Multicenter experience with large panel next-generation sequencing in patients with advanced solid cancers in Japan

Background Application of next-generation DNA sequencing (NGS) has recently become increasingly common in the field of clinical oncology in several countries around the world. In Japan also, a system for applying NGS to routine clinical practice is gradually being established. During this process, we introduced in Japan the tumor-profiling MSK-IMPACT (Memorial Sloan Kettering-Integrated Mutation Profiling of Actionable Cancer Targets) assay. Methods We present here our initial experience with the use of MSK-IMPACT in 68 patients selected from two institutions in Japan between June 2016 and October 2017. Results MSK-IMPACT sequencing was successful and yielded results in specimens obtained from 64 of the 68 patients, representing an overall assay success rate of 94.1%. The top three cancer types tested were endometrial cancer (17.2%), pancreatic cancer (15.6%) and colorectal cancer (12.5%). Evaluation of the clinical actionability of the genetic alterations revealed that 25.0% of patients (n = 16) harbored at least one actionable alteration. However, enrolling the patients in a genomically matched clinical trial was difficult, mainly because most clinical trials are limited to tumors arising from a specific organ/site. One patient with microsatellite instability-high status, as determined by MSK-IMPACT, was treated with pembrolizumab and showed partial response. Conclusions Although tumor profiling by NGS and administration of genomically matched therapy is a promising strategy, because of its high cost, we need to consider how we can fit it into the Japanese medical system. Towards this end, we believe that it is important to share our initial experience for furthering precision medicine in Japan.