Trials and papersBiliary tract cancer (cholangiocarcinoma)

The IHC 3+ subgroup result is why the tumour-agnostic label is written at 3+ and not 2+, and why a gallbladder cancer with a strong HER2 stain now has two on-label choices (zanidatamab, trastuzumab deruxtecan) after chemotherapy. Lung toxicity again ran higher than in breast cancer.

A direct check of the HERIZON-BTC-01 testing algorithm in routine pathology: IHC 3+ can stand alone, 2+ needs ISH, and the low-level amplification in weakly stained tumours is the group where HER2 drugs are least likely to help.

For gallbladder cancer the points that matter are that HER2 can disappear under HER2-directed pressure, that SMAD4 co-mutation predicts a worse response, and that sequencing at progression, not just at diagnosis, may be needed to guide the next line.

For someone offered the test, these are the numbers that describe what a result means in an NHS population: about 1 in 100 tests came back positive each year, between 46 and 58 in 100 positives were cancer, and a negative result left about 1 in 100 with an undetected cancer within the year. The test found between a quarter and a third of all cancers diagnosed in a screening round, and about half to two thirds of the 12 cancer types it was designed to find. Whether finding them this way reduces late-stage diagnoses is the primary question, and this paper says only that the answer was no; the primary-endpoint paper had not appeared on Europe PMC by 23 September 2026.

Together with the JCO Precision Oncology cohort this makes residual disease testing in biliary cancer prognostic to the same degree as in colon cancer. Nobody has yet shown that acting on it helps; that is the trial gap the ideas on this page name.

NCCN is the source of the category grades quoted on the gallbladder cancer page; the adjuvant section leans on BILCAP for capecitabine and on SWOG S0809 for chemoradiation after margin-positive or node-positive resection.

Very wide confidence intervals from a small cohort, but the direction matches the larger 2026 analysis. Gallbladder cancer recurs early and distantly after re-resection, which is exactly the setting where a residual disease test could pick who gets more than capecitabine.

The tail of long survivors is the case for chemo-immunotherapy in gallbladder cancer, where the median gain is under two months. Who lands in that tail is still unknown; no biomarker in the trial predicts it.