Objective　To study the clinical features, diagnosis and treatment of multiple primary cancer of digestive tract (MPCDT). Methods　The clinical data of 33 cases of MPCDT were analysed retrospectively. Results　The incidence of MPCDT was 2.7% in all patients with primary cancer of digestive tract. 24 cases was synchronous carcinoma (SC), of whom, 20 was misdignosis. All the cases of SC received comprehensive treatment, including radical resection, traditional medicine and radiotherapy respectively. 9 cases were metachronous carcinoma (MC), of them, only 1 case misdiagnosed. All the MC cases received radical resection, palliative resection and radiotherapy. The 5-year survival rate in cases of MPCDT, SC and MC were 45.4%, 37.5% and 55.5% respectively. Conclusions　The incidence of MPCDT is low, but misdiagnosis rate is hight. For MPCDT, comprehensive treatment, and radical resection and re-operation should be done. It is advisable not to diagnose MC as recurrence or metastasis.

Objective To study the surgical treatment of duodenal invasion by cancer of hepatic flexure of (colon). Methods Clinical data of 15 cases of duodenal invasion by cancer of hepatic flexure of colon were analyzed retrospectively.Results Invasion of the second or third portion of the duodenum by cancer of the hepatic flexure of colon occurred in 15 cases.The duodenum was adhered to the cancer in 6 cases,(seromuscular) invasion by the tumor in 5 cases,and duodenocolic fistula in 4 cases. All of the cases received surgical (treatment). 8 cases were mucoid adenocarcinomas, 4 were poorly differentiated adenocarcinomas, two were moderately differentiated adenocarcinomas, and one was signet-ring cell carcinoma. One patient died (after) operation, and the five-year survival rate was 46.7%(7/15). Conclusions Duodenum is the first organ easily to be invaded by cancer of hepatic flexare of colon. Radical and en bloc resection of the colonic cancer and involved organs is the best therapeutic method. The key to recovery is correct treatment of the (surgical) defect of the duodenum.