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

Round 1

Reviewer 1 Report

Dear Editor, thank you so much for inviting me to revise this manuscript about biliary tract cancer.

The overall limited survival benefit provided by systemic therapies in this setting, with most patients reporting a survival rate of less than a year from the moment of diagnosis, has led to notable efforts towards the identification of novel targets and agents that could modify the natural history of these aggressive hepatobiliary malignancies. In fact, the massive use of next-generation sequencing (NGS) has led to the identification of previously unknown molecular features of CCA, including the presence of specific genetic aberrations that have been suggested to be distinctive features of iCCA and eCCA. Among these druggable alterations, fibroblast growth factor receptor (FGFR)2 gene fusions and rearrangements, isocitrate dehydrogenase-1 (IDH-1) mutations, and BRAF mutations have been widely described in CCA patients, reporting important differences between iCCA and eCCA.

 

Based on these premises, the paper addresses a timely topic.

The manuscript is quite well written and organized.

The introduction explains in a clear and coherent manner the background of this study.

 

We suggest the following modifications:

·      Although the authors correctly included important papers in this setting, we believe the background of medical treatment for cholangiocarcinoma should be better discussed in the introduction section, and some recently published papers added,  (PMID: 32824407; PMID: 33611090), only for a matter of consistency. We believe it would be useful to introduce the topic of this interesting manuscript.

 

·      In addition, we believe some issues deserve further discussion. In everyday clinical practice, we know that the pathologic confirmation of diagnosis is necessary before any non-surgical treatment and can be challenging in BTC, particularly in patients affected by primary sclerosing cholangitis and biliary strictures. In fact, decisions to undertake biopsies should follow a multidisciplinary discussion, especially in potentially resectable tumors. Moreover, endoscopic imaging and tissue sampling are useful but, sadly, biopsy samples are often inadequate for molecular profiling, and in addition, tissue sampling has reported high specificity but low sensitivity in diagnosis of malignant biliary strictures. Finally, the highly desmoplastic nature of BTC limits the accuracy of cytological and pathological approaches.

On the basis of these premises, in this scenario, it is urgent to develop new strategies in order to anticipate the diagnosis identifying BTC at an early, resectable stage, and to obtain sufficient material with which to perform genomic analysis. Among these strategies, liquid biopsy has received growing attention over the years, given the promising applications in cancer patients. More specifically, several studies have shown the potential role of liquid biopsy, and the authors should discuss this point, also reporting recent studies in this setting (doi: 10.3390/cells9030721; doi: 10.21873/cgp.20203).

 

We believe that major revisions are needed. The main strengths of this paper are that it addresses an interesting and very timely question and provides clear answers, with some limitations. We suggest and the addition of some references for a matter of consistency. Moreover, the authors should better clarify some points and should add some details and studies, as suggested.

Author Response

Please see the attachement.

Author Response File: Author Response.docx

Reviewer 2 Report

In this study, Masashi Kanai summarizes the current clinical practice for genomic profiling of biliary tract cancer in Japan. Biliary tract cancer, or cholangiocarcinoma, or CCA, is a progressive and heterogeneous cancer; therefore, early diagnosis is challenging, and treatment options are limited. It is important for readers to provide information for latest technology. The topic is timely and tempting. There are a few comments for this manuscript. The author emphasizes Japan, such as three CGP tests in Japan or four markers are reimbursed in Japan; however, when the author summarizes some topics, such as pembrolizumab or ivosidenib, the author cites studies using not only Japanese patients. This is slightly misleading and confusing for the readers. It would be great if the author discusses and summarizes the situation in Japan. For example, Japanese CCA patients have unique features, such as higher IDH1 mutation frequencies than other countries? The author mentions that Japan reimburses only four markers, but why? These four markers are quite common in Japanese patients? Previous CGP tests found any important findings or unique features in Japanese patients? What is the benefit to do CGP tests for Japanese patients? Chemotherapy or radiotherapy is not very effective to Japanese patients and hence need to perform CGP to identify the target? It would be helpful to introduce the unique features or situation or limitations in Japan and to discuss the benefits and importance of CGP for Japanese patients.

Author Response

Please see the attachment.

Author Response File: Author Response.docx

Reviewer 3 Report

However, there are some point which may be improved.

-In section 5, the author cite MOSCATO-01 trial which found actionable mutations in 68% of patients. The percentage seems promisingly high, but the prevalence of particular mutations in this study is not listed in the paper - please, provide this.

-In Table 2, frequency of NCCN approved mutations is listed. Compared to aforementioned MOSCATO-01, the overall frequency of targetable mutations is notably lower - how does the author explain this?

In Table 2, the author provide percentage of HER2 overexpression in anatomical subtypes of biliary cancer (intrahepatic, extrahepatic/ gall bladder). If avialable, it is of great interest to see this distribution also in the other gene targets.

Of note, it is known fact that intrahepatic cholangiocarcinoma contains targetable genomic profiles (i.e. FGFR2 fusion, IDH1/2 mutation, BAP1 mutation etc.). The molecular, proteomic and genomic differences may be explained by different embryology. The different frequency and spectrum of targetable mutations/fusions in particular anatomic cholangiocarcinoma subtypes (intrahepatic / extrahepatic) should be mentioned and discussed more deeply. See and eventualy cite:

Lowery MA, Ptashkin R, Jordan E, et al. Comprehensive Molecular Profiling of Intrahepatic and Extrahepatic Cholangiocarcinomas: Potential Targets for Intervention. Clin Cancer Res. 2018; 24(17): 4154-61. 

Kendall T, Verheij J, Gaudio E, Evert M, Guido M, Goeppert B, Carpino G. Anatomical, histomorphological  and molecular classification of cholangiocarcinoma. Liver Int. 2019; 39 Suppl 1:7-18.

-In section 6, the author mention that there is probably a subset of patients with germline pathogenic gene profiles missed

daily clinical practice. The author should provide a hypothesis or rationale supporting this claim

(i.e. overall frequency of hereditary cancer syndroms and technical explanation why the mutations may be missed).

 

Minor point (not mandatory):

-Although not a main focus of the article, not only genomic profiling is a relevant tissue-based therapy-predictive method. Prediction of pembrolizumab effect may be performed by PD-L1-immunohistochemistry.

In pancreatobiliary cancer, rare undifferentiated carcinoma with osteoclast-like giant cells (UCOGC) overexpress PD-L1 and the patients may benefit from anti-PD-L1 therapy. Although well documented in pancreatic cancer

(i.e. Luchini C, et al. (2018) PD-1, PD-L1, and CD163 in pancreatic undifferentiated carcinoma with osteoclast-like giant cells: expression patterns and clinical implications. Hum Pathol 81:157–165, Hrudka J, et al (2020) Negative prognostic impact of PD-L1 expression in tumor cells of undifferentiated (anaplastic) carcinoma with osteoclast-like giant cells of the pancreas: study of 13 cases comparing ductal pancreatic carcinoma and review of the literature. Virchows Arch 477:687–696)

This was well documented in pancreas, but the tumor rarely occurs also in bile ducts (Chen CH, Li HN. Undifferentiated Carcinoma with Osteoclast-Like Giant Cells of the Common Bile Duct: A Case Report of a Rare Entity at an Unusual Location. Diagnostics (Basel). 2022 Jun 21;12(7):1517)

The author may eventually broaden the Pembrolizumab discussion in this novel way of research - although not related to genomic profiling, the topic (UCOGC and pembrolizumab) is interesting because of reported curative treatment of metastatic UCOGC case (Obayashi M, et al. Pancreatic undifferentiated carcinoma with osteoclast-like giant cells curatively resected after pembrolizumab therapy for lung metastases: a case report. BMC Gastroenterol. 2020 Jul 11;20(1):220).

Author Response

Please see the attachment.

Author Response File: Author Response.docx

Round 2

Reviewer 1 Report

The authors addressed all the queries we raised.

We recommend Acceptance.