ESTRO 37 Abstract book

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ESTRO 37

Management was lymphadenectomy alone in 21 (27%) patients, lymphadenectomy and adjuvant radiotherapy in 54 (69.2%), lymphadenectomy and adjuvant chemo- radiotherapy 1 (1.3%) and neo-adjuvant radiotherapy followed by lymphadenectomy 2 (2.6%). 5 year OS was 33% (95% CI: 23-47%) in this population (figure). 31 (39.7%) recurred within the treated regional lymph nodes and 21 (26.9%) developed distant metastasis. On univariate analysis, significant factors for improved survival were younger age (p=0.016), better performance status (p=0.03), lack of immunosuppression (p=0.001), a lower lymphocyte ratio (p=0.015) and the use of radiotherapy (p=0.009).

Figure 2. Radiation effect on secretions of cytokines using ELISA. Conclusion In our study, we demonstrated that radiation alters the immune profile of RCC cell lines by altering PD-L1 levels, cytokine secretion and immune-related gene expression. Taken together, the strategy of combining radiotherapy and immunotherapy has the potential to improve the response rates of immunotherapy for patients with RCC.

Electronic Poster: Clinical track: Skin cancer / malignant melanoma

EP-1623 Overall survival of patients with cutaneous SCC metastasis to the axilla or groin N. Bucknell 1 , M. Bressel 2 , A. Webb 3 , D. Gyorki 3 , M. Henderson 3 , V. Estall 1 , A. Tiong 1 1 Peter MacCallum Cancer Center, Radiation Oncology, Melbourne, Australia 2 Peter MacCallum Cancer Center, Biostatistics and Clinical Trials Unit, Melbourne, Australia 3 Peter MacCallum Cancer Center, Surgical Oncology, Melbourne, Australia Purpose or Objective Metastasis of cutaneous squamous cell carcinoma (cSCC) to regional lymph nodes of the upper and lower limb are uncommon events. They are described in regions where there is high ultraviolet light exposure with populations of low Fitzpatrick score skin types. These cancers are generally treated with lymphadenectomy and adjuvant (chemo)radiotherapy for those with high risk features (tumours larger than 3cm, involvement of three or more nodes or extra-nodal extension). Unfortunately there is scant published data in this area to guide management: the largest retrospective series has 26 patients. We therefore examined a larger series of patients treated at our institution for their overall survival and prognostic factors. Material and Methods We performed a retrospective chart review of patients treated at our institution from January 2000 to July 2015. Included patients had histologically confirmed cSCC metastatic to either axilla or inguinal nodes, 18 years or older, did not have non-cutaneous primary identified and were treated with lymphadenectomy with/without adjuvant treatment. Overall survival (OS) was described using Kaplan-Meier methods and prognostic factors for OS were analysed with univariate Cox models. Results 78 patients met the inclusion criteria. The mean age was 73 years (29-95), 54 (67.9%) were male, 56 (72%) were ECOG 0 or 1 and 8 (10.5%) were immunosuppressed. Staging was performed with CT scan in 75 (96%) and PET in 39 (50%). 64 (82%) patients had axillary involvement while 14 (18%) involved the inguinal region. The average number of nodes involved was 3.7 (range: 1-22) and the mean size of the largest node was 47.9mm (range: 8-135). 63 (80.8%) had extra-nodal extension.

Figure 1 - Kaplan-Meier overall survival curve for the 78 patients

Conclusion In this uncommon scenario, the survival is poor. Contributory factors may be older age with associated comorbidities. However, relapse within the treated regional lymph node and distant metastasis were also frequent. Multivariate analysis will be needed to examine the impact of possible prognostic factors to guide future studies aimed at improving prognosis for these patients: this may include identifying an optimal radiation dose and identifying patients at high risk of distant metastasis for clinical systemic trials. EP-1624 Forty large convex fields of skin cancer treated with volumetric arc therapy in Australia. G. Fogarty 1 , N. Molloy 1 , M. Fay 2 , A. Kaminski 3 , D. Schlect 3 , D. Christie 4 , L. Spelman 5 , R. Sinclair 5 1 Genesis Cancer Care- St Vincent's Hospital- Sydney, Radiation Oncology, Crows Nest, Australia 2 Genesis Cancer Care- Lake Macquarie Private Hospital- Newcastle, Radiation Oncology, Newcastle, Australia 3 Genesis Cancer Care- Wesley Hospital- Brisbane, Radiation Oncology, Brisbane, Australia 4 Genesis Cancer Care- Nambour Hospital- Gold Coast, Radiation Oncology, Gold Coast, Australia 5 Gabba Dermatology, Dermatology, Brisbane, Australia Purpose or Objective Australia has the highest incidence of skin cancer in the world. Some patients suffer with large fields of Bowen's disease from which new invasive cutaneous squamous cell carcinoma (cSCC) can arise, the rate accelerating with age, particularly in the immunosuppressed. These patients can have poor oncological outcomes, but also poor quality of life, with itch, flaking skin and poor cosmesis. They can have comorbidities that can preclude other treatments. The durability of tradition field treatments is disappointing. New radiation techniques