Rare histotypes of epithelial biliary tract tumors: A literature review

The Italian Rare Biliary tract Cancer initiative (IRaBiCa): A multicentric observational study of Gruppo Oncologico dell'Italia Meridionale (GOIM) in collaboration with Gruppo Italiano Colangiocarcinoma (GICO)

INTRODUCTION

About 90% of cholangiocarcinomas are adenocarcinomas with glandular or tubular structures lined by epithelial cells, with no bile production and with a variable degree of differentiation, arising in the background of desmoplastic stroma. The remaining 10% is represented by rarer histological variants of which there is little knowledge regarding the biological behavior, molecular characterization, and sensitivity to the various possible therapies, including molecular-based treatments. Such rare tumors are described only in case reports or small retrospective series because of their exclusion from clinical trials. This national initiative, here presented, aims to address the following knowledge gap: a) how much does histological diversity translate into clinical manifestation variety? b) are those chemotherapy regimens, recommended for conventional biliary tract cancers, potentially active in rare variants?Therefore, epidemiological, pathological, and clinical characterization of series of rare biliary histotypes/variants, for which therapeutic and follow-up data are available, will be collected.

METHODS

An Italian task force on rare tumors of the biliary tract (IRaBiCa) has been created, whose initiative is a multicenter retrospective study involving 34 Italian cancer centers.Clinical data from approximately 100 patients will be collected and analyzed. Continuous variables will be presented as median ± standard deviation, while categorical variables will be expressed in terms of frequency. Kaplan-Maier analyses will be used to compare disease free, progression free and overall survival, according to the different histotypes.

CONCLUSIONS

We expect to gather novel data on rare histotypes of biliary tract cancer that will be useful to support their molecular and immunological characterization.

Epidemiology of Adenosquamous Carcinomas

Background

Adenosquamous carcinomas (ASCs) are a very rare histology containing cancer cells with both glandular-like (adeno) and squamous cell histologies, comprising typically a fraction of a percent of all solid tumors. The bulk of the literature on ASCs is comprised of case reports and small series, with the general finding that ASCs tend to have worse outcomes than either of their parent histologies. However, there is a lack of pan site-comparative studies in the literature that compare ASC clinicodemographic and survival outcomes with those of conventional adenocarcinomas (ACs) and squamous cell carcinomas (SCCs).

Methods

In this study, we summarize these outcomes in eight primary sites, comprising 92.7% of all ASC cases diagnosed from 1975 to 2020 in the Surveillance, Epidemiology, and End Results (SEER) database.

Results

Lung ASCs comprise 51.5% of all ASC cases, accounting for 1.1% of all lung cancer cases, followed by uterine/cervical cancers at 29.7% of all ASC cases, translating into 1.8% of all cancers in this site. In descending order, the remaining 20% of ASCs arise in pancreatic, oral cavity, biliary, esophageal, colorectal, and gastric sites, comprising between 0.1% and 0.7% of all cancers in these sites. Apart from pancreatic and oral cavity cancers, ASC tumors tended to favor higher rates of regional or distant disease at presentation with poor tumor differentiation compared to either AC or SCC histologies. After multivariable analysis, adjusting for age, sex, detection stage, grade differentiation, surgery, chemotherapy, and radiotherapy, except for oral cavity cancers, ASCs tended to have worse overall survivals compared to ACs (hazard ratios: 1.1 - 1.6) and SCC (1.0 - 1.3), with colorectal ASCs having the worse overall survival compared to colorectal ACs, with a hazard ratio of 1.4 (95% confidence interval: 1.3 - 1.6).

Conclusions

Overall, these results suggest that ASC outcomes are site specific, and in general, tend to have worse outcomes than nonvariant ACs and SCCs even after correction for common clinical and epidemiological factors. These cancers have a poorly understood but unique tumor biology that warrants further characterization.

Case report: Robust response to sintilimab in advanced distal cholangiocarcinoma with PD-L1 expression and DNA damage repair

Cholangiocarcinoma (CCA) is a highly heterogeneous tumor that occurs in the bile duct epithelium; adenosquamous carcinoma is a rare pathological subtype of CCA. The clinical treatment of patients with metastatic distal CCA poses significant challenges. We report a 53-year-old female diagnosed with a stage III adenosquamous carcinomas of distal CCA. Metastasis occurred 4 months postoperatively and she was diagnosed with stage IV disease. The patient was treated with Gemcitabine + Oxaliplatin (GEMOX) and Capecitabine + Oxaliplatin (CAPEOX), followed by sintilimab monotherapy. After two cycles of treatment, the patient achieved partial response (PR) and the lesion continued to shrink. After 37 months of follow-up, the patient's liver metastasis had almost completely disappeared, and complete response (CR) was achieved. Moreover, she had more than 46 months of disease progression-free survival (PFS). Immunohistochemical testing showed high expression of PD-L1, and next-generation sequencing revealed the presence of mutations in DNA damage repair (DDR) pathway genes. To the best of our knowledge, this is the first reported case of the successful treatment of metastatic distal adenosquamous CCA with sintilimab alone. Remarkably, patients of CCA with high PD-L1 expression and DDR pathway gene mutations may benefit from sintilimab treatment.

A case of rapidly progressing sarcomatous intrahepatic cholangiocarcinoma with suddenly appearing lymph node metastasis

BACKGROUND

The sarcomatous variant of carcinoma is relatively rare in intrahepatic cholangiocarcinoma (ICC). Sarcomatous ICC (SICC) is associated with a poorer prognosis compared with ICC. SICC is rarely diagnosed before surgery due to non-descriptive findings; it progresses rapidly, resulting in miserable prognosis. Here, we report a case of rapidly progressing SICC that showed a clinically significant tumor growth rate.

CASE PRESENTATION

A 77-year-old woman who had undergone ileocecal resection for cecal cancer 5 years previously was found to have elevated levels of the tumor marker carbohydrate antigen 19-9. Although an abdominal computed tomography (CT) scan did not detect any liver mass lesions until 3 months before this serum examination, the subsequent CT scan revealed a hypodensity 20 mm mass lesion in the right anterior section. Contrast-enhanced CT and magnetic resonance imaging revealed peripheral enhancement in the arterial-to-equilibrium phase. Fluorodeoxyglucose positron emission tomography revealed uptake in the lesion. None of the imaging modalities showed lymph node swelling or distant metastases. She underwent hepatectomy under the diagnosis of ICC or an atypical metastasis from previous cecal cancer. Although preoperative images showed no suspicious lymph node metastasis 3 weeks prior, the hilar lymph node swelled 3 cm and contained adenocarcinoma. Consequently, the patient underwent right anterior sectionectomy and lymph node dissection of the hepatoduodenal ligament. Histopathological examination revealed that the liver tumor was a poorly differentiated adenocarcinoma with sarcomatous pattern. While the patient received adjuvant gemcitabine and S-1 therapy, lymph node metastasis appeared in the mediastinum 13 months after the surgery. She received gemcitabine + cisplatin + S-1 therapy but died 20 months after surgery.

CONCLUSION

SICC and lymph node metastasis clinically appeared within 3 months and 3 weeks, respectively. Suspected ICC that rapidly progresses should be considered SICC and treated with early resection. SICC is often missed in clinical diagnosis and has a poor prognosis, even after curative resection. While an alternative strategy involving preoperative biopsy and neoadjuvant therapy may be beneficial, it should be approached with discretion due to the potential risks of tumor progression and peritoneal dissemination.

An overview of extrahepatic cholangiocarcinoma: from here to where?

Extrahepatic cholangiocarcinoma (eCCA) contains perihilar cholangiocarcinoma and distal cholangiocarcinoma both of which can arise at any point of the biliary tree and originate from disparate anatomical sites. Generally, the incidence of eCCA is increasing globally. Though surgical resection is the principal treatment of choice for the early stages of eCCA, optimal survival remains restricted by the high risk of recurrence when most patients are present with unresectable disease or distant metastasis. Furthermore, both intra- and intertumoral heterogeneity make it laborious to determine molecularly targeted therapies. In this review, we mainly focused on current findings in the field of eCCA, mostly including epidemiology, genomic abnormalities, molecular pathogenesis, tumor microenvironment, and other details while a summary of the biological mechanisms driving eCCA may shed light on intricate tumorigenesis and feasible treatment strategies.