Abstract P3-14-07: Neoadjuvant radiotherapy in mastectomy and immediate autologous free flap reconstruction. Findings from the primary radiotherapy and DIEP flap (PRADA) pilot study

Abstract

Abstract Background: The need for post mastectomy radiotherapy (PMRT), may preclude reconstructive surgeons from offering patients immediate, autologous reconstruction. This is due to historical evidence suggesting high rates of short- and long-term complications as well as poorer aesthetic outcomes. As the indications for PMRT broaden this practice denies an ever-increasing number of women the benefit of an immediate reconstruction. Aim: This pilot study evaluates the safety of offering radiotherapy prior to mastectomy and immediate DIEP flap reconstruction. Methods: Women planned for neoadjuvant chemotherapy (NAcT), mastectomy (following unsuccessful breast conservation surgery (BCS) or upfront selection) and PMRT were offered a change in sequencing of RT at two academic breast surgery units in London, UK. Data was prospectively captured on 19 women, including: patient demographics, treatment details, tumour characteristics, oncological and post-operative outcomes. Operative parameters included unplanned return to theatre [RTT] <30 days, mastectomy skin flap necrosis, and evidence of wound infection at 5 days, 4 and 12 weeks post-operatively. All mastectomies, were performed by one of 3 breast surgeons (DH, FAM, DRL) using a circumareolar incisions with one patient undergoing a vertical pattern incision for skin reduction. Results: The cohort demonstrated a broad range of age, body mass index (BMI) and mastectomy weight [mean (range): age=46 years (28-72); BMI = 28.4 kg/m2 (23-37.6) and specimen weight=678gm (257-1040)]. The mean time from completion of NAcT to neoadjuvant radiotherapy (NART) was 31.1 days (9-49 days), and time from completion of NART to mastectomy and DIEP was 17.8 days (13-24 days). There was one unplanned RTT at 72 hours for an evacuation of haematoma, 1 revision of micro-vascular anastomosis, 1 clinical fat necrosis requiring formal excision and 1 wound debridement and primary closure for poor wound healing (vertical pattern skin reduction). There were no flap failures and no mastectomy envelope necrosis. With a mean follow-up of 16.2 months, there were no loco-regional recurrences, 5 distant relapses with mean presentation at 13.7 months and 2 breast-cancer related deaths at 13.9 and 22.2months respectively. Conclusion: This pilot study suggests that mastectomy and DIEP reconstruction is surgically feasible within 4 weeks of completing NART. In this small cohort of oncologically high-risk women with altered sequencing of RT we did not observe flap failure or post-mastectomy skin flap necrosis. A larger multicentre study with aesthetic assessment, PROMS and translational aspects is planned. Citation Format: Thiruchelvam P, Hadjiminas D, Cleator S, Wood S, Leff D, Jallali N, James S, MacNeill F. Neoadjuvant radiotherapy in mastectomy and immediate autologous free flap reconstruction. Findings from the primary radiotherapy and DIEP flap (PRADA) pilot study [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P3-14-07.