Controversial Issues Regarding Obligatory Adjuvant Chemotherapy for Stage IIIA Colon Cancer

To investigate the survival outcomes of patients with stage IIIA colon cancer. In addition, risk factors that affect the oncologic outcome of stage IIIA colon cancer patients and the role of adjuvant chemotherapy were evaluated.

Data from 326 colon cancer patients with stage IIIA who underwent surgery between January 2000 and December 2016 were retrospectively reviewed. Patients diagnosed with hereditary cancer and those who received preoperative neoadjuvant therapy were excluded.

The 5-year recurrence-free survival (RFS) rate in stage IIIA colon cancer patients who underwent curative resection was 93.9%. Of the patients with recurrence, the survival rate of those who underwent surgical resection was better than that of patients who received palliative chemotherapy or no treatment (12/13, 92.3% vs. 2/4, 50.0%), respectively; P = .052). Multivariate analysis showed that high serum carcinoembryonic antigen (s-CEA) was an independent and statistically significant prognostic factor for RFS, and ulcerative gross-type disease tended to be a poor prognostic factor. There was no difference in RFS in patients with elevated s-CEA or ulcerative gross-type disease according to receipt of adjuvant chemotherapy.

Patients with stage IIIA colon cancer had a relatively favorable survival outcome. Even in patients with relapsed disease, long-term survival could be a result if surgical resection is accomplished. High s-CEA concentration is a significant poor prognostic factor for recurrence, and ulcerative gross-type disease tends to be a poor prognostic factor. Postoperative adjuvant chemotherapy may not provide a survival benefit for stage IIIA colon cancer, even in the presence of risk factors. Because of the rarity of this patient group and the low rate of recurrence, large-scale multicenter studies are needed to find and confirm the risk group that would receive a benefit from adjuvant chemotherapy.