Reduction of the incidence and mortality of rectal cancer by polypectomy: a prospective cohort study in Haining County.
OBJECTIVE
To reduce the incidence and mortality of rectal cancer and 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 the population of Haining County using 15 cm rigid endoscopy. Of over 240000 participants, 4076 of them were diagnosed with precursor lesions, either adenomas or non-adenomatous polyps, which were then removed surgically. All individuals with precursor lesions were followed up and reexamined by endoscopy every two to five years up to 1998.


RESULTS
After the initial screening, 953 metachronous adenomas and 417 non-adenomatous polyps were detected and removed from the members of this cohort. Further, 27 cases of colorectal cancer were detected and treated. Log-rank tests showed that the survival time among those cancer patients who under went mass screening increased significantly compared to that of other colorectal cancer patients (P<0.0001). According to the population-based cancer registry in Haining County, 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 due to rectal cancer was 18% lower than the expected in the screened group.


CONCLUSIONS
Mass screening for rectal cancer and precursor lesions with protocoscopy in the general population and periodical following-up with routine endoscopy for high-risk patients may decrease both the incidence and mortality of rectal cancer.
Zheng
Shu
S
Cancer Institute, Zhejiang University, 88 Jiefang Road, HangZhou 310009, Zhejiang Province, China. zhengshu@mail.hz.zj.cn
Liu
Xi-Yong
XY
Ding
Ke-Feng
KF
Wang
Lin-Bo
LB
Qiu
Pei-Lin
PL
Ding
Xin-Feng
XF
Shen
Yong-Zhou
YZ
Shen
Gao-Fei
GF
Sun
Qi-Rong
QR
Li
Wei-Dong
WD
Dong
Qi
Q
Zhang
Su-Zhan
SZ
D000236:Adenoma / Q000601:surgery; D000328:Adult; D000368:Aged; D002681:China / Q000453:epidemiology; D015331:Cohort Studies; D005260:Female; D006801:Humans; D007417:Intestinal Polyps / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012004:Rectal Neoplasms / Q000453:epidemiology / Q000401:mortality / Q000517:prevention & control* / Q000601:surgery