Clinical implications and chemo-sensitivity of adjuvant chemotherapy in patients with poorly cohesive cells-gastric cancer

Purpose: Poorly cohesive cells-gastric cancer (PCC-GC) represents distinct features within the GC spectrum. The present study investigated the clinicopathologic characteristics and chemo-sensitivity for a relatively large cohort of PCC-GC patients.

Materials and methods: A total of 268 patients diagnosed with stage II or III PCC-GC were included. GC cell lines were also analyzed for drug sensitivity to 5-fluorouracil (5-FU) and oxaliplatin in vitro.

Results: One hundred fifteen (42.9%) patients were stage II and 153 (57.1%) were stage III. Two hundred twenty-three (83.2%) patients received adjuvant therapy. Among these patients, 139 (62.3%) received CAPOX and 84 (37.7%) received S-1. With a median follow-up of 38.9 (1.6-137.8) months, the estimated 5-year disease-free survival (DFS) and overall survival (OS) rates were 52.3% and 61.0%, respectively. In the univariate analysis, survival was significantly better in the adjuvant chemotherapy group than in the surgery only group. In the subgroup analysis, there was no significant difference in DFS or OS between the types of adjuvant chemotherapy for either disease stage. In vitro cell line analysis, different responses to 5-FU and oxaliplatin were observed in SRC and non-SRC, where the treatment in KATOIII cell lines with oxaliplatin had less effect at a higher concentration compared to non-SRC cell lines.

Conclusion: The current study found that adjuvant chemotherapy was not significantly associated with survival benefit for patients with resected stage II and III PCC-GC. Plus, S-1 showed numerically longer DFS and OS compared to CAPOX in PCC-GC patients, although no significant in the multivariate analysis.