ESTRO 2020 Abstract book

S692 ESTRO 2020

Conclusion ICB is less effective in Korean patients with advanced melanoma compared to their Western counterparts due to modest response rates in non-CSD types, which account for 97% of malignant melanoma in Korea population. The present data provides a strong rationale for initiating combination immunotherapy approaches, and contributes to launch phase II study to investigate whether RT plus immunotherapy increase the level of antimelanoma activity (NCT04017897). PO-1225 Skin radiotherapy training programme for dermatology specialty trainees - an unmet need A. Rembielak 1 , T. Ahad 2 , A. Sanneh 3 1 The Christie Hospital and The University of Manchester, Clinical Oncology, Manchester, United Kingdom ; 2 Salford Royal NHS Foundation Trust, Dermatology, Salford, United Kingdom ; 3 The Christie Hospital, Radiotherapy, Manchester, United Kingdom Purpose or Objective Radiotherapy is an important modality for the treatment of skin malignancies. Although an integral part of the dermatology curriculum, exposure and knowledge in skin radiotherapy is limited amongst dermatology specialty trainees. The dermatology UK national curriculum specifies competency in the principles, indications, risks and benefits of radiotherapy and ability to construct a treatment plan for primary skin malignancy. Trainees are currently independently responsible for arranging means of fulfilling this requirement, which may be through independent study, observerships or courses as agreed with their educational supervisor. Quality of training in this field can therefore be varied and often becomes a box- ticking exercise. This can in turn affect quality of referrals made to radiotherapy clinics and limit treatment choices offered to patients. Material and Methods To address this gap in training, an innovative programme to deliver radiotherapy training in skin malignancies was designed for the UK North-Western Dermatology Deanery. The training programme consisted of a radiotherapy training day at the Christie Hospital, Manchester and participation in at least two skin radiotherapy clinics. The radiotherapy training day consisted of interactive lectures covering curriculum objectives, followed by small group practical sessions exploring radiotherapy equipment, procedures and patients’ experience. This was delivered by a multi-disciplinary team involving radiotherapy doctors, radiographers and medical physicists. The clinics included new and follow-up patients with skin cancer, skin marking planning sessions and on-treatment reviews. Results Feedback was obtained through anonymised survey responses (observership in clinics) and feedback forms (study day). Responders rated their knowledge in radiotherapy as ‘below average’ prior to the programme and as feeling ‘confident’ after the programme. Learning objectives fulfilled by the teaching programme according to the responders included indications and contraindications for skin radiotherapy, optimal patients to refer for radiotherapy, methods of delivering radiotherapy, patient compliance, management of skin toxicities, radiotherapy planning and shielding, geriatric assessment, dealing with patients who lack capacity and patients’ involvement in the decision making process. Conclusion Overall, feedback received indicated that this programme succeeded in sufficiently increasing knowledge and confidence amongst dermatology specialty trainees in skin radiotherapy. Subsequent incorporation of this programme into dermatology training and addition of regular radiotherapy clinics into the dermatology registrar rota have now streamlined training dermatology trainees receive in this field, ensuring that curriculum objectives

Conclusion SRT is a good treatment for epithelial skin cancer with an excellent local control. There is a high risk of recurrence in SCC and T3 stage in our patients. PO-1224 Clinical outcomes of malignant melanoma treated with immune checkpoint blocker in Korean patients J. Lee 1 , J.S. Chang 2 , M.R. Roh 3 , B.H. Oh 3 , K.Y. Chung 3 , W.S. Koom 4 , S.J. Shin 5 1 Inha University Hospital, Radiation Oncology, Incheon, Korea Republic of ; 2 Yonsei University College of Medicine, Radiation Oncology-, Seoul, Korea Republic of ; 3 Yonsei University College of Medicine, Dermatology, Seoul, Korea Republic of ; 4 Yonsei University College of Medicine, Radiation Oncology, Seoul, Korea Republic of ; 5 Yonsei University College of Medicine, Medical Oncology, Seoul, Korea Republic of Purpose or Objective Early clinical trials established the efficacy of immune checkpoint blocker (ICB) in advanced malignant melanoma. Because there is considerable discrepancy in clinical subtypes of melanoma between different races and populations, its efficacy remains to be elucidated in Asian populations. Material and Methods We retrospectively reviewed 127 patients with metastatic or advanced melanoma treated with ICB between 2014 to 2018. Clinical subtypes of melanoma were classified by extent of solar elastosis around tumor and anatomical site, as follows: chronically sun-damaged (CSD) and non-CSD melanomas (acral lentiginous, mucosal and uveal types). Primary endpoint was objective response rates (ORR) included complete and partial response rate. We attempted to seek links between a close temporal relationship of palliative RT and ICB and increased ORR. Results The iRECIST ORR was 15% (95% CI 9.3-22.4), with 11 complete and 8 partial responses. The ORR was 50% for CSD type, 16.5% for acral or mucosal type, and 0% for uveal type ( P = .009). Aside from clinical subtypes, stage at treatment (M1a/unresectable vs. M1b/c/d; 36.1% vs. 6.6%), total tumor burden based on the sum of the longest diameters of target lesions (< 4 mL vs. ≥ 4 mL; 37.1% vs. 6.5%), and types of ICB (anti-PD-1 vs. anti-CTLA-4; 18.8% vs. 3.2%) were significantly associated with ORR. Administration of palliative RT seems likely to increase the ORR, only when there is close temporal relation between ICB and RT (< 2 weeks vs. ≥ 2 weeks, 22.2% vs. 11%, P =.089). Clinical responders to ICB had significantly improved progression-free and overall survivals than non- responders (61.2% vs 8.7% at 1-year, P < .001 and 100% vs 71.2% at 1-year, P = .015, respectively).