Accelerated radiation after mastectomy reduces treatment time without reducing effect

Hypofractionated radiation therapy (HFRT) after mastectomy in women with intermediate-stage high-risk breast cancer was as good as conventional fractionated radiation therapy (CFRT), but it reduced treatment time from five weeks to three weeks, according to research presented at the American Society for Radiation Oncology (ASTRO) annual meeting, held in San Diego, CA.

“Clinicians have seen clear benefits with accelerated radiation therapy to the whole breast after breast-conserving surgery, but questions remain about its safety and effectiveness with treating nodal regions,” explained one of the study’s lead authors Shulian Wang, MD, a radiation oncologist at the Chinese Academy of Medical Sciences, in Beijing, China.

To that end, Dr. Wang and colleagues conducted a phase 3 clinical trial that included 820 high-risk patients, most with stage III breast cancer (93.9%). Following mastectomy, patients were randomly assigned to receive either accelerated (ie, HFRT) external beam radiation therapy (43.5 Gy in 15 daily fractions for three weeks) or conventional radiation therapy (50 Gy in 25 daily fractions for five weeks) to the chest wall and supraclavicular nodal region.

After five years of follow-up, outcomes in patients in the HFRT group were not significantly different from those in the CFRT group. Locoregional recurrence occurred in 8.3% of the accelerated group and in 8.1% of the conventional group. Distant metastases developed in 23.2% of the HFRT group and in 26.2% of the conventional group.

Overall survival at five years was 83.2% in patients who received accelerated treatment and 85.6% in those who received standard treatment. Disease-free survival was 74.6% in the HFRT group and 70.7% in the CFRT group.

“This trial demonstrates that we can safely accelerate adjuvant radiation therapy and reduce treatment time by two weeks…while preserving high rates of tumor control and tolerability,” Dr. Wang said. “This option makes treatment more convenient for patients, reduces medical expenses, and allows providers to treat more patients with limited resources.”

The incidences of treatment-related side effects—including symptomatic radiation pneumonitis, lymphedema, and shoulder disorder—were also similar between the two groups, although patients in the accelerated treatment group had less grade 3 acute skin toxicity than those in the standard treatment group (3.5% vs 7.8%).

Patients also experienced fewer side effects following accelerated therapy, indicating that HFRT following mastectomy is a safe and effective treatment for locally advanced disease, researchers concluded.

“The accelerated approach also has practical value for patients,” Dr. Wang said. “With fewer treatment sessions, patients spend less time away from work and family, enjoy lower transportation costs, and, as our findings show, experience fewer side effects.”