Study Quantifies Breast Shrinkage After T1 Tumor Lumpectomy

FRIDAY, April 4, 2025 (HealthDay News) — Patients with T1 tumors undergoing breast-conserving therapy/radiation therapy (BCT/RT) may lose about 20 percent of breast volume at one year, according to a study published in the April issue of Plastic and Reconstructive Surgery.

Miriam Becker, from the University of California in San Diego, and colleagues calculated breast volume changes for 113 patients (115 breasts) after T1 tumor lumpectomies. Volumes were calculated from mammograms from preoperative baseline to seven years after radiation. Changes over time were assessed, with subset analyses of tumor volume of the breast of 10 percent or less and greater than 10 percent (67 and 48 patients, respectively).

During surgery, patients lost 8.3 percent of breast volume. The researchers found that volume loss was 19.3 percent at one year after BCT/RT. Total volume loss was 26.6 percent by year 5. In addition to lumpectomy defects, five-year volume loss was 21.7 and 29.5 percent for tumor/breast volume greater than 10 percent or 10 percent or less, respectively. No significant difference was seen for volume loss between subgroups. Larger breast volume was a significant predictor of greater volume loss for all five years, followed by diabetes and smoking history.

“Larger breast size, diabetes, and smoking history may predict increased volume loss whether whole- or partial-breast radiation was administered, and treatment with cytotoxic chemotherapy may predict increased shrinkage in patients receiving whole-breast radiation,” the authors write.

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