2834 - Reconstruction Complications after Adjuvant Radiotherapy for Patients with Skin Cancer

Purpose/Objective(s): Reconstruction options for skin cancer after resection include skin graft (SG), free flap (FF), or local flap (LF). For patients who must undergo adjuvant radiation therapy (RT), breakdown of the reconstruction is a serious complication. The objective of this study was to compare reconstruction outcomes by type of reconstruction in patients receiving adjuvant RT.

Materials/Methods: A retrospective analysis of patients with cutaneous malignancies of the HN was performed, including all patients who underwent surgery & reconstruction followed by adjuvant RT at a single institution from 11/2008-6/2023. Primary outcomes analyzed included skin toxicity graded prospectively during RT & follow-up using CTCAE v5 scale & reconstruction failure defined as non-healing dehiscence. Statistical including chi square analysis was performed.

Results: 67 patients were identified as meeting inclusion criteria. Median follow-up was 33.5 months. The most common histology was squamous cell carcinoma (65.7%), followed by pleomorphic sarcoma (10.4%), melanoma (9.0%), basal cell carcinoma (6.0%). The most common primary tumor site was the scalp (44.8%). Table 1 summarizes treatment information across groups. The most common maximum dermatitis grade was Grade 2 for all groups: 45.0% (9/20) for SG, 72.4% (21/29) for FF, & 77.8% (14/18) for LF. Grade 3 dermatitis rates were 15.0% (3/20) for SG, 3.4% (1/29) for FF, & 0% (0/18) for LF. There was no statistically significant difference in the proportions of dermatitis grades (p=0.358). 3 patients (15.0%, 3/20) with SG developed ulceration, consisting of 1 Grade 2 partial thickness and 2 Grade 3 full thickness ulcerations. All 3 cases had primary site of vertex scalp & developed reconstruction failure with persistent bone exposure. In the FF and LF groups, 1 patient developed a Grade 2 partial thickness ulceration in each (3.4%, 1/29; 5.6%, 1/18), both recovering with wound care. Reconstruction failure free survival was significantly worse for patients with SG (p=0.018), with an estimated 1-year reconstruction failure rate of 10.0% for patients with SG compared to 0% for both FF and LF. Subgroup analysis of patients with primary tumors to of the vertex scalp revealed grade 3 dermatitis rates of 28.6% for patients with SG compared to 0% grade 3 dermatitis for patients with FF or LF.

Conclusion: Increased rates of grade 3 dermatitis (15.0% vs 3.4% vs 0%), ulceration (15.0% vs 3.4% vs 5.6%), & reconstruction failure were seen at 1 year (10.0% vs 0% vs 0%) in patients undergoing adjuvant RT after a SG compared to FF and LF. While reconstructive decision-making is complex & multifactorial, for patients who are likely to require postoperative RT, especially on the vertex scalp, there is lower risk of graft failure with FF or LF.