Hypofractionated Radiation Safe for Breast Reconstruction

WASHINGTON, DC — Radiation oncologists can feel confident offering hypofractionated treatment regimens to treat breast cancer in patients who are planning breast reconstruction after mastectomy, following new findings presented at the American Society for Radiation Oncology (ASTRO) annual meeting.

Over the past decade, radiation oncologists have moved toward hypofractionated regimens for breast cancer to ease the burden of treatment. The benefit of shorter radiation treatment durations at higher doses is less time in the clinic and lower out-of-pocket costs for patients. For those who live far away, this time- and cost-saving approach could make the difference between having radiation or forgoing it. 

Although trials have shown equivalent oncologic outcomes with hypofractionated and conventional regimens, women who opt for breast reconstruction after mastectomy have not been offered hypofractionation out of concern that the higher radiation doses might compromise reconstruction outcomes.

Findings from the phase 3 RT-CHARM trial have now laid that concern to rest. 

“Now we have robust data from hundreds of academic and community centers and from patients with any type of reconstruction that clearly show the safety and effectiveness of short course radiation,” principal investigator Matthew Poppe, MD, professor of radiation oncology at the University of Utah, Salt Lake City, said in an ASTRO press release. “The results of this trial show we can safely reduce treatment time for these patients to 3 weeks, without compromising their reconstruction.”

In the trial, 898 women were randomized equally to either a conventional regimen of 25 fractions over 5 weeks or a hypofractionated regimen of 16 fractions over 3 weeks. 

Women in the trial had unilateral invasive pT0-2, pN1-2, or pT3N0 breast cancer. Patients received treatment at 209 centers across the US and Canada, and they were a median of 46 years of age. The total radiation dose was 50 Gy in the conventional regimen arm and 42.56 Gy in the hypofractionated regimen arm.

Among the 650 patients who completed reconstruction, 59% had implants alone and 41% had autologous reconstruction with or without implants. Just over half had delayed reconstruction at a mean of 265 days, whereas the rest had immediate reconstruction. 

At 2 years, the incidence of reconstruction complications was 14.2% with shorter-course radiation vs 12.2% with conventional dosing, regardless of reconstruction type and whether women had immediate or delayed reconstruction (P for noninferiority = .0004).

Poppe and colleagues also found no statistically significant differences in the incidence of reconstruction wound healing problems, hospital readmissions, unplanned reoperations, reconstruction failures, or capsular contractures. 

Within 3 years of treatment, locoregional recurrence rates were 1.5% in the hypofractionated regimen group vs 1.9% of those in the conventional regimen group.

Patient-reported outcomes and photographic assessments are pending. 

Implant and two-stage reconstructions with tissue expansion had higher complication rates, including infections and wound healing issues. Poppe said surgical teams and patients should be aware of the issue. 

Overall, the results highlight that hypofractionation “should really become the new standard of care,” he told the ASTRO audience. 

With the trial results in hand, Poppe now offers hypofractionated regimens to his patients undergoing breast reconstruction, many of whom live 2-5 hours away. When they hear they can be treated in 3 weeks instead of 5 or 6, “you can see their relief,” he said. 

Study discussant Rachel Jimenez, MD, associate professor of radiation oncology at Harvard Medical School, Boston, told Medscape Medical News that she hopes hypofractionation will become standard of care in reconstruction after mastectomy. 

Combined with smaller studies with similar conclusions, “we’re really reaching a critical mass of data that allows us to embrace hypofractionated or shorter course schedules for patients who undergo breast reconstruction,” said Jimenez, who is also vice-chair of ASTRO’s forthcoming postmastectomy radiotherapy guidelines update. 

The research was funded by the National Cancer Institute. Poppe and Jimenez had no relevant disclosures. 

M. Alexander Otto is a physician assistant with a master’s degree in medical science and a journalism degree from Newhouse. He is an award-winning medical journalist who worked for several major news outlets before joining Medscape. Alex is also an MIT Knight Science Journalism fellow. Email: aotto@mdedge.com