Treatment Pattern for Advanced Gastric Cancer in Japan and Factors Associated with Sequential Treatment: A Retrospective Administrative Claims Database Study

INTRODUCTION: Clinical trials have proven the efficacy and safety of new therapies for advanced gastric cancer (AGC), but how those therapies are used in the real world is poorly described. Real-world treatment patterns of antitumor therapies and factors associated with overall therapy duration in patients with AGC in Japan were investigated. METHODS: This retrospective cohort study used a Japanese administrative claims database (June 2014 to September 2019). Patients with AGC who started the guideline-recommended first-line combination regimens with platinum and fluoropyrimidine agents between June 2015 and July 2019 were included. Cox regression analysis was performed to identify factors associated with overall therapy duration (first line to last administration of guideline-listed agent). RESULTS: Of the 10,581 patients included, the most common first-line combination regimen without trastuzumab was S-1 plus oxaliplatin (4327/9069 patients; 47.7%) and with trastuzumab was capecitabine plus cisplatin (608/1512 patients; 40.2%). Most common second- and third-line regimens were ramucirumab plus taxane (3650/5358 patients; 68.1%) and nivolumab (1229/2390 patients; 51.4%), respectively. Factors positively associated with longer overall therapy duration were: oral fluoropyrimidine in first line (hazard ratio [95% confidence interval]: 0.63 [0.57–0.69]); trastuzumab in any line (0.73 [0.68–0.78]); treatment at a designated cancer hospital (0.89 [0.84–0.94]); dietary consultation within 1 month before/after start of first line (0.92 [0.86–0.98]); and treatment at a surgical department (0.94 [0.89–0.99]). Negatively associated factors were: edema (1.21 [1.07–1.37]); physical therapy (1.21 [1.12–1.31]); nutritional intervention (1.21 [1.14–1.28]) within 1 month before/after start of first line; thrombosis (1.13 [1.04–1.23]); renal disease (1.11 [1.02–1.21]); age (1.07 [1.02–1.13]); and peritoneal metastasis/ascites (1.06 [1.01–1.13]). CONCLUSIONS: In real-world treatment practice for AGC in Japan, therapy choice after the recommended first-line chemotherapy was consistent with guidelines. Factors associated with overall therapy duration were identified, which may assist in optimizing treatment sequence. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s12325-021-01931-3.