OBJECTIVETo investigate the clinicopathologic characteristics and prognosis of multiple primary synchronous colorectal carcinoma (synchronous CRC) and single colorectal carcinoma (single CRC).

METHODSClinicopathological data of 39 patients with synchronous CRC and 528 patients with single CRC from May 1996 to June 2001 were reviewed retrospectively.

RESULTSThe patients with synchronous CRC accounted for 6.9% of all the patients with colorectal carcinoma treated in our hospital during the same period. Compared with concurrent lesions, Dukes stage of the index lesions of synchronous CRC was more developed and the lymph node metastasis and vessel invasion occurred more frequently. In addition, it also had poorer differentiation. There were significant differences of Dukes stages and lymph node metastasis between the index lesions and single CRC. The incidence of adenomatous polyp in synchronous CRC was higher than that in single CRC(59.0% vs 25.0%,P<0.01). The sensitivity of preoperative colonoscopy examination was 76.9%, which was significantly higher than that of barium examination and exploration during operation. The total 5-year survival rate of synchronous CRC was significantly lower than that of single CRC (5.1% vs 28.2%,P=0.042), and no significant difference of total 5-year survival rate was found between single CRC patients and synchronous CRC patients undergone radical operation. Synchronous CRC patients undergone radical operation had longer survival as compared to those undergone palliative operation(P<0.01). Multivariate analysis indicated that Dukes stages, lymph node metastasis, vessel invasion and the type of operation were independent prognostic factors of synchronous CRC.

CONCLUSIONSSynchronous CRC and single CRC are not always similar in clinicopathologic characteristics and prognosis. Early finding, early diagnosis and radical operation are the keys to improve the survival rate of synchronous CRC.