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Is D2 lymphadenectomy essential for cytology-positive gastric cancer? A propensity score-matched analysis
Gastrectomy is generally performed for gastric cancer with positive peritoneal lavage cytology (CY1) but no other distant metastases. However, the appropriate extent of lymphadenectomy is uncertain. We retrospectively compared the overall survival after standard and limited lymphadenectomy.
We reviewed the medical records in four institutions from 2007 to 2018. Eighty-two consecutive patients with CY1 but no other distant metastases who underwent gastrectomy were analyzed. D2 or D2+ lymphadenectomy was performed for 48 patients and <D2 lymphadenectomy for 34 patients. Overall survival was compared using the Kaplan-Meier method and log-rank test. To reduce selection bias, we conducted a propensity score matching analysis. The patients’ propensity scores were estimated using a logistic regression model based on the following variables; age, performance status score, Onodera’s prognostic nutritional index (PNI), clinical nodal status, extent of gastrectomy, macroscopic tumor type, and postoperative chemotherapy.
The full cohort analyses showed that patients were younger, had better PNIes, had more advanced cN, and a higher number received postoperative chemotherapy in the ≥D2 group than in the <D2 group. The median overall survival times were 23.0 months after ≥D2 lymphadenectomy and 13.1 months after <D2 lymphadenectomy (p = 0.010). Twenty-five pairs of patients were generated via propensity score matching. The clinical characteristics of the two groups were well matched. The median overall survival time was 23.2 months after D2 lymphadenectomy and 13.7 months after <D2 lymphadenectomy (p = 0.029).
The prognoses of CY1 gastric cancer patients were better after standard lymphadenectomy than after limited lymphadenectomy.
