Yusuke Muneoka

Comprehensive genomic sequencing detects important genetic differences between right-sided and left-sided colorectal cancer

Objectives Anti-epidermal growth factor receptor (EGFR) therapy has been found to be more effective against left-sided colorectal cancer (LCRC) than right-sided colorectal cancer (RCRC). We hypothesized that RCRC is more likely to harbor genetic alterations associated with resistance to anti-EGFR therapy and tested this using comprehensive genomic sequencing. Materials and methods A total of 201 patients with either primary RCRC or LCRC were analyzed. We investigated tumors for genetic alterations using a 415-gene panel, which included alterations associated with resistance to anti-EGFR therapy: TK receptors (ERBB2, MET, EGFR, FGFR1, and PDGFRA), RAS pathway (KRAS, NRAS, HRAS, BRAF, and MAPK2K1), and PI3K pathway (PTEN and PIK3CA). Patients whose tumors had no alterations in these 12 genes, theoretically considered to respond to anti-EGFR therapy, were defined as “all wild-type”, while remaining patients were defined as “mutant-type”. Results Fifty-six patients (28%) and 145 patients (72%) had RCRC and LCRC, respectively. Regarding genetic alterations associated with anti-EGFR therapy, only 6 of 56 patients (11%) with RCRC were “all wild-type” compared with 41 of 145 patients (28%) with LCRC (P = 0.009). Among the 49 patients who received anti-EGFR therapy, RCRC showed significantly worse progression-free survival (PFS) than LCRC (P = 0.022), and “mutant-type” RCRC showed significantly worse PFS compared with “all wild-type” LCRC (P = 0.004). Conclusions RCRC is more likely to harbor genetic alterations associated with resistance to anti-EGFR therapy compared with LCRC. Furthermore, our data shows primary tumor sidedness is a surrogate for the non-random distribution of genetic alterations in CRC.

Cost-effectiveness of Paclitaxel + Ramucirumab Combination Therapy for Advanced Gastric Cancer Progressing After First-line Chemotherapy in Japan

PURPOSE The combination of paclitaxel + ramucirumab is a standard second-line treatment in patients with advanced gastric cancer. This therapy has been associated with increased median overall survival and progression-free survival compared with those with paclitaxel monotherapy. We evaluated the cost-effectiveness of paclitaxel + ramucirumab combination therapy in patients with advanced gastric cancer, from the perspective of health care payers in Japan. METHODS We constructed a Markov model to compare, over a time horizon of 3 years, the costs and effectiveness of the combination of paclitaxel + ramucirumab and paclitaxel alone as second-line therapies for advanced gastric cancer in Japan. Health outcomes were measured in life-years (LYs) and quality-adjusted (QA) LYs gained. Costs were calculated using year-2016 Japanese yen (¥1 = US

Pathogenic Germline BRCA1/2 Mutations and Familial Predisposition to Gastric Cancer

17.79) according to the social insurance reimbursement schedule and drug tariff of the fee-for-service system in Japan. Model robustness was addressed through 1-way and probabilistic sensitivity analyses. The costs and QALYs were discounted at a rate of 2% per year. The willingness-to-pay threshold was set at the World Health Organizations criterion of ¥12 million, because no consensus exists regarding the threshold for acceptable cost per QALY ratios in Japans health policy. FINDINGS Paclitaxel + ramucirumab combination therapy was estimated to provide an additional 0.09 QALYs (0.10 LYs) at a cost of ¥3,870,077, resulting in an incremental cost-effectiveness ratio of ¥43,010,248/QALY. The incremental cost-effectiveness ratio for the combination therapy was >¥12 million/QALY in all of the 1-way and probabilistic sensitivity analyses. IMPLICATIONS Adding ramucirumab to a regimen of paclitaxel in the second-line treatment of advanced gastric cancer is expected to provide a minimal incremental benefit at a high incremental cost per QALY. Based on our findings, adjustments in the price of ramucirumab, as well as improves in other clinical parameters such as survival time and adverse event in advanced gastric cancer therapy, are needed.

Prognostic significance of peritoneal lavage cytology at three cavities in patients with gastric cancer.

Most gastric cancers (GCs) are considered sporadic, however familial aggregation occurs in 10% of cases1, 2. Approximately 5% of GCs are caused by an autosomal dominant inherited trait, with carriers having a strongly increased risk of GC and other cancers3. Clinical criteria for this entity were defined by the International Gastric Cancer Linkage Consortium (IGCLC)4. Among these, hereditary diffuse gastric cancer (HDGC) is a well-known type of familial GC (FGC). About 40% of families fulfilling the clinical criteria for HDGC have germline CDH1 mutations5. A subset of the remaining families of HDGC, and ones fulfilling the criteria of other familial GC, harbor pathogenic germline mutation in other genes which associated with hereditary cancer predisposition syndromes4. Hereditary breast and ovarian cancer (HBOC) is one of the best-described inherited cancer predisposition syndromes, caused by pathogenic germline BRCA1 or BRCA2 (BRCA1/2) mutations6–9. The increased risks of cancers other than breast and ovarian cancers were observed in the carriers10. The association between germline BRCA1/2 mutation and increased risk of GC were demonstrated in previous studies for HBOC families11–14. Regarding FGC, a recent large-scale study demonstrated that germline BRCA2 mutations were identified in patients who had a family history which fulfilled the criteria of HDGC, but lacking CDH1 mutations15. Therefore, it is possible that germline BRCA1/2 mutations may cause familial predisposition to GC. Recent advances of comprehensive genomic analysis enable us to identify the genomic alterations in GC16. BRCA1/2 mutations were shown in the subset of GC tumor tissues, however the association between germline BRCA1/2 mutations and familial predisposition to GC were not fully understood. Previously we performed genomic sequencing of 207 Japanese GCs using 435-gene panel, and identified BRCA1/2 mutations in tumor17. In this study, we conducted BRCA1/2 genetic testing in seven Japanese GC patients whose tumor had BRCA1/2 mutations. We identified pathogenic germline BRCA1/2 mutations in three patients, who have a familial component of GC.