Impact of tumor regression grade on recurrence after preoperative chemoradiation and gastrectomy for gastric cancer
Alexander P. Stark, Jeannelyn S. Estrella, Yi‐Ju Chiang, Prajnan Das, Bruce D. Minsky, Mariela A. Blum Murphy, Jaffer A. Ajani, Paul Mansfield, Brian D. Badgwell, Naruhiko Ikoma
Abstract
BACKGROUND AND OBJECTIVES: It is unknown whether the degree of response to preoperative therapy correlates with locoregional recurrence (LR) or distant recurrence (DR) after resection of gastric cancer. METHODS: Patients who underwent resection of gastric adenocarcinoma following chemotherapy and chemoradiation (1995-2015) were reviewed. The tumor regression grade (TRG) was defined by the percentage of viable tumor cells in the specimen (TRG0 = 0%; TRG1 = 1%-2%; TRG2 = 3%-50%; TRG3 ≥ 50%). The relationships among TRG, recurrence-free survival (RFS), LR, and DR were examined. RESULTS: Two hundred forty-seven patients met the inclusion criteria (TRG0, 52 [21%]; TRG1, 49 [20%]; TRG2, 98 [40%]; TRG3, 48 [19%]). LR and DR occurred in 6.1% and 32.0% of patients, respectively. No patient with TRG0 experienced LR. R1 resection (6%-15%) and LR (6%-8%) rates were similar among TRG1-3 patients. R1 resection was associated with LR (hazard ratio [HR], 17.85; P < .001). ypN status (HR, 2.44; P = .004) and linitis plastica (HR, 2.90; P < .001) were associated with DR. TRG was not independently associated with RFS, LR, or DR. CONCLUSIONS: TRG0 imparted excellent local control. However, TRG1-3 patients had similar R1 resection rates and therefore similar LR. DR is associated with ypN status and linitis plastica, not TRG.