5-fluorouracil, mitomycin-C, and polysaccharide-K adjuvant chemoimmunotherapy for locally advanced gastric cancer: the prognostic significance of frequent perineural invasion

Abstract

BACKGROUND/AIMS: Although adjuvant chemotherapy has demonstrated small but significant survival benefit in locally advanced gastric cancer in several meta-analyses, optimal chemotherapy regimen remains to be determined. METHODOLOGY: We retrospectively analyzed the survival of 207 gastric cancer patients (stage IB: 19, II: 65, IIIA: 58, IIIB: 28, IV: 37) who underwent 5-fluorouracil (5-FU), mitomycin-C (MMC), and polysaccharide-K (PSK) chemoimmunotherapy (CITX) after curative resection (FM group). The survival of FM group was compared with that of historical control cohort of 103 patients with almost identical stage distribution who received 5-FU and doxorubicin-based chemotherapy (FA group). RESULTS: Five-year disease-free survival and overall survival (OS) of FM group were 58.7% and 59.1%, respectively. Frequent perineural invasion was significantly associated with poor OS (p = 0.01) in multivariate analysis. There was no statistically significant difference in 5-year OS (59.1% vs. 56.2%, p = 0.637) between FM and FA groups. FM group showed superior 5-year OS (84.4% vs. 67.6%, p = 0.019) compared with FA group in stage IB or II patients without significant difference (p = 0.222) in stage IIIA to IV. CONCLUSIONS: 5-FU, MMC, and PSK CITX is as effective as 5-FU and doxorubicin-based chemotherapy. Moreover, frequent perineural invasion seems to be an important poor prognostic factor.