The incidence of postoperative venous thrombosis among patients with ulcerative colitis

Background: Patients with Ulcerative Colitis (UC) have inherent prothrombotic tendencies. It is unknown whether this necessitates the use of additional perioperative anti-thrombotic prophylaxis when such patients require major surgery. Methods: The postoperative courses of 79 patients with UC undergoing 180 major abdominal and pelvic operations were examined for clinical and radiological evidence of venous thrombosis. Eighteen patients with Familial Adenomatous Polyposis (FAP) having surgery (35 operations) of similar magnitude were also studied. Standard anti-thrombosis prophylaxis was utilised in all patients. Results: Nine patients with UC were clinically suspected of developing postoperative venous thrombosis, but only three (3.8%) had their diagnosis confirmed radiologically (all had a pulmonary embolus). Therefore, the overall postoperative thrombosis rate, on an intention to treat basis, was 1.7% (3/180). No patient with FAP developed significant venous thrombosis. Conclusion: Standard perioperative antithrombotic modalities are sufficient to maintain any potential increase in postoperative thrombotic risk at an acceptable level in patients with UC undergoing operative intervention.

THE ROLE OF THE MECHANICAL ENVIRONMENT ON CANCER CELL TRANSMIGRATION AND MRNA LOCALIZATION

Most cancer-related deaths are due to metastasis formation, the ability of cancer cells to break away from the primary tumor site, transmigrate through the endothelium, and form secondary tumors in distant areas. Many studies have identified links between the mechanical properties of the cellular microenvironment and the behavior of cancer cells. Cells may experience heterogeneous microenvironments of varying stiffness during tumor progression, transmigration, and invasion into the basement membrane. In addition to mechanical factors, the localization of RNAs to lamellipodial regions has been proposed to play an important part in metastasis. This dissertation provides a quantitative evaluation of the biophysical effects on cancer cell transmigration and RNA localization. In the first part of this dissertation, we sought to compare cancer cell and leukocyte transmigration and investigate the impact of matrix stiffness on transmigration process. We found that cancer cell transmigration includes an additional step, ‘incorporation’, into the endothelial cell (EC) monolayer. During this phase, cancer cells physically displace ECs and spread into the monolayer. Furthermore, the effects of subendothelial matrix stiffness and endothelial activation on cancer cell incorporation are cell-specific, a notable difference from the process by which leukocytes transmigrate. Collectively, our results provide mechanistic insights into tumor cell extravasation and demonstrate that incorporation into the endothelium is one of the earliest steps. In the next part of this work, we investigated how matrix stiffness impacts RNA localization and its relevance to cancer metastasis. In migrating cells, the tumor suppressor protein, adenomatous polyposis coli (APC) targets RNAs to cellular protrusions. We observed that increasing stiffness promotes the peripheral localization of these APC-dependent RNAs and that cellular contractility plays a role in regulating this pathway. We next investigated the mechanism underlying the effect of substrate stiffness and cellular contractility. We found that contractility drives localization of RNAs to protrusions through modulation of detyrosinated microtubules, a network of modified microtubules that associate with, and are required for localization of APC-dependent RNAs. These results raise the possibility that as the matrix environment becomes stiffer during tumor progression, it promotes the localization of RNAs and ultimately induces a metastatic phenotype.

Do hereditary syndrome-related gynecologic cancers have any specific features?

Hereditary syndromes are responsible for 10 % of gynaecologic cancers, among which hereditary breastovarian cancer and hereditary non-polyposis colon cancer syndromes, known as HBOC and Lynch syndromes respectively, present the highest relative risk. The latter predisposes to endometrial cancer and both contribute to ovarian cancer. Cowden syndrome-related endometrial cancer and the increased risk of ovarian, uterine and cervical cancers associated with Peutz-Jeghers syndrome, are also demonstrated, while Li-Fraumeni syndrome patients are prone to develop ovarian and endometrial cancers. Despite these syndromes’ susceptibility to gynaecologic cancers being consensual, it is still not clear whether these tumours have any epidemiologic, clinical, pathologic or imaging specific features that could allow any of the intervening physicians to raise suspicion of a hereditary syndrome in patients without known genetic risk. Moreover, controversy exists regarding both screening and surveillance schemes. Our literature review provides an updated perspective on the evidence-based specific features of tumours related to each of these syndromes as well as on the most accepted screening and surveillance guidelines. In addition, some illustrative cases are presented.

Revisión sistemática utilidad de asa y calcio con o sin vitamina d en la prevención de cáncer colorrectal y la recurrencia de pólipos adenomatosos en paciente con riesgo de padecer esta patología

Introducción: El cáncer colorrectal es una patología con alto impacto en la salud pública, debido a su prevalencia, incidencia, severidad, costo e impacto en la salud mental y física del individuo y la familia. Ensayos clínicos realizados en pacientes con antecedente de infarto al miocardio que consumían ácido acetil salicílico (asa), calcio con y sin vitamina D, mostraron asociación entre el consumo de estos medicamentos y disminución en la incidencia en cáncer colorrectal y pólipos adenomatosos. Objetivo: Evaluar la literatura sobre el uso de asa, calcio con y sin vitamina D con relación a su impacto en la prevención del cáncer colorrectal y pólipos adenomatosos. Métodos: Se realizó revisión sistemática buscando ensayos clínicos realizados en pacientes con factores de riesgo para cáncer colorrectal y pólipos adenomatosos que usaron asa, calcio con y sin vitamina D fueron incluidos. Resultados: se escogieron 105 para la revisión sistemática. Conclusiones: Es necesario desarrollar más estudios que lleven a evaluar el efecto protector de la aspirina, calcio y vitamina D. En los artículos revisados la aspirina a dosis de 81 a 325 mg día se correlaciona con reducción de riesgo de aparición de CRC aunque la dosis ideal, el tiempo de inicio y la duración de la ingesta continua no son claros. Hacen falta estudios que comparen poblaciones con ingesta de asa a diferentes dosis.