Electron beam radiotherapy in giant non- melanoma skin cancers of the head in elderly inoperable patients: a single centre retrospective study

Background: Electron beam three-dimensional conformal radiotherapy (3D-CRT) may be an alternative effective option for the treatment of giant nonmelanoma skin cancers (NMSCs) of the head in older patients unfit for surgery. Here, we present a retrospective study of older patients with giant NMSCs of the head treated with 3D-conformal electron beam radiotherapy, including analysis of clinical outcomes and factors impacting local control. Materials and methods: Fifty older patients with sixty T3–T4 giant and aggressive NMSC lesions of the head, irradiated between 2005 and 2015, were retrospectively studied. Treatment consisted of one or two fields of customized electron beams planned using 3D conformal radiotherapy. Univariate analysis with Chi-square, Cox proportional hazard ratio, and Pearson’s covariance for multivariate analyses, assuming P<0.05 for statistical significance, were used to assess the impact of clinical and dosimetric parameters on local control. Results: Complete response (CR) occurred in 15 patients and 25 lesions. Bleeding control was obtained for all symptomatic lesions. Cumulative local progression free survival rates at 2 and 5 years were 85% and 78%, respectively. On univariate analysis several factors were found to significantly impact local progression, including diabetes (P<0.001) and primary site (P<0.03), with scalp being significant for durable local control (P<0.02). On multivariate analysis, both factors were confirmed as significant prognostic indicators of local control. Treatment was well-tolerated with acceptable acute and late toxicity and good palliation effect. Conclusion: Customized electron beam 3D CRT for giant NMSCs of the head not amendable to surgery in frail older patients can be considered an effective and safe option in both curative and palliative settings.