Shorter course of radiation after mastectomy does not compromise breast reconstruction
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Key takeaways:
- A shorter radiation therapy regimen conferred similar outcomes as standard of care for women undergoing breast reconstruction.
- Autologous reconstruction reduced complication risk compared with implant alone.
Women who want breast reconstruction after mastectomy can undergo a shorter radiation therapy regimen without significantly increasing their risk for complications, according to results of a randomized phase 3 trial.
Patients treated on a schedule 2 weeks shorter than standard of care had similar rates of complications and recurrence, findings presented during American Society for Radiation Oncology Annual Meeting showed.
“Hypofractionated post-mastectomy radiation therapy with reconstruction should become the new standard of therapy,” Matthew M. Poppe, MD, FASTRO, physician and investigator for Huntsman Cancer Institute and professor of radiation oncology at University of Utah, said during a press briefing. “This change will improve the lives of patients with breast cancer.”
Background and methods
More than 313,510 new breast cancer cases will be diagnosed in the U.S. this year, according to American Cancer Society estimates.
More than 100,000 women with breast cancer annually undergo mastectomies in the U.S., and about 50% choose to have breast reconstruction, according to study background.
A 5-week course of radiation is standard for women with intermediate- or high-risk breast cancer who undergo mastectomy. However, women with earlier-stage disease can undergo shorter treatment schedules.
Many women decline radiation because of cost or time constraints, Poppe said.
“Radiation therapy after mastectomy saves lives,” Atif J. Khan, MD, director of breast radiotherapy services and radiation oncologist at Memorial Sloan Kettering Cancer Center, said in a press release. “Patients shouldn’t have to choose between radiation or no radiation based on their desire for reconstruction, or because they can’t take 6 weeks out of their lives.”
Poppe, Khan and colleagues evaluated whether women with unilateral invasive breast cancer planning reconstruction could undergo a shorter radiation regimen without increasing risk for complications.
Researchers enrolled 880 participants (median age, 49 years; 51% received neoadjuvant chemotherapy) across 209 cancer centers in the U.S. and Canada from 2018 to 2021.
Investigators randomly assigned patients to standard radiation therapy (25 fractions across 5 weeks; 50 Gy total) or a shorter schedule (16 fractions across 3 weeks; 42.56 Gy total).
Occurrence of complications — including wound healing, readmission, capsular contracture, unplanned reoperation and reconstruction failure — served as the primary endpoint.
Results and next steps
In all, 650 women completed reconstruction. A higher percentage had delayed reconstruction than immediate reconstruction (55% vs. 45%) and implant alone vs. autologous reconstruction plus implant (49% vs. 41%).
In the intent-to-treat cohort of 825 participants, women assigned the shorter schedule had a statistically noninferior rate of complications as those assigned the standard schedule (14% vs. 12%; Z = 3.373; P = .0004) after 24 months.
“We expected a complication rate of 25% to 35% based on prior, single institution studies of patients who received reconstructive surgery and radiation,” Khan said. “It was very exciting to see a complication rate that was nearly half what we anticipated.”
Independent of radiation therapy schedule, autologous reconstruction appeared associated with reduced risk for complications compared with implant alone (8.7% vs. 15.5%; P = .0043).
“There’s actually about six [subgroups],” Poppe said. “It looks like a two-stage procedure — you put in a temporary tissue expander and then you reconstruct the breast later — causes higher complications. That shouldn’t surprise anyone because it’s two opportunities for problems [and] two opportunities for infection in wound healing. The other thing is when you use an implant and no autologous tissue, it also increases complications, which also is somewhat intuitive because it’s not your own native tissue and it’s not vascularized.”
At 36 months, results showed comparable rates of cancer recurrence among women assigned the shorter radiation schedule and the standard schedule (1.5% vs. 2.3%). Typical recurrence for patients with high-risk disease who undergo mastectomy but do not receive radiation ranges from 20% to 30%, Khan said.
Rates of acute or late toxicities did not differ significantly based on radiation regimen.
“The majority of my patients live 2 to 5 hours away from our cancer hospital,” Poppe said in a press release. “Taking 5 or 6 weeks of time, uprooting your family or leaving your business behind to move closer to the cancer center — even though it’s important for survival — can be out of reach for a lot of patients. When I tell people they can do 3 weeks of radiation instead of 6 weeks, you can see their relief.”
Patient-reported outcomes and photographic assessments will add more context to the results, Poppe said.
“We’re really reaching a critical mass of data that allows us to embrace hyprofractionated or shorter-course schedules for our patients who undergo breast reconstruction and require post-mastectomy radiation,” ASTRO expert Rachel Jimenez, MD, professor of radiation oncology at Harvard Medical School, chair for quality and safety in the department of radiation oncology at Massachusetts General Hospital, and vice chair of the ASTRO post-mastectomy radiation therapy guideline update, said during a press briefing.
References:
- ASTRO. Post-mastectomy radiation therapy can be shortened by nearly half for patients planning breast reconstruction (press release). Published Sept. 30, 2024. Accessed Sept. 30, 2024.
- Poppe MM, et al. Abstract 1. Presented at: ASTRO Annual Meeting; Sept. 29-Oct. 2, 2024; Washington, DC.
Perspective
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Andrew Vassil, MD
A large-scale study, the RT CHARM trial, has shown that a shorter course of radiation therapy following mastectomy does not increase complications for patients undergoing breast reconstruction.
Traditionally, patients undergoing breast reconstruction after mastectomy have been excluded from studies testing shorter radiation regimens due to concerns that higher doses could harm reconstruction outcomes. However, the RT CHARM trial showed the shortened treatment schedule did not lead to more complications. Importantly, complication rates were nearly half of what had been anticipated, based on previous studies. In terms of cancer recurrence, both groups had similar outcomes: 1.5% of patients in the shorter treatment arm and 2.3% in the standard arm experienced recurrence within 3 years. These findings are in-line with recently published FABREC trial.
This research supports the feasibility of shorter radiation courses for patients with breast cancer, offering a more accessible option that saves time and resources. With a median follow-up of 5 years, the findings are expected to encourage more centers to adopt this accelerated treatment regimen, improving both survival rates and quality of life for patients.
Reference:
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Poppe MM, et al. Abstract 1. Presented at: ASTRO Annual Meeting; Sept. 29-Oct. 2, 2024; Washington, DC.
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