ideasIdea

A ctDNA residual disease-guided adjuvant trial after gallbladder cancer resection

After surgery for bile duct or gallbladder cancer, a blood test for leftover tumour DNA picks out the people whose cancer will return with hazard ratios of 16 to 26 in two recent cohorts. Nobody has yet tested giving those people more than the standard capecitabine.

Tumour-informed ctDNA in the 2 to 12 week window after biliary resection was positive in 23 percent of 167 patients and carried a relapse-free survival hazard ratio of 15.86 (Malla 2026); in a 56-patient cohort the hazard ratio was 26 (Yu 2025). Gallbladder cancer recurs early and distantly after re-resection (Varshney 2025), which is the setting where a residual disease test could pick who gets escalation. The template exists in colon and bladder cancer (DYNAMIC, IMvigor011). A biliary trial would randomise ctDNA-positive patients after resection to capecitabine or gemcitabine-cisplatin with durvalumab, and could de-escalate ctDNA-negative T1b or T2a patients to observation.

Hypothesis

In resected gallbladder cancer with detectable ctDNA at 4 to 8 weeks, adjuvant gemcitabine-cisplatin plus durvalumab improves two-year recurrence-free survival over capecitabine by at least 15 percentage points; in ctDNA-negative early-stage disease, observation is non-inferior to capecitabine.

Rationale

Residual disease positivity is the strongest prognostic factor yet measured after biliary resection, and stronger than CA 19-9; adjuvant capecitabine's benefit is unproven in gallbladder cancer specifically.

Proposed test

Two-cohort randomised trial (escalation in ctDNA-positive, de-escalation in ctDNA-negative) nested in a national incidental cancer pathway, with tumour-informed assay from the resection specimen; about 400 patients over four years across a hepatobiliary network.

Maturity

early clinical

Who acts

research

Cost to try

Medium ($1M to $50M)

Years to first evidence

Bottlenecks it attacks

Dormant cells and minimal residual disease · After a 'successful' treatment, cells can sleep for years then relapse. We can barely detect them and cannot target them.
Trial design, endpoints and cost · A phase 3 trial takes years and hundreds of millions of dollars, and often answers a question that has already moved on.

Key papers

2top

real worldESMO Gastrointestinal Oncology 20260 citations

Real-world analysis of ctDNA and other biomarkers in patients with curatively resected stage I-III biliary tract cancer

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.

real worldJCO Precision Oncology 20259 citations

Detecting Early Recurrence With Circulating Tumor DNA in Stage I-III Biliary Tract Cancer After Curative 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.