P106. Chest Wall Perforator Flaps in Breast-Conserving Surgery: an Effective and Safe Tool to Reduce Mastectomy Rates. Updated results from the SCARABEO (SCARless Advanced Breast Extended Oncoplasty) International Multicentric Study

Breast-conserving surgery (BCS) with chest wall perforator flap (CWPF) based partial breast reconstruction (PBR) enables wide oncologic excisions while preserving excellent aesthetic outcomes, even in challenging clinical scenarios. The SCARABEO project aims to evaluate the surgical and oncological outcomes of these procedures in a large international cohort.



Methods:

This retrospective multicentric international study included patients who underwent BCS with CWPF based PBR for stage 0-III breast cancer. Patients were treated between 2014-2024 in 9 Breast Units located in Italy, Brazil, USA, India, Singapore, and UK. 


Results:

A total of 641 women (median age 57 years) were included. All procedures were performed by general surgeons. Median tumor diameter was 26 mm (IQR 18-32) and 28.2% of the cases were multifocal. The majority of patients would have traditionally been candidates for mastectomy. PBRs were performed using LICAP (52%), AICAP (16%), MICAP (11%), LTAP (15%), TDAP (2%), and combined flaps (4%). Symmetrization surgery was required in 2.2% of cases. Median operative time was 125 minutes (IQR 105–155) and 47.9% were Day Surgery cases. Pedicle mapping with Power Color Doppler was performed in 27% of cases Median flap volume was 87.5 cm³ (IQR 60–120) and specimen volume was 81.4 cm³ (IQR 63.7–110.1), accounting for 26.3% of breast volume (IQR 18.9–36.4) with a specimen-to-ORV ratio of 1.10 (IQR 0.9–1.5). Overall positive margin rate was 14.6%, leading to re-excisions  in 83.1% and completion mastectomy in 10.1% of the cases. Adjuvant radiotherapy was administered in 94.4% of patients, with no flap-related late effects observed. The overall complication rate was 21.9%, with seroma being the most common (10.4%) and flap loss occurring in 2 cases (0.3%); 83.7% were managed in an outpatient setting. Age, BMI, smoking habit, neoadjuvant chemotherapy, CWPFs type, CWPFs’ and specimens’ volume were associated with a higher risk of post-operative complications. At a median follow-up of 37 months (IQR 15-54), local recurrence occurred in 2.3% of patients, distant recurrence in 2.6% and breast cancer–related death in 1.1%.



Conclusions:

In this largest series to date, BCS with CWPF based PBR achieved excellent surgical outcomes and favorable short-term oncologic results, effectively expanding the boundaries of BCS in patients with high tumor-to-breast volume ratios. Longer follow-up and prospective validation are warranted to confirm these promising results.