Outcomes of postmastectomy radiotherapy in immediate autologous versus implant-based breast reconstruction: a multi-institutional cohort study.

BACKGROUND

To compare late toxicities, cosmetic outcomes, and reconstruction failure in patients undergoing immediate autologous reconstruction (AR) versus implant-based reconstruction (IBR) followed by postmastectomy radiotherapy (PMRT).

METHODS

A multi-institutional retrospective cohort study (2013-2024) assessed patients undergoing mastectomy with immediate reconstruction and PMRT. Primary endpoints were reconstruction failure (loss or replacement of the index implant reconstruction, or total flap loss) and late toxicities, including contracture, fat necrosis, and cosmesis (Kroll scale).

RESULTS

113 patients were included (68 AR, 45 IBR). AR utilised deep inferior epigastric perforator flaps; IBR cohort consisted of 41 direct-to-implant procedures and four latissimus dorsi flaps combined with implants. Among available baseline variables, cohorts were broadly similar except that AR patients were slightly older. Reconstruction failure was analysed in all IBR patients; four IBR patients were not evaluable for subsequent capsular contracture and cosmetic assessment because of implant removal before late assessment. Reconstruction failure occurred exclusively in IBR (28.9% [13 of 45] vs. 0% [0/68] in AR; P < 0.001). Clinically significant firmness was observed in 46.3% (19/41) of IBR versus 14.7% (10/68) of AR patients (P < 0.001). Fat necrosis occurred in 16.2% of AR patients without flap loss. Good/Excellent physician-assessed cosmesis was more frequent after AR (83.8% vs. 36.6%; P < 0.001). Recurrence rates were comparable between cohorts.

CONCLUSIONS

AR was associated with higher reconstruction survival and more favourable physician-assessed cosmetic outcomes compared with predominantly direct-to-implant, subpectoral IBR after PMRT. For patients with a high probability of requiring PMRT, AR should be discussed early and strongly considered when clinically feasible.