Is There Any Role of Adjuvant Chemotherapy for T3N0M0 or T1N2M0 Gastric Cancer Patients in Stage II in the 7th TNM but Stage I in the 6th TNM System?

Controversy surrounds adjuvant chemotherapy (CTx) for T3N0M0 and T1N2M0 in the American Joint Committee on Cancer (AJCC) 7th edition stage IIA gastric cancer patients. The purpose of this study was to evaluate the benefit of adjuvant CTx for stage IIA cancer, including T3N0M0 and T1N2M0. A total of 630 patients with stage IIA cancer who underwent a radical gastrectomy between January 1999 and December 2009 at Seoul National University Hospital were retrospectively analyzed. We compared the outcomes of 434 patients who did not receive CTx (the non-CTx group) with those of 196 patients who received CTx comprising of 5-fluorouracil-based regimens (the CTx group). The 5-year overall survival (OS) rates of the non-CTx and CTx groups were 86.4 and 89.3 %, respectively (p = 0.047). In the subgroup analysis of T2N1M0 (6th II/7th IIA), there was a significant difference in OS between the non-CTx and CTx groups (p = 0.003), but no differences were observed in T3N0M0 and T1N2M0 (6th IB/7th IIA) (p = 0.574 and p = 0.934). The multivariate analysis showed that a tumor size greater than 5 cm in T3N0M0 [odds ratio (OR) 1.929; p = 0.030], no adjuvant CTx in T2N1M0 (OR 4.853; p = 0.025), and no factors in T1N2M0 were found to be risk factors for recurrence-free survival. Adjuvant CTx may be associated with an improved outcome of patients with T2N1M0 (6th II/7th IIA), but not T3N0M0 or T1N2M0 (6th IB/7th IIA), gastric cancer. To confirm these results, further studies are needed.