Characterization and clinical outcomes of rare biliary adenosquamous carcinoma

Background

Data are scarce regarding biliary adenosquamous carcinoma (BASC) due to its low incidence. BASC displays a worse prognosis than adenocarcinoma and its specific treatment is still an unmet medical need. We conducted a description analysis of BASC including clinicopathologic parameters and treatment outcomes.

Methods

All consecutive patients with histologically proven BASC diagnosed in six French hospitals between 2000 and 2022 were enrolled and described.

Results

A total of 16 BASC, accounting for 1.4 % of all biliary tract carcinoma, were included and the BASC incidence increased steadily over the past 22 years. The median age at diagnosis was 70.7 years (min-max 31.4–82.0 years) with most women (62.5 %). At diagnosis, half of BASC patients had a localized stage. The primary tumor locations were shared between gallbladder cancers (n = 7) and cholangiocarcinoma (n = 7), with mainly an extra-hepatic disease (71.4 %). Median overall survival was 9.5 months (95 % CI = 2.1–14.8 months). A total of 13 (81.6 %) patients had undergone surgery with a median relapse-free survival of 3.8 months (95 % CI = 0.0–10.5 months). Five (38.5 %) patients received an adjuvant chemotherapy. A total of seven (43.8 %) patients were treated with chemotherapy for the occurrence of metastases with a median progression-free survival of 2.8 months (95 % CI = 0.8–4.1 months). No objective response was observed and stable disease was achieved in two patients (28.6 %).

Conclusions

BASC is a rare disease with an increased incidence, highlighting the diagnostic challenges. BASC population was associated with a poor prognostic and limited therapeutic response. Further molecular investigations should be performed to investigate new therapeutic options.