Background: Minimally invasive surgery (MIS) is increasingly used to treat gastric cancer in the USA. A potential benefit of MIS is increased likelihood of receiving adjuvant chemotherapy. Our objectives were (1) to assess trends and predictors of MIS for gastric cancer, (2) to evaluate the association between MIS and postoperative chemotherapy, and (3) to investigate the relationship between MIS and survival.
Methods: Patients with T3 or greater and/or N+ gastric adenocarcinoma were identified from the National Cancer Database from 2010 to 2015. Patients aged ≥ 85, with metastatic disease, treated with only preoperative chemotherapy, or with contraindications to chemotherapy were excluded. Hierarchical logistic regression and Cox proportional hazards were used to assess associations between MIS and postoperative chemotherapy and survival.
Results: Of 21,872 gastric resections, 6083 (27.8%) were MIS and 15,789 (72.2%) open. The majority were partial/subtotal (68.3%). Utilization of MIS increased from 18 to 37% from 2010 to 2015 (p < 0.01). Predictors of MIS were Asian race, any insurance coverage, and treatment at high-volume centers. Among 7540 patients with locally advanced disease, MIS was associated with receiving postoperative chemotherapy compared to open surgery (77.7% vs. 71.9%; OR 1.31, 95% CI 1.11-1.54). MIS was associated with improved survival before adjusting for postoperative chemotherapy (HR 0.83; 95% CI 0.72-0.97) but not after (HR 0.87, 95% CI 0.75-1.01).
Discussion: Utilization of MIS for locally advanced gastric cancer approximately doubled during the study period. Compared to open surgery patients, MIS patients were more likely to receive postoperative chemotherapy. The increased utilization of postoperative chemotherapy may explain the associated survival advantage observed with MIS.
Keywords: Chemotherapy; Gastric cancer; Minimally invasive surgery.