Lesion-based radiotherapy for non-melanoma skin cancer of the lower legs with a focus on radiation induced ulcers

Abstract

Aim:Non-melanoma skin cancer (NMSC) of the lower legs is a challenge to treat. Surgery can be difficult given the challenged blood supply.Radiotherapy (RT) is a controversial treatment modality and some radiation oncologists (ROs) will not offer definitive treatment for lesions below the knee for fear of creating a radiation-induced ulcer. This study is a retrospective audit of a single RO’s treatment of lower leg NMSCs. The aim is to evaluate the efficacy of RT in gaining local control of these lesions. The aim is also to document the development of late side effects following RT, including radiation-induced ulcers and their treatment. Referral growth over time was also investigated. Methods:Electronic medical records were searched for patients with lower leg NMSCs treated by the RO between January 2009 and December 2019 at three locations in Sydney, Australia (St Vincent’s Hospital, Mater Hospital, and Macquarie University Hospital). Patient, tumour, treatment, and outcome factors were collected and analysed.Referrals over time were recorded. Results:111 lesions arising in 56 patients were identified. There was even distribution of sex and the mean age was 82 (range 57–95). There were 78 cutaneous squamous cell carcinomas (cSCCs) and 23 basal cell carcinomas (BCC). Median lesion size was 2 centimetres (range 1–10cm). The most common RT modality used was electrons (91 [82%]), followed by superficial RT (SXRT) (20 [18%]). Median duration of follow-up was 4 months (range 0–117 months). Of the 77 lesions treated with curative intent, cure was achieved in 74 (96%) lesions. 2 cSCCs and 1 BCC recurred, with a median time to recurrence of 24 months. 15 (14%) lesions developed a radiation-induced ulcer following RT. Median duration of therapy required for these ulcers was 5 months (range 1–55 months), with conservative treatment being the most common therapy used. Referrals increased from 8 in the 2008-2011 period to 26 in the 2016-2019 period. Conclusion: This study showed RT treatment of lower leg NMSCs achieves local control of lesions with an acceptably low rate of radiation-induced ulcers, thus supporting the use of this modality for this patient population. Referrals grew over time which may reflect growing referrer knowledge and confidence in definitive RT below the knee.