Frisch M, Olsen J H, Bautz A, Melbye M
Epidemiology Research Unit, Danish Epidemiology Science Center, Statens Seruminstitut, Copenhagen.
N Engl J Med. 1994 Aug 4;331(5):300-2. doi: 10.1056/NEJM199408043310504.
Benign anal lesions are often considered to cause a predisposition to anal cancer. To reexamine this association, we linked national data on hospital discharge and cancer in Denmark.
After making certain exclusions, we used the Danish Central Hospital Discharge Register to identify 68,549 patients hospitalized with benign anal lesions between 1977 and 1989. Through computerized linkage to the Danish Cancer Registry, all incident cases of epidermoid anal cancer and colorectal cancer among these patients were identified. Follow-up for the occurrence of cancer started the month after the date of the first hospital discharge and continued until the patient died (10.6 percent of the sample), emigrated (0.7 percent), or was lost to follow-up (0.04 percent) or until December 31, 1989 (88.6 percent), whichever came first.
The median follow-up period was 6.2 years. There were 23 epidermoid anal cancers and 416 colorectal cancers. The overall relative risk of anal cancer (observed vs. expected cases) was 4.4 (95 percent confidence interval, 2.8 to 6.6). The relative risk was 12.0 (95 percent confidence interval, 5.2 to 23.6) within the first year after hospitalization for benign lesions, 4.6 (95 percent confidence interval, 2.3 to 8.3) from one to four years after hospitalization, and 1.8 (95 percent confidence interval, 0.5 to 4.7) five or more years after hospitalization. The risk of colorectal cancer was significantly increased only during the first year after hospitalization (relative risk, 2.6; 95 percent confidence interval, 2.1 to 3.1).
There is a strong temporal association between the diagnosis of benign anal lesions and the diagnosis of anal cancer. Although we could not exclude the possibility of a moderate increase in the long-term risk of anal cancer, our data do not support the view that benign anal lesions cause anal cancer.
良性肛门病变常被认为会导致患肛门癌的易感性。为重新审视这种关联，我们将丹麦全国的医院出院数据和癌症数据进行了关联。
在进行某些排除后，我们使用丹麦中央医院出院登记册，确定了1977年至1989年间因良性肛门病变住院的68549名患者。通过与丹麦癌症登记册的计算机化关联，确定了这些患者中所有表皮样肛门癌和结直肠癌的发病病例。癌症发生情况的随访从首次出院日期后的次月开始，持续到患者死亡（样本的10.6%）、移民（0.7%）、失访（0.04%）或直到1989年12月31日（88.6%），以先到者为准。
中位随访期为6.2年。有23例表皮样肛门癌和416例结直肠癌。肛门癌的总体相对风险（观察病例与预期病例）为4.4（95%置信区间，2.8至6.6）。良性病变住院后第一年内相对风险为12.0（95%置信区间，5.2至23.6），住院后1至4年为4.6（95%置信区间，2.3至8.3），住院后5年或更长时间为1.8（95%置信区间，0.5至4.7）。结直肠癌风险仅在住院后第一年内显著增加（相对风险，2.6；95%置信区间，2.1至3.1）。
良性肛门病变的诊断与肛门癌的诊断之间存在强烈的时间关联。虽然我们不能排除肛门癌长期风险适度增加的可能性，但我们的数据不支持良性肛门病变会导致肛门癌的观点。
