Ablative radiotherapy (A-RT) may be underused in patients with unresectable intrahepatic cholangiocarcinoma (ICC) in the United States, according to a large study published in Cancer.

Researchers found that liver-directed RT was used in 13% of the patients analyzed, and RT use remained stable from 2004 to 2018. 

Four percent of patients had RT dose information available, and 27% of this group received A-RT. Overall survival (OS) was significantly longer with A-RT than with conventional RT (Conv-RT).


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For this study, researchers analyzed data from 27,571 patients with localized or metastatic unresected ICC. The patients were diagnosed between 2004 and 2018 and entered into the National Cancer Database.

The use of liver-directed RT, with or without chemotherapy, was low. The most common treatment was chemotherapy without RT (45%), followed by treatment without chemotherapy or RT (42%). Patients also received liver RT with chemotherapy (9%), liver RT without chemotherapy (4%), and other local therapies alone (2%). 

A total of 3555 patients (13%) received liver-directed RT, and 1112 of the patients had information on RT dose available. RT with a biologically effective dose (BED10) of at least 80.5 Gy was considered A-RT, and lower doses were considered Conv-RT.

Of the 1112 patients with dosing information available, 73% received Conv-RT. The median BED10  was 53 Gy (in 20 fractions) for Conv-RT and 100 Gy (in 5 fractions) for A-RT.

Overall, the use of liver-directed RT remained constant over time (P =.715). However, the proportion of RT recipients who received A-RT increased over time, from 5% in 2004 to 48% in 2018 (P <.001).

In a multivariate analysis, the odds of using A-RT were lower for patients with stage III disease (odds ratio [OR], 0.33; 95% CI, 0.19-0.56) or stage IV disease (OR, 0.37; 95% CI, 0.23-0.59) and for patients who received chemotherapy (OR, 0.54; 95% CI, 0.37-0.79).

Among patients who had undergone liver-directed RT, A-RT was significantly associated with prolonged survival. The median OS was 23.7 months with A-RT and 12.8 months with Conv-RT (P <.001). 

The 1-year OS rate was 75% with A-RT and 53% with Conv-RT. The 2-year OS rates were 49% and 28%, respectively. The 3-year OS rates were 28% and 15%, respectively.

“[T]his is the first report of A-RT use across the United States and highlights significant areas of deficit in its use,” the researchers wrote. “[O]ur results suggest that liver-directed RT and, more specifically, A-RT, should be considered for patients with unresectable ICC.”

Disclosures: Some study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of disclosures.

Reference

De B, Tran Cao HS, Vauthey J-N, et al. Ablative liver radiotherapy for unresected intrahepatic cholangiocarcinoma: Patterns of care and survival in the United States. Cancer. Published online April 13, 2022. doi:10.1002/cncr.34223

This article originally appeared on Cancer Therapy Advisor