Abstract
Keratinocyte cancer (KC) is the most prevalent cancer globally, with many patients developing multiple lesions as they age. Surgery is not practical for all patients, particularly older individuals with comorbidities such as vascular insufficiency or anticoagulation, which can be particularly challenging in anatomic locations such as the lower limbs. New radiotherapy (RT) technology and protocols have improved outcomes for patients by minimising toxicity whilst maintaining efficacy. An innovative RT protocol for KC treatment was developed to address this, definitive Adaptive Split Course Radiotherapy (ASCRT), in which the RT course is divided into two phases separated by an extended mid-treatment break with the aim of minimising toxicity. This study investigated the efficacy, safety, and patient satisfaction in a cohort of 47 patients from Queensland, Australia, who had 96 KC or symptomatic precancerous lesions on the lower limbs treated with a modified ASCRT protocol. Out of the complete cohort, 63 lesions that received both phases, the complete response rate was 98.4% (62/63), with only one grade 3 toxicity. Six patients developed an ulcer after treatment yielding an in-field ulcer rate of 6.6% (6/91), which resolved within 12-months. These results demonstrate that ASCRT is a viable treatment alternative for high-risk patient populations that potentially reduces toxicity without compromising efficacy. This protocol can potentially be expanded to other anatomic sites where there are concerns for the tolerability of a standard radiotherapy course.