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AIM:To reduce the incidence and mortality of rectal cancerand address the hypothesis that colorectal cancer often arisefrom precursor lesion(s),either adenomas or non-adenomatous polyps,by conducting a population-basedmass screening for colorectal cancer in Haining County,Zhejiang,PRC.METHODS:From 1977 to 1980,physicians screened thepopulation of Haining County using 15 cm rigid endoscopy.Of over 240 000 participants,4076 of them were diagnosedwith precursor lesions,either adenomas or non-adenomatous polyps,which were then removed surgically.All individuals with precursor lesione were followed up andreexamined by endoscopy every two to five yearn up to 1998.RESULTS:After the initial screening,953 metachronousadenomas and 417 non-adenomatous polyps were detected andremoved from the members of this cohort.Further,27 cases ofcolorectal cancer were detected and treated.Log-rank testsshowed that the survival time among those cancer patients whounderwent mass screening increased significantly compared tothat of other colorectal cancer patients(P<0.0001).Accordingto the population-based cancer registry in Haining County,age-adjusted incidence and mortality of rectal cancer decreasedby 41% and 29% from 1977-1981 to 1992-1996,respectively.Observed cumulative 20-year rectal cancer incidence was 31%lower than the expected in the screened group;the mortalitydue to rectal cancer was 18% lower then the expected in thescreened group.CONCLUSION:Mass screening for rectal cancer andprecursor lesions with protocoscopy in the generalpopulation and periodical following-up with routineendoscopy for high-risk patients may decrease both theincidence and mortality of rectal cancer.
AIM: To reduce the incidence and mortality of rectal cancerand address the hypothesis that colorectal cancer often arise from precursor lesion (s), either adenomas or non-adenomatous polyps, by conducting a population-based mass screening for colorectal cancer in Haining County, Zhejiang, PRC .METHODS: From 1977 to 1980, physicians screened thepopulation of Haining County using 15 cm rigid endoscopy. Over 240,000 participants, 4076 of them were diagnosedwith precursor lesions, either adenomas or non-adenomatous polyps, which were then removed surgically. with precursor lesion were followed up and rexamined by endoscopy every two to five year up until 1998.RESULTS: After the initial screening, 953 metachronous adenomas and 417 non-adenomatous polyps were detected and remove from the members of this cohort. Further, 27 cases of colorectal cancer were detected and treated .Log-rank testsshowed that the survival time among those cancer patients whounderwent mass screening increased significantl Age-adjusted incidence and mortality of rectal cancer decreased by 41% and 29% from 1977-1981 to 1992-1996, respectively .Observed cumulative 20-year rectal cancer incidence was 31% lower than the expected in the screened group; the mortality rate to rectal cancer was 18% lower then the expected in the screened group. CONCLUSION: Mass screening for rectal cancer and precursor lesions with protocoscopy in the generalpopulation and periodical following-up with routine endoscopy for high-risk patients may decrease both theincidence and mortality of rectal cancer.