Comprehensive genomic landscape and precision therapeutic approach in biliary tract cancers

Biliary tract cancers have dismal prognoses even when cytotoxic chemotherapy is administered. There is an unmet need to develop precision treatment approaches using comprehensive genomic profiling. A total of 121 patients with biliary tract cancers were analyzed for circulating‐tumor DNA (ctDNA) and/or tissue‐based tumor DNA (tissue‐DNA) using clinical‐grade next‐generation sequencing: 71 patients (59%) had ctDNA; 90 (74%), tissue‐DNA; and 40 (33%), both. Efficacy of targeted therapeutic approaches was assessed based upon ctDNA and tissue‐DNA. At least one characterized alteration was detected in 76% of patients (54/71) for ctDNA [median, 2 (range, 0‐9)] and 100% (90/90) for tissue‐DNA [median, 4 (range, 1‐9)]. Most common alterations occurred in TP53 (38%), KRAS (28%), and PIK3CA (14%) for ctDNA vs TP53 (44%), CDKN2A/B (33%) and KRAS (29%) for tissue‐DNA. In 40 patients who had both ctDNA and tissue‐DNA sequencing, overall concordance was higher between ctDNA and metastatic site tissue‐DNA than between ctDNA and primary tumor DNA (78% vs 65% for TP53, 100% vs 74% for KRAS and 100% vs 87% for PIK3CA [But not statistical significance]). Among 80 patients who received systemic treatment, the molecularly matched therapeutic regimens based on genomic profiling showed a significantly longer progression‐free survival (hazard ratio [95%confidence interval], 0.60 [0.37‐0.99]. P = .047 [multivariate]) and higher disease control rate (61% vs 35%, P = .04) than unmatched regimens. Evaluation of ctDNA and tissue‐DNA is feasible in biliary tract cancers.