Factors predicting worse prognosis in patients affected by pT3 N0 colon cancer : long-term results of a monocentric series of 137 radically resected patients in a 5-year period

BACKGROUND AND PURPOSE: For patients with stage II colon cancer, the use of adjuvant chemotherapy remains controversial. The purpose of this study was to identify clinical and/or pathological findings related to a worse prognosis in this category of patients. PATIENTS AND METHODS: We retrospectively analyzed the data of consecutive patients, extracted by an institutional tumor registry, admitted to an affiliated university hospital in Milan (European Institute of Oncology) for adenocarcinoma of the colon (all sites), between 2000 and 2005, and having a final pT3 N0 pathology staging after curative surgery. Adjuvant chemotherapy was decided as a result of a medical decision within a multidisciplinary tumor board. RESULTS: Data of 137 patients were obtained, with a median follow-up of 77 months (range 6-131). Patients who received chemotherapy were younger than patients who did not. Nine patients out of 137 (6.5 %) died as a consequence of colon cancer recurrence; four of them had received adjuvant chemotherapy. Only histological grade III and mucinous histotype were found to impact on cumulative incidence of colon-related events (p = 0.03 and 0.02, respectively); no impact was found on cumulative incidence of colonic neoplasm recurrence-related deaths (p = 0.74 and 0.74, respectively). Number of analyzed lymph nodes (LNs) emerged as a factor possibly affecting the cumulative incidence of colon-related events (p = 0.09) as well as the cumulative incidence of colonic neoplasm recurrence-related deaths (p = 0.10). The risk of events was inversely proportional to the number of dissected LNs, even over 20 up to about 25 LNs. Never smokers exhibited a lower incidence of colon-related events, although the difference was not statistically significant (p = 0.09). All other analyzed variables did not show any impact on survival rate, including age, gender, ASA score, body mass index, site of colonic neoplasm, multifocality, perivascular invasion, and use of adjuvant chemotherapy. CONCLUSIONS: Histology grading G3 and mucinous histotype were predictors of worse outcome. Efforts to improve LN evaluation should result in clinically significant improvements in outcome and also the quality of care for patients with radically resected stage II colon cancer.