Study Highlights Breast Shrinkage as Long-Term Effect of Breast-Conserving Therapy - Video

For women with early-stage breast cancer, breast-conserving therapy (BCT) including radiation therapy (RT) leads to progressive reduction in breast size over time, reports a study in the Plastic and Reconstructive Surgery®, the official medical journal of the American Society of Plastic Surgeons (ASPS).

Breast-conserving therapy – consisting of limited surgery (lumpectomy) and RT – is the preferred treatment for many women with early-stage breast cancer. It offers survival rates similar to those of mastectomy, with more favorable physical, psychological, and quality of life outcomes.

However, RT has adverse effects on breast tissue, including breast shrinkage due to radiation-induced tissue atrophy and fibrosis. While this long-term side effect is well-recognized, there are few data on the extent or time course of breast volume loss after BCT.

The authors measured changes in breast volume in 113 patients who underwent BCT/RT for early-stage (T1) breast cancer between 2005 and 2023. Measurements were made using mammograms obtained before and after BCT and up to five years later. The researchers also examined the impact of initial breast size and other factors on volume loss.

Reflecting the size of the tumor, breast volume decreased by an average of 9.2% after lumpectomy. Breast volume continued to decrease over time, even after the immediate side effects of radiation resolved. After one year, the average decline in breast volume was 19.3%, in addition to the tissue removed at surgery.

Women with larger breasts and relatively smaller tumor volumes (measuring less than 10% of breast volume) had greater total breast shrinkage: 29.5%, compared to 21.7% for those with smaller breasts. Other factors associated with greater volume loss included smoking, diabetes, and receiving cytotoxic chemotherapy in addition to RT.

The study provides new evidence on breast shrinkage after BCT. Expected breast shrinkage is approximately 20% within the first year, progressing to about 26% by five years. Especially with the growing emphasis on patient satisfaction in evaluating the outcomes of breast cancer treatment, the findings highlight the need to discuss long-term changes in breast volume in patients receiving undergoing BCT/RT.

The authors discuss key areas for further research, including the effects of different treatment techniques on breast volume changes and the need for more objective approaches to measuring breast volume.

Ref: Becker, Miriam, Reese, McKay et al. A Quantitative Evaluation of the Effects of Radiation Therapy on the Postsurgical Breast. Plastic and Reconstructive Surgery 155(4):p 595-605, April 2025. | DOI: 10.1097/PRS.0000000000011732