The current TNM staging system classifies cytology positive (cyt+) gastric cancer (GC) as T4b disease (cTcNpM1), which implies poor survival. Negative peritoneal cytology before treatment predicts better outcomes compared with positive cytology which identifies itself as a modifiable factor. Our study serves to examine the evidence that supports down-grading of cyt+ status in locally advanced GC in the absence of distant metastases, and the role of subsequent salvage surgery, in facilitating meaningful survival benefit.
Systematic review of the PubMed, Medline, Embase, the Cochrane Library and Google Scholar were undertaken, limiting articles to those published from 1999 to April 2020. The following criteria were used for study inclusion: patients with (1) gastric adenocarcinoma who received (2) neoadjuvant treatment and subsequently proceeded to (3) salvage gastric resection. (4) All patients required pre-treatment staging laparoscopy with cytology and post-chemotherapy laparoscopy with cytology. Of 1363 articles, 10 were considered eligible.
Conversion rates varied between 23.1% to 100% in the 10 studies. Patients who have been down-staged from cyt+ (CY1P0/1) to cyt- (CY0P0) GC have prolonged survival compared to patients who failed to down-stage with first line chemotherapy. The results showed consistently improved median survival time when patients were down-staged to cyt- status and proceeded to R0 resection, over patients who had R1 or R2 resections or did not have resections but were palliated instead.
Cyt+ GC patients are a subset of patients who have been shown to have prolonged MST if down-staged by neoadjuvant chemotherapy followed by R0 resection. Staging laparoscopy in addition to conventional imaging, may aid in discerning the GC patients who could benefit from this finding. As MST and 2-/3-YS is reduced in cyt+ patients who undergo resection, staging laparoscopy and cytology can help identify patients who would benefit from a trial of NAC and repeat staging laparoscopy.