Postmastectomy radiation therapy (PMRT) can damage a reconstructed breast, yet many patients cannot skip it. That leaves plastic surgeons with two questions: when to place the flap, and which flap to use in patients with low body mass index (BMI).
Dr. Sik Namgoong, associate professor of plastic surgery at Korea University College of Medicine, addressed both in his talk When and How to Cross the Radiation Valley, part of the session Beyond the DIEP: Autologous Breast Reconstruction in Low-BMI Patients Undergoing PMRT, at Plastic Surgery The Meeting 2026, organized and hosted by the American Society of Plastic Surgeons (ASPS), in Houston, Texas.
He opened with 2 cases. The first patient had a mastectomy with immediate flap reconstruction, followed by chemotherapy and radiation. The second received an implant before radiation and later developed severe pain and tightening. His team removed the implant and damaged tissue, then rebuilt the breast with a deep inferior epigastric perforator (DIEP) flap. Both cases showed how radiation can harm reconstructed tissue, causing problems such as tissue loss or implant tightening.
"But here's the problem: we cannot take radiation away.... So how do we reconstruct, and when do we reconstruct?" he said. For patients who need PMRT, he prefers a flap over an implant.
Why He Prefers the Flap Last
Radiation injures skin and soft tissue at the cellular level, and the tissue never fully recovers, Dr. Namgoong noted. His preferred approach is delayed reconstruction in 3 steps: excise all compromised, irradiated tissue; rebuild with healthy tissue; and aim for a more durable result with less necrosis, fibrosis, and contracture.
Immediate Reconstruction and Low BMI
After national insurance in Korea began covering breast reconstruction in 2015, the reconstruction rate rose from 19% to 53%, and immediate reconstruction rose from about 4% to 52%. Most of his patients prefer immediate reconstruction, so the flap often goes in before radiation. Anticipating shape change and about 12% to 15% flap shrinkage after PMRT, he oversizes the flap, then balances later with mastopexy and serial fat grafting supplemented with stromal vascular fraction.
Low BMI changes the equation. When the abdomen cannot supply enough tissue, the lumbar artery perforator (LAP) flap keeps its volume, he reported. He ranked the DIEP flap first, with the LAP flap a close second.
He closed with his principle: "When radiation is inevitable, timing matters. When tissue is limited, flap selection matters even more. For me, the goal is simple: replace compromised tissue with healthy tissue, at the right time, using the right flap."
Key takeaway: Dr. Namgoong prefers delayed flap reconstruction after excising irradiated tissue. When immediate reconstruction comes first, he oversizes the flap to allow for about 12% to 15% shrinkage, and he considers the LAP flap when low BMI limits abdominal tissue.
Abbreviations: PMRT, postmastectomy radiation therapy; BMI, body mass index; DIEP, deep inferior epigastric perforator; LAP, lumbar artery perforator.