Shorter course of radiation therapy after mastectomy found to be safe, effective

Liz Meszaros, MDLinx | May 03, 2017

After mastectomy, a 3-week course of radiation therapy is safe and effective, and may reduce treatment time by as much as 50%, according to results from a phase 2 study conducted by researchers from Rutgers Cancer Institute of New Jersey in New Brunswick, NJ, and published in the current online edition of the Journal of Clinical Oncology.


Post-mastectomy radiation therapy

Phase 2 study results show shorter course of therapy is feasible, safe, and researchers plan to conduct a phase 3 trial.

Typically, targeted radiation may be administered to patients over 5 to 6 weeks due to a concern that cancer cells could stay in the chest wall and lymph node regions after mastectomy.

“Receiving radiation for that long of a period becomes a quality of life issue for many patients. This includes the inconvenience of frequent travel to the treatment facility, as well as fatigue and other common side effects that can cause lost time at work and other challenges,” said senior investigator Bruce G. Haffty, MD, professor and chair, Department of Radiation Oncology, Rutgers Cancer Institute, Rutgers Robert Wood Johnson Medical School, Piscataway Township, NJ, and Rutgers New Jersey Medical School, Newark, NJ.

Dr. Haffty and colleagues studied a short course of hypofractionated postmastectomy radiation therapy (PMRT) that was administered over 15 treatment days, comparing with a traditional 6-week course of treatment.

In 67 women with stage II to stage IIIa breast cancer, they delivered PMRT (36.63 Gy in 11 fractions of 3.33 Gy) over 11 days to the chest wall and the draining regional lymph nodes. This was followed by an optional mastectomy scar boost (4 fractions of 3.33 Gy). The primary endpoint of the study was any grade 3 or higher toxicities.

After a median follow-up of 32 months, researchers observed no grade 3 toxicities and 29 grade 2 toxicities, of which grade 2 skin toxicity was the most common (24%). Two patients (3%) had isolated ipsilateral chest wall tumor recurrences.

The 3-year estimated local recurrence-free survival was 89.2% (95% CI: 0.748, 0.956), and 3-year estimated distance recurrence-free survival was 90.3% (95% CI: 0.797, 0.956).

In all, 41 patients underwent chest wall reconstructions, and 3 had expanders removed for infection prior to radiation treatment.

The total rate of implant loss or failure was 24%, and unplanned surgical correction rate was 8%. This combined for a total complication rate of 32%.

“While shorter courses of radiation therapy have been adopted in patients receiving radiation therapy to the breast alone after lumpectomy, there has not been adoption of shorter courses of treatment to the chest wall and lymph nodes after mastectomy. This trial demonstrated the safety of this shorter course approach in a prospective phase II study,” concluded Dr. Haffty.

Based on these results, these researchers have designed and will conduct a cooperative group phase 3, prospective, randomized trial of conventional versus hypofractionated PMRT through the Alliance Cooperative Group, with Dr. Haffty and current study investigators Matt Poppe of the Huntsman Cancer Institute and Atif J. Khan of Memorial Sloan Kettering Cancer Center leading the effort.