OBJECTIVETo study the clinical characteristics, diagnosis, strategy of treatment and prognosis of multiple primary cancers in the digestive system.

METHODSAll malignant lesions in the digestive system encountered in the past 10 years were analysed by a computer software.

RESULTS116 cases of multiple cancers were observed with an incidence of 1.74%. Male to female ratio was 2.7:1. There were 62 synchronous carcinomas and 54 metachronous ones. In decreasing sequence, they were: colon > stomach > rectum > liver. The 1-, 3-and 5-year survival rates of the synchronous ones were 42.3%, 23.1% and 11.5%. Those of metachronous ones were 95.2%, 85.7% and 76.2%.

CONCLUSIONHigh frequency of multiple primary cancers is found in the colon, especially over the right side. Metachronous carcinomas usually give better prognosis than the synchronous ones. The longer the interval between the development of the two primary lesions, the better the prognosis. Multiple cancers of the colon have satisfactory prognosis. The key to improve the treatment is to be vigilant against lesions in the digestive tract so as to arrive at a timely diagnosis and treatment. The strategy of combining radical treatment with immuno-supportive therapy is advocated.