Adjuvant Chemotherapy with or without Concurrent Radiotherapy for Patients with Stage IB Gastric Cancer: a Subgroup Analysis of the Adjuvant Chemoradiotherapy in Stomach Tumors (ARTIST) Phase III Trial

Purpose: We aimed to discuss the roles of radiation and chemotherapy as adjuvant treatment in patients with staged IB GC who were enrolled in the adjuvant chemoradiotherapy in stomach tumors (ARTIST) trial. Materials and Methods: Among the 458 patients who were enrolled in the ARTIST trial, 99 had stage IB disease. The patients were randomly assigned to receive either adjuvant chemoradiotherapy with capecitabine plus cisplatin (XP, n=50) or chemoradiotherapy (XPRT, n=49). Survival analyses were performed in accordance with the AJCC 2010 staging system. Results: According to the AJCC 2010 system, stage migration from IB to II occurred in 71% of the patients; 98% of the T2 N0 cases were reclassified as T3 N0, and 42% of the T1 N1 cases were reclassified as T1 N2. When comparing survival outcomes between the XPRT and XP arms for stage IB cancer (AJCC 2002), no significant difference in 5-year disease-free survival (DFS) between the 2 arms was found. (median 5-year DFS, not reached, P=0.256). The patients classified as having stage IB cancer (AJCC 2002) and reclassified as having stage II cancer (AJCC 2010) exhibited worse prognoses than those who remained in stage IB, although the difference was not statistically significant (5-year DFS rate, 83% vs. 93%). When we compared 5-year DFS in 70 patients with stage II (AJCC 2010), the addition of radiotherapy to XP chemotherapy did not show better outcome than XP alone (P=0.137). Conclusions: The role of adjuvant chemoradiotherapy in the treatment of stage IB GC (AJCC 2002) warrants further investigation.