Reliability of a measure of prediagnosis physical activity for cancer survivors

Purpose: This study was conducted to examine the test-retest reliability of a measure of prediagnosis physical activity participation administered to colorecial cancer survivors recruited from a population-based state cancer registry. Methods: A total of 112 participants completed two telephone interviews. I month apart, reporting usual weekly physical activity in the year before their cancer diagnosis. Intraclass correlation coefficients (ICC) and standard en-or of measurement (SEM) were used to describe the test-retest reliability of the measure across the sample: the Bland-Altman approach was used to describe reliability at the individual level. The test-retest reliability for categorized total physical activity (active, insufficiently active, sedentary) was assessed using the kappa statistic. Results: When the complete sample was considered, the ICC ranged from 0.40 (95% Cl: 0.24, 0.55) for vigorous gardening to 0.77 (95% Cl: 0.68, 0.84) for moderate physical activity. The SEM, however, were large. indicating high measurement error. The Bland-Altman plots indicated that the reproducibility of data decreases as the aniount of physical activity reported each week increases The kappa coefficient for the categorized data was 0.62 (95% Cl: 0.48, 0.76). Conclusion: Overall. the results indicated low levels of repeatability for this measure of historical physical activity. Categorizing participants as active, insufficiently active, or sedentary provides a higher level of test-retest reliability.

Searching for cancer deaths in Australia: National Death Index vs Cancer Registries

OBJECTIVE: To compare the accuracy, costs and utility of using the National Death Index (NDI) and state-based cancer registries in determining the mortality status of a cohort of women diagnosed with ovarian cancer in the early 1990s. METHODS: As part of a large prognostic study, identifying information on 822 women diagnosed with ovarian cancer between 1990 and 1993, was simultaneously submitted to the NDI and three state-based cancer registries to identify deceased women as of June 30, 1999. This was compared to the gold standard of "definite deaths". A comparative evaluation was also made of the time and costs associated with the two methods. RESULTS: Of the 450 definite deaths in our cohort the NDI correctly identified 417 and all of the 372 women known to be alive (sensitivity 93%, specificity 100%). Inconsistencies in identifiers recorded in our cohort files, particularly names, were responsible for the majority of known deaths not matching with the NDI, and if eliminated would increase the sensitivity to 98%. The cancer registries correctly identified 431 of the 450 definite deaths (sensitivity 96%). The costs associated with the NDI search were the same as the cancer registry searches, but the cancer registries took two months longer to conduct the searches. CONCLUSIONS AND IMPLICATIONS: This study indicates that the cancer registries are valuable, cost effective agencies for follow-up of mortality outcome in cancer cohorts, particularly where cohort members were residents of those states. For following large national cohorts the NDI provides additional information and flexibility when searching for deaths in Australia. This study also shows that women can be followed up for mortality with a high degree of accuracy using either service. Because each service makes a valuable contribution to the identification of deceased cancer subjects, both should be considered for optimal mortality follow-up in studies of cancer patients.

Trends for in situ and invasive melanoma in Queensland, Australia, 1982-2002

Objectives Queensland, the north-eastern state of Australia, has the highest incidence of melanoma in the world. Control measures started earlier here than probably anywhere else in the world; early detection programmes started in the 1960s and primary prevention in the 1980s. Data from the population-based Queensland Cancer Registry therefore provide an internationally unique data source with which to assess trends for in situ and invasive melanomas and to consider the implications for early detection and primary prevention. Methods We used Poisson regression to estimate the annual percentage change in rates across 21 years of incidence data for in situ and invasive lesions, stratified by age and sex. Joinpoint analyses were used to assess whether there had been a statistically significant change in the trends. Results In situ melanomas increased by 10.4% (95% CI: 10.1%, 11.1%) per year among males and 8.4% (7.9%, 8.9%) per year among females. The incidence of invasive lesions also increased, but not as quickly; males 2.6% (2.4%, 2.8%), females 1.2% (0.9%, 1.5%). Valid data on thickness was only available for 1991 to 2002 and for this period thin-invasive lesions were increasing faster than thick-invasive lesions (for example, among males: thin 3.8%, thick 2.0%). We found some suggestive evidence of lower proportionate increase for the most recent years for both in-situ and invasive lesions, but this did not achieve statistical significance. Among people younger than 35 years, the incidence of invasive melanoma was stable and there was a suggestion of a birth cohort effect from about 1958. Mortality rates were stable across all ages, and there was a suggestion of decreasing rates among young women, although this did not achieve statistical significance. Conclusion Age-standardised incidence is continuing to increase and this, in combination with a shift to proportionately more in situ lesions, suggests that the stabilisation of mortality rates is due, in large part, to earlier detection. For primary prevention, after a substantial period of sustained effort in Queensland, there is some suggestive, but not definitive, evidence that progress is being made. Incidence rates are stabilising in those younger than 35 years and the proportionate increase for both in situ and invasive lesions appears to be lower for the most recent period compared with previous periods. However, even taking the most favourable view of these trends, primary prevention is unlikely to lead to decreases in the overall incidence rate of melanoma for at least another 20 years. Consequently, the challenge for primary prevention programmes will be to maintain momentum over the long term. If this can be achieved, the eventual public-health benefits are likely to be substantial.