Concurrent use of aromatase inhibitors and hypofractionated radiation therapy

To retrospectively assess the acute and long-term toxicity using aromatase inhibitors (AI) therapy concurrently with hypofractionated radiotherapy (HFRT) in breast cancer patients.

From November 1999 to October 2007, 66 patients were treated with breast HFRT and concurrent AI. In 63 patients (95.5%), HFRT delivered a total dose of 32.5 Gy to the whole breast within 5 wk (five fractions, one fraction per week). Other fractionations were chosen in three patients for the patients' personal convenience. A subsequent boost to the tumor bed was delivered in 35 patients (53.0%). Acute toxicities were scored according to the Common Toxicity Criteria for Adverse Events v3. Late toxicity was defined as any toxicity occurring more than 6 mo after completion of HFRT and was scored according to the Late Effects Normal Tissue Task Force-Subjective, Objective, Management and Analytic scale.

At the end of the HFRT course, 19 patients (28.8%) had no irradiation-related toxicity. Acute grade 1-2 epithelitis was observed in 46 patients (69.7%). One grade 3 toxicity (1.5%) was observed. With a median follow-up of 34 mo (range: 12-94 mo), 31 patients (47%) had no toxicity, and 35 patients (53%) presented with grade 1-2 fibrosis. No grade 3 or greater delayed toxicity was observed.

We found that AI was well tolerated when given concurrently with HFRT. All toxicities were mild to moderate, and no treatment disruption was necessary. Further prospective assessment is warranted.