Introduction: Non-melanoma skin cancers represent the most common cancers in humans, ac- counting for 80% of all skin cancer cases. The majority of these cancers are localized in areas that are most exposed to the sun, particularly the scalp, face, and back of the hand.
The treatment of choice in most cases is surgery, specifically Mohs micrographic surgery, which is considered the best option for non-melanoma skin cancer, with a cure rate of over 95% after 5 years. However, the main limitation of this practice is in patients with large or multiple lesions located in areas where radical surgical approach is technically challenging or disfiguring, such as the ears, eye- lids, lips, external genitals, or fingers. In these cases, surgical results may be suboptimal. High-dose brachytherapy with unsealed rhenium-188 resin is a recent therapeutic option for the treatment of non-melanoma skin cancers. This technique has been shown to be safe, well-tolerated, and practical for lesions on the face, nose, scalp, extremities, and lesions that are difficult to access with surgery and radiotherapy. It is also being used for the first time in Switzerland at CHUV, Lausanne. In this context, it is interesting to report the experience and initial oncological and cosmetic results of this technique during its introduction at CHUV.
Objectives: To provide a description of the experience of introducing this new technique at CHUV, as well as the initial oncological and cosmetic results, any side effects, and its place among the avail- able techniques (surgery, radiotherapy) for patients with non-melanoma skin tumors.
Methods: Inclusion criteria were: (1) histologically proven basal cell carcinoma or squamous cell carcinoma; maximum thickness of 2.5 mm after shaving, if necessary (limit of Re-188 treatment); (2) lesion(s) localized on the scalp, face, ears, fingers, or other areas where surgery or external radiotherapy would be difficult to perform, contraindicated, or refused by the patient.
Exclusion criteria were: (1) patient refusal of Re-188 therapy or (2) inability to cooperate during the application of radioactive resin that would render radiation protection impossible.
Evaluation of side effects were conducted using the CTCAE (Common Terminology Criteria for Adverse Events) scale, and evaluation of cosmetic results at 12 months using the RTOG (Radiation Therapy Oncology Group) scale. Patients were followed up in the dermatology clinic at 14, 30, 60, 90, and 180 days, and then annually. Evaluation of the need for re-treatment with Re-188 or additional surgical excision were also performed.
Results: At the end of the study, for the CTCAE scale we had 7/16 lesions (44%) with G1 toxicity, 5/16 lesions (31%) with a G3 toxicity, and the toxicity of 4 lesions was not documented. These toxic effects occurred approximately at day 14 and lasted for 2-3 months. For the RTOG scale, all our patients were very satisfied with the results, with 15/16 cosmetic results considered excellent, and only one considered good. Only one relapse was documented 16 months after the treatment, with a total of 15/16 (94%) lesions that completely responded to the therapy.
Discussion: Despite our relatively small observation group, the data we gathered was very encour- aging, showing the potential of the introduction of this new technique as an alternative treatment for non-melanoma skin cancers, which, for this short study, demonstrated to be safe, well-tolerated, and practical for lesions that are difficult to access with surgery and radiotherapy. To complete this study, larger groups should be analysed for a longer follow up, to confirm this encouraging preliminary data.