Background: The prognosis of unresectable gastric cancer is poor. Chemotherapy occasionally converts an initially unresectable gastric cancer to a resectable cancer.
Methods: The responses of noncurative factors to initial chemotherapy and the outcomes of additional (conversion) surgery were retrospectively evaluated in 151 patients with unresectable gastric cancer receiving combination chemotherapy with S-1 plus cisplatin or paclitaxel from February 2003 to December 2013.
Results: Forty (26 %) of 151 patients underwent conversion surgery. After chemotherapy, R0 resection was accomplished in 32 patients (80 %). The 5-year overall survival (OS) rate among the 40 patients who underwent conversion surgery was 43 % (median survival time, 53 months). The 5-year OS rate in the 111 patients treated with chemotherapy alone was 1 % (median survival time, 14 months). Patients who underwent conversion surgery had significantly longer OS times than patients who underwent chemotherapy alone (P < 0.01). The 5-year OS rate among patients who underwent R0 resection was 49 % (median survival time, 62 months). Patients who underwent R0 resection had significantly longer OS times than those who underwent R1 and R2 resection (P = 0.03). Among patients who underwent conversion surgery, multivariate Cox regression analysis showed that one noncurative factor (odds ratio 0.49; 95 % confidence interval 0.28-0.88; P = 0.02) and R0 resection (odds ratio 0.52; 95 % confidence interval 0.28-0.95; P = 0.03) were significant independent predictors for favorable OS.
Conclusions: Patients with unresectable gastric cancer initially exhibiting one noncurative factor may obtain a survival benefit from chemotherapy and subsequent curative surgery.