Flexible sigmoidoscopy or colonoscopy as a screening modality for colorectal adenomas in older age groups? Findings in a cohort of the normal population aged 63-72 years

Abstract

Background-Most cases of colorectal cancer originate from adenomas. Removing adenomas has been shown to reduce the incidence of colorectal cancer. The design of cost eVective endoscopic screening programmes requires a knowledge of the distribution of adenomas in diVerent age groups. Aim-To investigate the distribution of colorectal adenomas in older age groups in the normal population. Method-A total of 356 men and women selected randomly from the population register were oVered a colonoscopic screening examination to detect and remove polyps. Results-In all, 241(68%) subjects, mean age 67.4 years (range 62-73), attended. The caecum was intubated in 193 (80%), and in this group 32 (38%) women and 51 (47%) men had adenomas. One hundred and ten (54%) of the adenomas and 11 (39%) of the "high risk adenomas" (adenomas larger than 10 mm in diameter, adenomas containing villous components, and adenomas with severe dysplasia) were found proximal to the sigmoid colon. In 36 (43%) of the subjects with adenomas, the adenomas were only found proximal to the sigmoid colon. Twenty two (11%) subjects had more than two adenomas. Of 203 adenomas discovered, 189 (93%) were less than 10 mm in diameter. Conclusion-More than half of the adenomas were localised proximal to the sigmoid colon, and, in nearly half of the adenoma bearing subjects examined, the adenoma was proximal to the descending colon. This indicates that a sigmoidoscopic screening examination in this age group would miss a substantial number of adenomas, but this may be acceptable as the vast majority of proximal adenomas do not progress to clinical cancer within the life expectancy of this age group. (Gut 1999;45:834-839)

Diagnostic value of distal colonic polyps for prediction of advanced proximal neoplasia in an average-risk population undergoing screening colonoscopy

“…54 Imperiale et al 19 found a significant association between hyperplastic distal polyps and APN. Our results, however, confirm those of other studies 18,32,[55][56][57][58][59] that show that hyperplastic polyps are not predictors of APN. Results differ when the predictive value of different characteristics of distal adenomas were studied in multivariate anal yses.…”

“…Most studies of the association between distal and proximal neoplasia are compromised by selection bias, including specific subgroups. [22][23][24][25][26][27][28][29][30][31][32][33][34][35] Only studies wherein colonoscopy is offered as a primary screening procedure can appropriately address this issue. Currently, such data that are available derive from 3 studies that comprise relatively few cases [36][37][38] and two large studies carried out in the United States.…”

Colonoscopia ou sigmoidoscopia: risco de lesões isoladas no cólon direito

“…Atualmente está bem estabelecida a importância da transformação adenoma para adenocarcinoma na gênese do câncer colorretal e que a polipectomia é método eficaz na sua profilaxia (9,12,13,14,15,16) . As recomendações aceitas para rastreamento do CCR incluem pesquisa de sangue oculto anual e sigmoidoscopia a cada três ou cinco anos, ambos a partir dos 50 anos, para pacientes de risco médio, e mais precocemente para vigilância de pacientes de alto risco .…”

“…Apesar da descrição do câncer "de novo", está bem definida a seqüência adenoma-carcinoma na história natural do CCR (13,14) , sendo a polipectomia reconhecida como profilaxia eficaz (7,12,16) . Diagnóstico precoce é a forma mais eficaz para diminuir a mortalidade do CCR (8) .…”

Serrated lesions of the colon

“…Кроме того, отмечается цитоплаз матическая эозинофилия, наличие бокаловидных клеток, отсутствие утолщения базальной мембраны под поверхностным эпителием, относительное ис чезновение эндокринных клеток, формирование ту булярного и ворсинчатого компонента. Пролифера ция эпителия в зубчатых аденомах происходит на уровне нижних отделов крипт, в чем проявляется уникальный характер генетического повреждения в этом типе колоректального полипа [31][32][33][34].…”