Precision oncology for advanced-stage adenocarcinoma of the appendix: comprehensive molecular characterisation identifies actionable lesions and potential predictive biomarkers.

Appendiceal adenocarcinoma is a rare cancer with very limited therapeutic options. We aimed to determine whether molecular profiling of advanced appendiceal adenocancer can identify actionable therapeutic alterations. We retrospectively analysed cohorts from two large German precision oncology programmes. Patient records and pathology reports from 19 patients with advanced appendiceal adenocarcinoma who were enrolled between 2015 and 2021 were included in this study. We report the molecular features, the resulting molecular tumour board recommendations and their clinical implementation. In 95% of the tumours, at least one potentially actionable alteration was identified, including mutations in ATM, PIK3CA and AKT1. An elevated tumour mutational burden was identified in 26% of the tumours. A total of 74% of all patients received a molecularly driven treatment recommendation, of which 2 (11%) received the recommended therapy. Molecular profiling of appendiceal adenocarcinomas revealed potentially actionable alterations in a number of cases.