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Background: The tumor mutational burden (TMB) is a genomic biomarker associated with the benefits from immune checkpoint inhibitors (ICIs) cancer therapy. An elevated blood TMB (bTMB) in circulating tumor DNA (ctDNA) represents a compelling non-invasive diagnostic approach; however, the validity and utility of this emerging biomarker across cancer types have not been examined. Patient and methods: The blood and tissue TMB was measured in a large pan-tumor clinical cohort and the MONSTAR-SCREEN observational study (UMIN000036749) using the FoundationOne Liquid CDx and FoundationOne CDx assays. A subset of the MONSTAR-SCREEN cohort was used to evaluate the association between the bTMB and the efficacy of ICIs therapy. Results: The majority of cancer types showed similar prevalence of TMB≥10 mutations/megabase and bTMB≥10. There was high concordance between bTMB and TMB in blood and tissue biopsy from the same patient when the plasma tumor fraction (TF) was at least 1% (Spearman's coefficient 0.74 and > 80% sensitivity to detect TMB-high). High microsatellite instability (MSI-H) was detected by ctDNA with 79% sensitivity when TF was at least 1%, but only 6% sensitivity when TF was

Colorectal cancer (CRC) is one of the most common malignant diseases. Generally, stoma construction is performed following surgery for the resection of the primary tumor in patients with CRC. The association of CRC with the gut microbiota has been widely reported, and the gut microbiota is known to play an important role in the carcinogenesis, progression, and treatment of CRC. In this study, we compared the microbiota of patients with CRC between with and without a stoma using fecal metagenomic sequencing data from SCRUM-Japan MONSTAR-SCREEN, a joint industry-academia cancer research project in Japan. We found that the composition of anaerobes was reduced in patients with a stoma. In particular, the abundance of Alistipes, Akkermansia, Intestinimonas, and methane-producing archaea decreased. We also compared gene function (e.g., KEGG Orthology and KEGG pathway) and found that gene function for methane and short-chain fatty acids (SCFAs) production was underrepresented in patients with a stoma. Furthermore, a stoma decreased Shannon diversity based on taxonomic composition but increased that of the KEGG pathway. These results suggest that the feces of patients with a stoma have a reduced abundance of favorable microbes for cancer immunotherapy. In conclusion, we showed that a stoma alters the taxonomic and functional profiles in feces and may be a confounding factor in fecal microbiota analysis.

Abstract Background A previous phase I/II C-TASK FORCE study of trifluridine/tipiracil plus bevacizumab for patients with heavily pretreated metastatic colorectal cancer (mCRC) showed promising activity with an acceptable toxicity profile. This retrospective study aimed to investigate the safety and efficacy of trifluridine/tipiracil plus bevacizumab compared with trifluridine/tipiracil monotherapy in patients with heavily pretreated mCRC in clinical settings. Methods Records of patients with mCRC refractory to standard therapies who initiated trifluridine/tipiracil plus bevacizumab from January 2016 to March 2018 or trifluridine/tipiracil monotherapy from June 2014 to December 2015 were retrospectively reviewed at our institution. Results Totally, 60 patients received trifluridine/tipiracil plus bevacizumab and 66 received trifluridine/tipiracil monotherapy. All patients had previously received standard chemotherapy. Median progression-free survival (PFS) was 3.7 months [95% confidence interval (CI), 2.3–5.1] in the trifluridine/tipiracil plus bevacizumab group and 2.2 months (95% CI, 1.8–2.6) in the trifluridine/tipiracil monotherapy group [hazards ratio (HR) 0.69; 95% CI 0.48–0.99]. PFS rate at 16 weeks was 46.6% for the trifluridine/tipiracil plus bevacizumab group and 33.9% for the trifluridine/tipiracil monotherapy group. Although a relatively higher incidence of grade ≥ 3 neutropenia was observed in the trifluridine/tipiracil plus bevacizumab group than that in the other group (50.0% vs. 40.9%, p = 0.371), the incidence of febrile neutropenia was not high (3.3% vs. 7.8%, p = 0.444). Conclusions In real-world settings, trifluridine/tipiracil plus bevacizumab prolonged PFS and helped achieve higher 16-week PFS rate compared with trifluridine/tipiracil monotherapy in patients with heavily pretreated mCRC with manageable toxicities. Trial registration Retrospectively registered.