Accelerated Radiation Therapy Course is Non-Inferior to Traditional Radiation in Patients Undergoing Breast Reconstruction

New research demonstrates that an accelerated course of radiation therapy does not increase complications for patients who receive breast reconstruction following a mastectomy. According to the authors, the RT CHARM study is the first multi-institutional international study to demonstrates that a shorter course of post-mastectomy radiation combined with breast reconstruction is both safe and effective.¹

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Breast cancer is the second most frequently diagnosed cancer for women in the US, and approximately 40% of patients with breast cancer receive mastectomies. Among that group, the majority also undergo reconstructive breast surgery. The accelerated radiation therapy could cut from 25 to 16 treatment sessions and make post-mastectomy radiation a more accessible option for patients.¹

“Over the past 10 years, we’ve tried to move all patients who need breast radiation to a shorter, more convenient schedule,” said principal study investigator Matthew M. Poppe, MD, FASTRO, professor of radiation oncology at the University of Utah in Salt Lake City, in a news release. “But patients after mastectomy who were planning breast reconstruction were the 1 group where we didn’t have sufficient data to support shorter courses. Now, the results of this trial show we can safely reduce treatment time for these patients to 3 weeks, without compromising their reconstruction.”¹

RT CHARM (NCT0341497) was a randomized phase 3 trial in which women with unilateral invasive breast cancer who were planning delayed or immediate breast reconstruction and post-mastectomy radiation were randomly assigned to receive either hypofractionated radiation therapy (which was administered daily on weekdays for 3-4 weeks) or traditional radiation therapy (which was administered daily on weekdays for 5-6 weeks). A total of 898 patients from 209 North American centers were enrolled from 2018 to 2021. The primary end point was the rate of breast reconstruction complications, which was measured at 24 months.^2,3

Among the 572 patients who completed reconstruction, 45% had immediate and 55% had delayed, with an average 265-day delay. Further, 57% of patients had implant alone and 43% had autologous +/- implant. At 24 months, reconstruction complications were present in about 14% (n = 59) patients with hypofractionation compared with 11.7% (n = 47) with conventional post-mastectomy reconstruction (2.3%; 95% CI = 2.2%-6.9%; P = .0005). Additionally, complication rates decreased with autologous versus implant only reconstruction (OR: 0.504; P = .0059), and this was observed regardless of which radiation therapy patients received.³

Further, acute and late toxicity rates were not statistically significant between arms. A total of 36 local or regional recurrences occurred in about 1.5% (95% CI = 0.7%-3.3%) of hypofractionated and 2.3% (95% CI = 1.1%-4.6%) of conventional patients.³

“We expected a complication rate of 25% to 35% based on prior, single institution studies of patients who received reconstructive surgery and radiation. It was very exciting to see a complication rate that was nearly half what we anticipated,” said senior study author Atif J. Khan, MD, radiation oncologist, Memorial Sloan Kettering Cancer Center, in the news release. “Radiation therapy after mastectomy saves lives. 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.”¹

The authors noted that without radiation therapy, the typical recurrence rate following mastectomy in patients with high-risk disease is about 20% to 30%. With data presenting that the shorter radiation therapy is a safe and effective option with less observed complications, the investigators were optimistic that the shorter radiation regimen will be of interest to patients who find the longer schedules inaccessible and daunting.¹

“The majority of my patients live 2 to 5 hours away from our cancer hospital. 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, it 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,” said Poppe in the news release. “There’s been a slow start to moving to shorter treatment courses after mastectomy, even with no reconstruction. But 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.”¹

REFEFERENCES

1. American Society for Radiation Oncology. Post-mastectomy radiation therapy can be shortened by nearly half for patients planning breast reconstruction. News release. September 30, 2024. Accessed September 30, 2024. https://www.eurekalert.org/news-releases/1059403

2. Hypofractionated Radiation Therapy After Mastectomy in Preventing Recurrence in Patients With Stage IIa-IIIa Breast Cancer. ClinicalTrials.gov identifier: NCT0341497. Updated April 9, 2024. Accessed September 30, 2024. https://clinicaltrials.gov/study/NCT03414970

3. Poppe MM, Le-Rademacher J, Haffty BG, et al. A Randomized Trial of Hypofractionated Post-Mastectomy Radiation Therapy (PMRT) in Women with Breast Reconstruction (RT CHARM, Alliance A221505). IJROBP. 2024;120(2, Supplement):S11. doi:10.1016/j.ijrobp.2024.07.002