A. Obana1, K. Okada1, K. Kitamura1, T. Matsumura1, T. Suwa1, K. Karikomi1, M. Koyama1,2 1Kashiwa Kosei General Hospital,General Surgery,Kashiwa, CHIBA, Japan 2Hirosaki University for Cancer of The Colon and Rectum,Hirosaki, AOMORI, Japan
Introduction:
It is reported that the prognosis and response to chemotherapy for unresectable recurrent colon cancer are different according to the primary tumor location. This appears to be related to pathological and genetic aspects, which may have ramifications for both cancer surveillance and the adjuvant chemotherapy plan. We analyzed and compared the risk factors for recurrence of colon cancer classified as stage ? between the right and left colon.
Methods:
We reviewed 214 patients with stage ? colon cancer (including rectosigmoid) in multiple facilities from 1994 to 1997, 1999 to 2003, and performed histopathological evaluation retrospectively. All patients were classified by the primary tumor location, and the risk factors for recurrence were analyzed from clinical pathological aspects, including tumor depth, histology, lymph node metastasis, vascular invasion(ly,v), budding, extramural cancer deposition(EX), perineural invasion(PN), the number of dissected lymph nodes, and use of postoperative chemotherapy, as well as postoperative outcomes (recurrence rate, recurrence free survival rate). Chi-square test was used for univariate analysis, and multiple logistic regression analysis for multivariate analysis.
Results:
The 5 year disease-free survival rate (5Y DFS) was 66.1% for the right side of colon, and 66.7% for the left side. Multivariate analysis of right colon cancer cases showed that three independent factors associated with an increase in recurrence rate were tumor depth (T3:20.7%,T4:46.4%, P=0.010), lymph node metastasis (N1:25.7%,N2-3:51.4%,P=0.043), and perineural invasion (PN0:25.8%,PN1:46.5%,P=0.037). On the other hand, for the left colon, four independent factors associated with an increase in recurrence rate were tumor depth (T3:21.2%,T4:53.8%, P=0.021), lymph node metastasis (N1:22.5%,N2-3:55.9%,P=0.032), extramural cancer invasion (EX-:17.5%,EX+:52.1%, P=0.003), and histology (well-differentiated type:29.5%?other types:70.0%, P=0.008).
Conclusion:
Among patients with stage ? colon cancer, those with T4 and/or N2-3 have high recurrence rates after surgery. In addition, when the primary tumor is located on right side, patients with PN1 should be followed up carefully to detect early recurrence. On the other hand, when the primary tumor is located on left side, patients with EX+, mucinous carcinoma, or low differentiated adenocarcinoma should also undergo close follow-up.