ASTRO 2021: Novel Once-Daily Partial Breast Irradiation Regimen Focus of Phase II Trial
Posted: Tuesday, November 2, 2021
According to research presented at the 2021 American Society for Radiation Oncology (ASTRO) Annual Meeting (Abstract 1026), a once-daily regimen of accelerated partial breast irradiation may result in superior cosmetic and quality-of-life outcomes for patients with breast cancer versus daily whole-breast irradiation. Although twice-daily accelerated partial breast irradiation may result in improved function versus whole-breast irradiation, once-daily exposure may lead to superior long-term cosmetic outcomes.
“Daily external-beam partial-breast irradiation with 10 or fewer fractions merits further prospective evaluation,” noted Jay Paul Reddy, MD, PhD, of MD Anderson Cancer Center in Houston, and colleagues.
The study enrolled 149 women (aged 50 and older) between 2017 and 2018 who had ductal carcinoma in situ or early invasive estrogen receptor–positive breast cancer. Patients received 35 Gy in 10 daily fractions, a regimen known as OPAL; those with margins of less than 2 mm (n = 26) received an additional boost of 9 Gy in 3 daily fractions. A comparison cohort of 176 patients was identified from a previous trial in which outcomes from whole-breast irradiation plus boost were investigated.
At a median follow-up of 2 years, 14.1% of patients receiving OPAL and 71.0% of the comparison cohort experienced toxicity at grade 2 or higher within 6 months of undergoing partial-breast irradiation. Patients undergoing OPAL experienced less fatigue (8% vs. 16%), hyperpigmentation (18% vs. 30%), breast edema (0% vs. 9%), superficial fibrosis (18% vs. 31%), deep fibrosis (6% vs. 13%), nipple areolar changes (6% vs. 17%), and breast atrophy (19% vs. 35%) than those in the comparison cohort.
Patients who received OPAL reported excellent or good cosmetic outcomes at a higher rate than did those in the comparison cohort (93% vs. 77%). Improved patient- and physician-reported cosmetic results, functional status, and breast pain were associated with the OPAL regimen.
Disclosure: For full disclosures of the study authors, visit astro.org.