2925 - Salvage Preoperative Radiotherapy and Surgery for Recurrent Breast Cancer
Presenter(s)
M. Chao1,2, C. Yong3, E. Bevington4, J. Lippey5, J. Chionh6, J. Dean2, M. Tacey2, T. Jenkins2, A. Qadir2, B. Farrugia2, and F. Foroudi2; 1Genesis Care, Ringwood, Melbourne, VIC, Australia, 2Olivia Newton John Cancer Wellness and Research Centre, Austin Hospital, Melbourne, VIC, Australia, 3Maroondah Hospital, Melbourne, VIC, Australia, 4Austin Health, Melbourne, VIC, Australia, 5St Vincent's Hospital, Melbourne, VIC, Australia, 6The Austin Hospital, Melbourne, VIC, Australia
Purpose/Objective(s): Mastectomy has long been considered the treatment of choice for ipsilateral breast recurrence following wide local excision (WLE) and radiotherapy (RT), primarily due to concerns regarding cosmetic outcomes and the potential complications associated with additional surgery or radiation. Local failure rates after mastectomy range from 3-32%, while repeat WLE alone results in local recurrence rates of 20-35%. Recent studies have explored the combination of repeat WLE with partial breast irradiation (PBI) to reduce recurrence risk. Notably, the NRG study demonstrated that salvage WLE combined with PBI (45Gy in 30 fractions) over 3 weeks yielded low recurrence rates, acceptable toxicity, and favorable cosmetic results. This prospective feasibility study investigates the use of salvage preoperative PBI, guided by magnetic resonance imaging (MRI), in combination with WLE for recurrent ipsilateral breast cancer. Here, we present the outcomes of the first five patients in this study.
Materials/Methods: Patients included in the study were over 50 years of age, with recurrent, clinically node-negative, estrogen receptor-positive (ER+), unifocal breast cancers smaller than 3 cm on pre-treatment imaging. To be eligible, patients had to have a minimum of one year since prior radiation therapy. The tumor or gross tumor volume (GTV) was identified using MRI and expanded by 15mm to define the clinical target volume (CTV). The planning target volume (PTV) was created by further expanding the CTV by 5mm. The GTV was treated to a dose of 30Gy in 5 fractions, with the PTV receiving a minimum dose of 26Gy delivered on our Unity MRI Linac.
Results: The median age was 73 years, and the mean MRI GTV size was 11mm (range 5-15mm). The median time since prior radiation therapy was 17 years, with previous RT doses ranging from 45-50Gy. All patients received 26Gy in 5 fractions of preoperative PBI, followed by salvage WLE 6 weeks later. Final pathology revealed 1 pathological complete response, while the remaining tumors ranged in size from 4mm to 28mm. Of the four patients with residual disease, all were ER+, with two tumors classified as grade 1 and two as grade 2. One patient had a positive margin, which was addressed with re-excision, resulting in clear margins and no residual disease. The minimum follow-up time post-surgery was 6 months. One patient experienced a Clavien-Dindo (CD) grade 3 complication, developing wound dehiscence approximately 6 weeks after surgery. This complication required further surgical intervention with a wider excision and flap reconstruction. Additionally, one patient experienced a CD grade 2 complication, developing a postoperative infection following her re-excision.
Conclusion: This study provides preliminary evidence of the feasibility and safety of this novel treatment strategy. Although complications were minimal, the occurrence of one significant wound complication underscores the need for further refinement.