Trends in right and left-sided colon cancer

Abstract

The increasing ratio of proximal to distal colorectal carcinomas was confirmed in this population-based study of 668 new cases diagnosed among Rochester, Minnesota residents between 1940 and 1979. The change was due to a rise in the incidence of proximal lesions (from 15.1 per 100,000 person-years in 1940-59 to 17.3 per 100,000 in 1960-79) and a simultaneous fall in the incidence of distal lesions (from 35.5 to 28.2 per 100,000 person-years). Changes in definitions or referral patterns played no role in these observations, although improved diagnostic capabilities may have had an impact on the incidence of proximal lesions. These discrepant changes in incidence strongly suggest that proximal and distal colonic cancers are different diseases or have a different pathogenesis. The changing incidence rates were not associated with consistent differences in clinical characteristics at the time of initial diagnosis.

Havep53gene mutations and protein expression a different biological significance in colorectal cancer?*

“…Some other authors have con®rmed our results revealing that overexpression of p53 and certain p53 mutations, in the conserved areas or in speci®c exons of the gene (Jernvall et al, 1997;Diez et al, 2000), were signi®cantly higher in distal than in proximal CRC. These data would seem to support the observations made by Weisburger (1991), that proximal and distal tumors involve different types of epidemiological behavior, and by (Beart et al, 1983) regarding the existence of two different pathways of tumoral progression of CRCs originating in the two tracts.…”

Clinico-pathological and oncological differences between right and left-sided colon cancer (stages I-III): analysis of 950 cases

“…These differences were first reported by Beart and Buffill (4,5) in the 1980s and 1990s and were corroborated by O'Dwyer (6) in stage IV disease in 2001. This phenomenon has aroused great interest, as tumor location influences survival in both stage III and IV disease (7).…”

Colorectal carcinoma among ethnic Chinese in Singapore

“…The widespread use of colonoscopy and sigmoidoscopy has been credited with reducing the risk of colorectal carcinoma, particularly for patients in Western countries with distal lesions. 31,32 The decline in colorectal carcinoma risk observed among white individuals in the U. S. since the mid-1980s is especially striking with regard to distal lesions, and is consistent with the higher reported use of endoscopic examination after the publicity surrounding former President Ronald Reagan's diagnosis of colon carcinoma in 1985. 31 Thus, advances in early detection technologies may account for at least some of the temporal changes in subsite specific incidence rates observed in the U. S. However, in Singapore colonoscopy or sigmoidoscopy is not the norm, and routine endoscopic polypectomies in the large bowel only began in the late 1980s, which is much later than in the U. S. In addition, there are no guidelines concerning early detection, screening, and surveillance for colorectal carcinoma available locally for high risk patients.…”