Intensity-modulated radiation therapy (IMRT) is associated with fewer acute and chronic toxicities than is the standard approach of whole breast irradiation (WBI) in patients with breast cancer, reported investigators.
In the recent study by radiation oncologist Frank A. Vicini, MD, of Michigan Healthcare Professionals/21st Century Oncology in Farmington Hills, Michigan, and colleagues, 335 patients with stage 0-IIB breast cancer underwent radiation therapy with either standard WBI using conventional wedge technique (S-WBI; 87 patients); WBI with IMRT using a typical treatment time (I-WBI; 93 patients); or WBI with IMRT using an accelerated treatment time (I-AWBI; 155 patients). Median follow-up was 11.0, 9.1, and 1.1 years, respectively.
Among all patients, I-WBI showed decreased incidences of grade 2+ acute radiation dermatitis and induration compared with I-AWBI (1% vs 23%) and S-WBI (1% vs 12%). I-WBI also was associated with lower rates of chronic edema compared with S-WBI patients (3% vs 13%).
Although larger-breasted women exhibited higher toxicity levels than did smaller-breasted women, larger-breasted women undergoing I-WBI had fewer acute toxicities than did larger-breasted women undergoing S-WBI in terms of grade 2+ dermatitis (0% vs 19%) and edema (7% vs 24%). Compared with larger-breasted I-WBI patients, more larger-breasted I-AWBI patients had radiation dermatitis (0% vs 38%).
Despite the increased acute radiation dermatitis seen in the large-breasted I-AWBI patients, “Our data support the increasing role of IMRT in delivering not only [WBI] but also [WBI] using an accelerated treatment time,” commented Vicini in a statement from the American Society for Radiation Oncology (ASTRO). The study results were published by ASTRO’s Practical Radiation Oncology (PRO) journal.