175 - Surgical Graft and Flap Toxicity Following Hypofractionated Adjuvant Radiotherapy for Primary Cutaneous Melanoma
Presenter(s)
N. X. Yang1,2, A. J. Arifin3, A. F. M. Salem Jr1, A. K. Yoder4, S. Keatts1, O. Jerez1, R. Lin1, A. J. Bishop4, A. Farooqi4, R. P. Goepfert1, R. Weiser1, M. I. Ross1, B. A. Guadagnolo4, A. Mericli1, and D. Mitra4; 1The University of Texas MD Anderson Cancer Center, Houston, TX, 2McGovern Medical School at UTHealth Houston, Houston, TX, 3London Health Sciences Centre, Western University, London, ON, Canada, 4Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX
Purpose/Objective(s): Adjuvant radiotherapy (RT) decreases the likelihood of local recurrence after resection of high-risk cutaneous melanoma. However, RT may be detrimental to the healing of graft or flap reconstructions often needed for wound closure. The likelihood of adjuvant RT causing wound healing complications resulting in surgical revision is unknown. This study aims to determine the rate of surgical graft or flap revision after hypofractionated adjuvant RT for melanoma.
Materials/Methods: We identified 193 cutaneous melanoma patients who received 30 Gy in 5 fraction adjuvant primary site RT (prescribed to Dmax, 2-3 days/week) with a graft or flap reconstruction between 2008-2021. Clinical characteristics, including surgical complications, were collected. Chi-square testing evaluated predictors of surgical revision.
Results: The median age of the patient cohort was 68 years (IQR 60-77) with 80% being male (n=155). Most had at least one comorbidity known to be associated with compromised wound healing: 70% (n=136) had cardiovascular disease, 64% (n=124) were overweight, and 23% (n=44) had type 2 diabetes.
The most common anatomic site was the head and neck (H&N, 89%, n=171). Subsites included scalp (n=97, 57%), cheek (n=24, 14%), and forehead/temple (n=18, 11%). Indications for RT included perineural invasion (n=108, 56%), microsatellites (n=49, 25%), Breslow thickness (median 5 mm, IQR 2.9-7.5), ulceration (n=65, 34%), and desmoplastic histology (n=5, 3%) with 91 (47%) patients having more than one of these risk factors. 67% of patients (n=129) underwent reconstruction with a graft (36% full thickness, n=47; 51% partial thickness, n=66) and 33% (n=64) had a flap alone. A median of 7 weeks (IQR 5-9) elapsed between resection and RT. The most common RT modality was electrons (n=166, 86%). Median follow-up from reconstruction was 46 months (IQR 23-82). Nine patients (4.6%) required surgical revision. Four revisions (2 flap and 2 graft) occurred before RT and 5 revisions (2.6%) occurred after RT. All post-RT revisions occurred after graft reconstructions (3.9% of grafts) in male patients, with a median age of 71 (IQR 64-73). Four post-RT revisions were in the H&N and 1 was in the lower extremity. Comorbidities in the post-RT revision patients included BMI>25 (n=4), diabetes (n=3), and cardiovascular disease (n=3). The median time from surgery to RT among the 5 patients requiring revision after RT was 7 weeks (IQR 5-8). In the context of a low event rate, there were no statistically significant associations between baseline factors and risk of requiring a surgical revision.Conclusion: This study demonstrates that the risk of surgical revision after hypofractionated adjuvant RT to a graft or flap reconstruction is low with no flap failures and <4% graft failures. These results support the continued use of hypofractionated RT as a well-tolerated option in the postoperative setting.