Single-Institution Experience Indicates Improved Outcomes With Higher Radiotherapy Doses in Inoperable Intrahepatic Cholangiocarcinoma


Key Points

  • A radiotherapy biologic equivalent dose > 80.5 Gy appears to be ablative in inoperable disease.
  • Higher doses as a continuous variable were associated with improved local control and overall survival.

In a single-institution retrospective analysis reported in the Journal of Clinical Oncology, Tao et al found that use of higher radiotherapy doses was associated with prolonged local control and overall survival in patients with inoperable intrahepatic cholangiocarcinoma. Overall survival was markedly prolonged in patients receiving a biologic equivalent dose > 80.5 Gy.

Study Details

The study involved 79 consecutive patients with inoperable disease treated with definitive radiotherapy at The University of Texas MD Anderson Cancer Center from 2002 to 2014. Patients had a median tumor size at diagnosis of 7.9 cm (range = 2.2–17 cm), and 89% received systemic chemotherapy before radiotherapy. Radiotherapy doses were 35 to 100 Gy (median = 58.05 Gy) in 3 to 30 fractions for a median biologic equivalent dose of 80.5 Gy (range = 43.75–180 Gy).

Median follow-up among patients alive at the time of analysis was 33 months (range = 11–93 months). Median overall survival from diagnosis was 30 months, and 3-year overall survival was 44%.

Survival and Local Control

Median overall survival was longer among patients receiving a biologic equivalent radiation dose higher than vs lower than the conventional dose of 50.4 Gy (43 vs 23 months, P = .01). Three-year overall survival was 73% in patients receiving a biologic equivalent dose > 80.5 Gy vs 38% in those receiving lower doses (P = .017); median overall survival was not reached vs 27 months (P = .002). Three-year local control rates were 78% vs 45% (P = .04). Biologic equivalent dose as a continuous variable was significantly positively associated with both local control (P = .009) and overall survival (P = .004). There were no significant treatment-related toxicities.

The investigators concluded: “Delivery of higher doses of [radiotherapy] improves [local control] and [overall survival] in inoperable [intrahepatic cholangiocarcinoma]. A [biologic equivalent dose] greater than 80.5 Gy seems to be an ablative dose of [radiotherapy] for large [intrahepatic cholangiocarcinomas], with long-term survival rates that compare favorably with resection.”

Christopher H. Crane, MD, of The University of Texas MD Anderson Cancer Center, is the corresponding author for the Journal of Clinical Oncology article.

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