Treatment of Basal Cell Carcinoma of the Lower Eyelid With High-Dose-Rate Brachytherapy.

Objective To report the outcomes with high-dose-rate (HDR) brachytherapy (BT) treatment in patients with lower eyelid basal cell carcinoma (BCC) and to evaluate the relationship between dosimetric parameters and acute and late toxicities. Material and methods A retrospective unicentric study with patients diagnosed with lower eyelid biopsy-proven BCC treated with HDR BT between January 2012 and December 2019. The prescribed dose was 36 Gy to 40 Gy in 9 to 10 fractions, twice daily, over five days. The primary endpoint was local control, and the secondary endpoints were acute and late toxicities, registered according to CTCAE v4.0. The cosmetic result was evaluated on a qualitative scale (the CAIB scale). Local control was calculated according to the Kaplan-Meier test. Two sample T-tests and a Wilcoxon signed-rank test were used to determine the association between dosimetric parameters and side effects. Results Fifty-eight patients with a median age of 76 years were included. Among these patients, 55.2% received adjuvant HDR BT and 44.8% received radical HDR BT. At a median follow-up of 44 months, there were four local relapses, achieving a probability of local control at four years of 95% and 100% in the adjuvant and radical groups, respectively. Acute toxicity occurred in 76% of patients with only one grade 3 event (radiation dermatitis). Late toxicity was present in 56%. Eight patients underwent treatment for grade 3 cataracts during follow-up. Cosmetic results were excellent or very good in 93% of patients. Acute conjunctival hyperemia is strongly associated with the dose received by the ocular globe (volumes of 0.1cc, 1cc, and 2 cc) (p<0.05). Conclusion Lower eyelid BCC treatment with interstitial HDR BT is associated with excellent local control, acceptable long-term side effects, and good cosmetic results.