Establishing oncological safety of autologous fat transfer for total breast reconstruction: Results from the multicentre BREAST-I and BREAST-II trials.

BACKGROUND

Autologous fat transfer (AFT) has gained popularity as a minimally invasive alternative for autologous breast reconstruction post-mastectomy. It offers aesthetic advantages and improvements in quality-of-life, though concerns persist regarding its oncological safety due to the presence of adipose-derived stem cells (ADSCs).

METHODS

This pooled follow-up analysis combined data from the multicentre randomised controlled BREAST-I trial and the nonrandomised clinical BREAST-II trial, including women who underwent total breast reconstruction with AFT between 2015 and 2025. The AFT-cohort was compared with a nationwide control group of breast cancer patients derived from the Netherlands Cancer Registry (IKNL), matched by inverse probability weighting. The primary outcome was overall survival (OS). Local and regional recurrences and distant metastases were not included in statistical analyses due to known underreporting in the national registry, but were descriptively assessed within the study cohort.

RESULTS

A total of 242 AFT-patients and 19936 controls were included. The mean follow-up time was 8.0 years for AFT and 6.9 years for controls. Ten-year crude OS was 97.6 % (95 % CI 95.5-99.7 %) for AFT and 75.7 % (95 % CI 74.7-76.8 %) for controls. After adjustment for confounders and immortal time bias, AFT was not associated with increased mortality (HR 0.34; 95 % CI 0.14-0.88; p = 0.025). Residual confounding and differences in follow-up intensity between cohorts constitute key study limitations.

CONCLUSIONS

In this pooled multicentre cohort with long-term follow-up, AFT for total breast reconstruction after mastectomy did not negatively affect mortality compared with national registry controls. These results support the oncological safety of AFT as a reconstructive technique. Future research should include larger cohorts and assess disease-free survival.