The addition of stereotactic body radiotherapy (SBRT) to systemic chemotherapy did not demonstrate an improved progression-free survival (PFS) among patients with locally advanced, inoperable cholangiocarcinoma. However, more mature data is needed to determine whether there is an overall survival benefit.

These results will be presented by Maria A Hawkins, MD, University College London, United Kingdom, at the 2024 American Society of Clinical Oncology (ASCO) Annual Meeting in Chicago, Illinois.

The multicenter, randomized, phase 2 ABC-07 trial enrolled 69 patients with inoperable, locally advanced cholangiocarcinoma. Those patients who experienced no progression after 4 cycles of gemcitabine and cisplatin were randomized on a 2-to-1 basis after completing 6 cycles, to receive either SBRT (n = 45) or 2 additional cycles of gemcitabine-cisplatin (n = 24). The primary end point was PFS with secondary end points including OS, toxicity, and patterns of failure.

With a median follow-up duration of 20.7 months, the median PFS (from randomization) was 8.6 months in the SBRT arm and 9.0 months in the gemcitabine-cisplatin alone arm (hazard ratio [HR], 1.00; 95% confidence interval [CI], 0.58 to 1.70; P = .989). The first PFS events were local in 16% of patients and metastatic relapses in 53% of patients in the SBRT arm. In the chemotherapy alone group, the first PFS events were local in 29% and metastatic relapses in 29%. The median OS (from randomization) was 19.4 months in the SBRT arm vs 14.2 months in the chemotherapy alone arm (HR, 0.79; 95% CI, 0.41 to 1.51; P = .47).

Grade ≥3 adverse events were observed in 73% of patients in the SBRT arm and 88% of patients in the chemotherapy alone arm. There was 1 instance of grade 3 duodenal hemorrhage, and 1 death due in the SBRT arm. The primary causes of death were disease (44% in the SBRT arm vs 46% in the chemotherapy alone arm), sepsis (11% vs 13%), and hepatic failure (0% vs 13%).

The study authors concluded that there was while SBRT “did not show a PFS advantage” over chemotherapy alone, there was “a longer median OS time and better primary tumor control” without additional safety concerns. “However,” they added, “more mature survival data is still needed.”

Source:

Hawkins MA, Valle JW, Wasan HS, et al. Addition of stereotactic body radiotherapy (SBRT) to systemic chemotherapy in locally advanced cholangiocarcinoma (CC) (ABC-07): Results from a randomized phase II trial. Presented at the ASCO Annual Meeting. May 31 – June 4, 2024; Chicago, IL. Abstract #4006