countries its weight represents 25% of the total number of deaths, with this percentage being doubled in other countries. Obesity, a reduce consumption of fruit and vegetables, physical inactivity, smoking and alcohol consumption, are the five risk factors present in 30% of deaths due to cancer. Globally, and in particular in the South of Portugal, the stomach, rectum and colon cancer have high incidence and mortality rates. From a strictly economic perspective, cancer is the disease that consumes more resources, while from a physical and psychological point of view, it is a disease that is not limited to the patient. Cancer is therefore na up to date disease and one of increased importance, since it reflects the habits and the environment of a society, regardless the intrinsic characteristics of each individual. The adoption of statistical methodology applied to cancer data modelling is especially valuable and relevant when the information comes from population-based cancer registries (PBCR). In such cases, these registries allow for the assessment of the risk and the suffering associated to a given neoplasm in a specific population. The weight that stomach, colon and rectum cancers assume in Portugal was one of the motivations of the present study, that focus on analyzing trends, projections, relative survival and spatial distribution of these neoplasms. The data considered in this study, are all cases diagnosed between 1998 and 2006, by the PBCR of Portugal, ROR-Sul.Only year of diagnosis, also called period, was the only time variable considered in the initial descriptive analysis of the incidence rates and trends for each of the three neoplasms considered. However, a methodology that only considers one single time variable will probably fall short on the conclusions that could be drawn from the data under study. In cancer, apart from the variable period, the age at diagnosis and the birth cohort are also temporal variables and may provide an additional contribution to the characterization of the incidence. The relevance assumed by these temporal variables justified its inclusion in a class of models called Age-Period-Cohort models (APC). This class of models was used for the analysis of the incidence rates of the three cancers under study. APC models allow to model nonlinearity and/or sudden changes in linear relationships of rate trends. Two approaches of APC models were considered: the classical and the one using smoothing functions. The models were stratified by gender and, when justified, further studies explored other sub-models where only one or two temporal variables were considered. After the analysis of the incidence rates, a subsequent goal is related to their projections in future periods. Although the effect of structural changes in the population, of which Portugal is not oblivious, may substantially change the expected number of future cancer cases, the results of these projections could help planning health policies with the proper allocation of resources, allowing for the evaluation of scenarios and interventions that aim to reduce the impact of cancer in a population. Worth noting that cancer incidence worldwide obtained from demographic projections point out to an increase of 25% of cancer cases in the next two decades. The lack of projections of incidence rates of the three cancers under study in the area covered by ROR-Sul, led us to use a variety of forecasting models that differ in the nature and structure. For example, linearity or nonlinearity in their coefficients and the trend of the incidence rates in historical data series (e.g. increasing, decreasing or stable).The models followed two approaches: (i) linear models regarding time and (ii) extrapolation of temporal effects identified by the APC models for future periods. The study provide incidence rates projections and the numbers of newly diagnosed cases for the year, 2007 to 2010, taking into account gender, age and the type of cancer. In addition, an estimate of the economic impact of these neoplasms is presented for the projection period considered. This research also try to address a relevant and common clinical question in these type of studies, regarding the contribution of the type of cancer to the patient survival. In such studies, the primary cause of death is commonly used to estimate the mortality specifically due to the cancer. However, there are many situations in which the cause of death is unknown, or, even if this information is available through the death certificates, it is not easy to distinguish the cases where the primary cause of death is the cancer. With this in mind, the relative survival is an alternative measure that does not need the knowledge of the specific cause of death to be calculated. This estimate will represent the survival probability in the hypothetical scenario of a certain cancer be the only cause of death. For the patients with unknown cause of death that were diagnosed with cancer in the ROR-Sul, the relative survival was calculated for each of the cancers under study, for a follow-up period of 5 years, considering gender, age and each one of the regions that are part the registry. A period analysis was undertaken, considering both the conventional and the model approaches. In final part of this study, we analyzed the influence of space-time variability in the incidence rates. The long latency period of oncologic diseases, the difficulty in identifying subtle changes in the rates behavior, populations of reduced size and low risk are some of the elements that can be a challenge in the analysis of temporal variations in rates, that, in some cases, can reflect simple random fluctuations. The effect of the temporal component measured by the APC models gives an incomplete picture of the cancer incidence. The etiology of this disease, when known, is frequently associated to risk factors such as socioeconomic conditions, eating habits and lifestyle, occupation, geographic location and genetic component. The "contribution"of such risk factors is sometimes decisive in the evolution of the disease and should not be ignored. Therefore, there was the need to consider an additional approach in this study, one of spatial nature, addressing the fact that changes in incidence rates observed in the ROR-Sul area, could be explained either by temporal and geographical variability or by unequal socio-economic or lifestyle factors. Thus, Bayesian hierarchical space-time models were used with the purpose of identifying space-time trends in incidence rates together with the the analysis of the effect of the risk factors considered in the study. The results obtained and the implementation of all these methodologies are considered to be an added value to the knowledge of these neoplasms in Portugal.