Natural history of colorectal cancer in hereditary nonpolyposis colorectal cancer (Lynch syndromes I and II)

Abstract

Approximately 5 to 6 percent of the total colorectal cancer burden is accounted for by hereditary nonpolyposis colorectal cancer (HNPCC). Because clinical premonitory signs such as those seen in familial polyposis coli (FPC) are lacking, the clinician must recognize clinical findings and family history typical of HNPCC. The authors have described colorectal cancer expression from a survey of ten HNPCC kindreds. Kindred members with colorectal cancer differed significantly (P less than .05) from patients with sporadic colorectal cancer: 1) mean age of initial colon cancer diagnosis was 44.6 years; 2) 72.3 percent of first colon cancers were located in the right colon, and only 25 percent were in the sigmoid colon and rectum; 3) 18.1 percent had synchronous colon cancers; and 4) 24.2 percent developed metachronous colon cancer, with a risk for metachronous lesions in ten years of 40 percent. Affecteds and their first-degree relatives should undergo early intensive education and surveillance. In families with an early age of onset, colonoscopy should begin at age 25, and biannually thereafter, with fecal occult blood testing of the stool semiannually. Third-party carriers must become more responsive to the costly surveillance measures required for these otherwise healthy patients.

Are there two sides to colorectal cancer?

“…In contrast, approximately 70% of large bowel tumours in HNPCC individuals arise in the right colon. 76 In addition to the highly penetrant but rare APC or DNA mismatch repair gene mutations responsible for FAP and HNPCC, respectively, common low-penetrance genetic variants that predispose to right or left colon cancers also exist. At least 50 studies have examined associations between various polymorphisms and CRC risk, 77 but relatively few have analysed according to subsite.…”

Microsatellite instability: new aspects in the carcinogenesis of colorectal carcinoma

“…HNPCC families presenting exclusively CRC have been designated as Lynch syndrome type I. Approximately 30% of HNPCC patients also develop carcinomas of other organs such as endometrium, stomach, biliopancreatic or urinary tract, which is referred to as Lynch syndrome type II [27].…”

A expressão de genes reparadores do DNA nos tumores sincrônicos de câncer colorretal esporádico

“…Estes pacientes freqüentemente apresentavam tumores de localização proximal, com componente mucinoso, estadiamento pTNM avançado, maior risco de lesões sincrônicas e metacrônicas 13 . Apesar de algumas características reconhecidamente associadas a pior prognóstico, Cólon direito -Ceco ao transverso distal Cólon esquerdo -Descendente ao sigmóide Reto -Reto FIGURA 1 -Tumor corado com anticorpo para MSH1 mostrando a positividade de immunoexpressão no tecido tumoral e no tecido normal adjacente FIGURA 2 -Tumor corado com anticorpo para MSH6 mostrando a ausência de immunoexpressão no tumor e a positividade no tecido normal adjacente curiosamente estes pacientes parecem estar associados a melhores resultados de sobrevivência tardia e menor risco de recidiva 19 .…”