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Abstract Background. Fat grafting during or after mastectomy could promote the regeneration of irradiated tissues, thus improving tissue softness, increasing patient comfort and ameliorating quality of life. However, there are no conclusive data about the oncological safety of fat grafting, especially in terms of risk of tumor recurrences. The most appropriate timing of adipose tissue transplant is also debated, especially in patients with locoregional breast cancer (BC) recurrence undergoing salvage mastectomy and implant-based breast reconstruction after breast conserving surgery and radiotherapy. Methods. We conducted a prospective, multicentric Italian study to investigate the oncological safety of fat grafting between June 2007 and March 2022. One hundred sixty-three patients who had previously received radiotherapy, either as adjuvant treatment after breast conservative surgery (N=154), or as a treatment of Hodgkin Lymphoma (N=9), underwent mastectomy (simple mastectomy, NAC-sparing and skin-sparing mastectomy) and implant-based, two-stage breast reconstruction. Inclusion criteria were: age between 25 and 75 years, absence of concomitant malignancies, grade 2 or 3 of Breast post Radiotherapy Reconstruction with ExpAnder Score Test (B.R.R.E.A.S.T. score) (Tab 1). Patient BMI, hypertension, smoking history, diabetes and having received neoadjuvant chemotherapy were not considered as exclusion criteria. Contextual mastectomy and expander positioning were performed during first stage (stage I), while substitution of the expander with definitive implant occurred during second stage (stage II). Fat grafting could be performed during stage I, between stage I and II surgery, or during stage II. Results. One hundred sixty-nine mastectomy procedures (six bilateral) and first-stage implant-based reconstructions with expander were performed either as prophylactic surgery (N=23) or for the treatment of primary or recurrent BC (N=146). Thirty-four patients had ductal carcinoma in situ, whereas 112 patients had invasive disease, including: 17 patients with Luminal A BC, 67 patients with Luminal B HER2-negative BC, 3 patients with Luminal B HER-2 positive BC, 7 patients with HER-2 positive BC and 18 patients had triple-negative BC. One hundred thirty-six (80.5%) patients received at least one fat grafting. Eighty-six patients (52.8%) have received second-stage definitive implant. With a median time of observation of 25.1 months, we observed four locoregional cancer recurrences (2.4%), one of which in axillary lymph nodes. All tumor recurrences occurred in patients who had received fat grafting. Eight patients (4.9%) developed distant metastases (liver, lung, lymph nodes, and bone metastases); of these, four patients (50%) had received fat grafting. No death events occurred. Conclusion. Fat grafting after radiotherapy of the breast is associated with a low incidence of locoregional tumor recurrences and distant metastases. Although our findings need to be confirmed in larger, multicentric clinical studies, fat grafting is a safe and useful technique that can be proposed for breast reconstruction after irradiation. Table. Breast post Radiotherapy Reconstruction with ExpAnder Score Test, B.R.R.E.A.S.T score. Based on our experience, we thought to include two tissue characteristics (Pinch test ≥ 0.5 cm and presence/absence of skin teleangectasia or severe dyscromia) in a pre-operative, clinically useful, and ready-to-use score to assess soft tissue adequacy as recommended by NCCN guidelines, that we called Breast post Radiotherapy Reconstruction with ExpAnder Score Test (B.R.R.E.A.S.T. score). In our study, two-stage implant-based breast reconstruction and adipose tissue transplant with regenerative intent were performed in patients with Pinch test ≥ 0.5 cm but moderate skin teleangectasia or dyscromia (B.R.R.E.A.S.T. score 2) and in patients with Pinch test ≥ 0.5 cm and absence of skin teleangectasia or severe dyscromia (B.R.R.E.A.S.T. score 3). Patients with skin teleangectasia or dyscromia and Pinch test 0.5 cm (B.R.R.E.A.S.T. score 1) were not enrolled in our study as they did not undergo alloplastic breast reconstruction but they underwent autologous reconstruction (data not shown). Citation Format: Chiara Listorti, Claudio Vernieri, Francesco Barretta, Chiara Osio, Ilaria Maugeri, Federica Pilotta, Cristina Ferraris, Massimiliano Gennaro, Gabriele Martelli, Marco Visaggio, Giulia Valeria Bianchi, Serena Di Cosimo, Gianfranco Scaperrotta, Maria Carmen De Santis, Daniela Tognali, Antonino Romeo, Matteo Mingozzi, Francesco Marongiu, Annalisa Curcio, Secondo Folli. Fat grafting is oncologically safe during implant-based breast reconstruction and mastectomy after radiotherapy for breast cancer or Hodgkin Lymphoma: results of a multicentric study abstract. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO4-27-11.
Listorti et al. (Thu,) studied this question.