Current Clinical Practice of Precision Medicine Using Comprehensive Genomic Profiling Tests in Biliary Tract Cancer in Japan

Patient survey on cancer genomic medicine in Japan under the national health insurance system

In Japan, comprehensive genomic profiling (CGP) tests have been reimbursed under the national health care system for solid cancer patients who have finished standard treatment. More than 50,000 patients have taken the test since June 2019. We performed a nation-wide questionnaire survey between March 2021 and July 2022. Questionnaires were sent to 80 designated Cancer Genomic Medicine Hospitals. Of the 933 responses received, 370 (39.7%) were web based and 563 (60.3%) were paper based. Most patients (784, 84%) first learned about CGP tests from healthcare professionals, and 775 (83.1%) gave informed consent to their treating physician. At the time of informed consent, they were most worried about test results not leading to novel treatment (536, 57.4%). On a scale of 0-10, 702 respondents (75.2%) felt that the explanations of the test result were easy to understand (7 or higher). Ninety-one patients (9.8%) started their recommended treatment. Many patients could not receive recommended treatment because no approved drugs or clinical trials were available (102/177, 57.6%). Ninety-eight patients (10.5%) did not wish their findings to be disclosed. Overall satisfaction with the CGP test process was high, with 602 respondents (64.5%) giving a score of 7-10. The major reason for choosing 0-6 was that the CGP test result did not lead to new treatment (217/277, 78.3%). In conclusion, satisfaction with the CGP test process was high. Patients and family members need better access to information. More patients need to be treated with genomically matched therapy.

Current status and issues in genomic analysis using EUS-FNA/FNB specimens in hepatobiliary-pancreatic cancers

Comprehensive genomic profiling based on next-generation sequencing has recently been used to provide precision medicine for various advanced cancers. Endoscopic ultrasound (EUS)-guided fine-needle aspiration (EUS-FNA) and EUS-guided fine-needle biopsy (EUS-FNB) play essential roles in the diagnosis of abdominal masses, mainly pancreatic cancers. In recent years, CGP analysis using EUS-FNA/FNB specimens for hepatobiliary-pancreatic cancers has increased; however, the success rate of CGP analysis is not clinically satisfactory, and many issues need to be resolved to improve the success rate of CGP analysis. In this article, we review the transition from EUS-FNA to FNB, compare each test, and discuss the current status and issues in genomic analysis of hepatobiliary-pancreatic cancers using EUS-FNA/FNB specimens.

Discordant microsatellite instability findings in two samples from a patient with biliary cancer that responded to pembrolizumab

Microsatellite instability (MSI) is a key marker to predict response to immune checkpoint inhibitors; however, only 1-2% of biliary cancers have this genomic feature. In a patient with hilar biliary cancer, MSI was examined in two cancer specimens (forceps biopsy from the biliary stricture and endoscopic ultrasound-guided fine-needle aspiration biopsy [EUS-FNAB] from the adjacent lymph node). We observed discordant results, as high frequency of MSI was found only in the forceps biopsy. Although the FNAB sample was 10 times larger than that of the forceps biopsy, the tumor concentration was much lower, which is a possible reason for the discordance. Besides, immunohistochemistry of four mismatch-repair (MMR) proteins showed proficient MMR expressions. The tumor became refractory to gemcitabine, cisplatin, and S-1 but responded well to pembrolizumab. Caution is needed for sample selection and for interpretation of the test's results, to avoid missing rare chance for effective molecular target agents.

Current progress in perioperative chemotherapy for biliary tract cancer

Biliary tract cancer (BTCs) is a heterogeneous malignancy divided into cholangiocarcinoma, gallbladder cancer, and ampullary cancer. Due to little or no symptoms, most patients with BTCs are diagnosed with unresectable or metastatic disease. Only 20%-30% of all BTCs are suitable for potentially resectable diseases. Although radical resection with a negative surgical margin is the only potentially curative method for BTCs, most patients develop postoperative recurrence, which is associated with poor prognosis. Therefore, perioperative treatment is necessary to improve survival. There are very few randomized phase III clinical trials of perioperative chemotherapy due to the relative rarity of BTCs. Adjuvant chemotherapy with S-1 for patients with resected BTC significantly increased overall survival compared with upfront surgery in a recent ASCOT trial. In East Asia, S-1 is currently considered the standard adjuvant chemotherapy, while capecitabine may still be used in other areas. Since then, our phase III trial (KHBO1401), gemcitabine and cisplatin plus S-1 (GCS) has become the standard chemotherapy for advanced BTCs. GCS not only improved overall survival but demonstrated a high response rate. The efficacy of GCS as a preoperative neoadjuvant chemotherapy for resectable BTCs has been investigated in a randomized phase III trial (JCOG1920) in Japan. In this review, we summarize the current and ongoing clinical trials focusing on adjuvant and neoadjuvant chemotherapy for BTCs.