ESTRO 2021 Abstract Book

S244

ESTRO 2021

K. Joseph 1 , J. Wong 2 , A. Abraham 1 , A. Menon 3 , S. Ghosh 4 , H. Warkentin 5 , J. Walker 4 , T. Salopek 6 1 cross Cancer Institute, Radiation Oncology, Edmonton, Canada; 2 cross Cancer Institue, Radiation Oncology, Edmonton, Canada; 3 cross Cancer Institute, Radiation Oncology, Edmonton, Canada; 4 cross Cancer Institute, Medical Oncology, Edmonton, Canada; 5 cross Cancer Institute, Medical Physics, Edmonton, Canada; 6 university Of Alberta, Medicine, Edmonton, Canada Purpose or Objective Based on current evidence, wide local excision(WLE) with 1-3 cm clear margins and sentinel lymph node biopsy(SLNB) are the mainstay of treatment for non-metastatic MCC. RT is considered as the standard adjuvant treatment for MCC. Prospective data evaluating the role of adjuvant RT for MCC is unavailable. It is hypothesized that adjuvant RT improve outcomes of MCC patients. To better understand the efficacy of the adjuvant RT ,with or without regional nodal irradiation (RNI), with respect to outcomes, a population-based patterns of failure(POF) study was conducted to evaluate the potential indicators for adjuvant RT in the community setting. Considering most of the patients are elderly, we have also investigated the influence of comorbidity status on survival endpoints. Materials and Methods A chart review was performed following approval from the regional ethics board, and identified MCC patients treated in Alberta from 1988 to 2018. Results 217 patients (125 men, 92 women) were analyzed; the mean age was 79 (range: 33-96). The median follow up was 40 months. 100 patients received surgery alone and 117 patients had S+RT (55%) . The local recurrence(LR) was very low in low risk stage I (6, 6.5%) patients who had surgery with clear margin of ≥ 1cm and -ve SLNB, irrespective of adjuvant RT or not ,but not in stage II (8,21%) and stage III( 18,19%). Patients with T stage≥ 2 cm (HR: 2.947;p=0.024) and immunosuppression ( HR:3.988; p=0.001) were associated with high risk of nodal failure. Addition of RT independently associated with significant reduction in regional failure (HR: 0.36; p= 0.002). Incidence of distant metastases was very low in stage I(4/90) and stage II(4/34), in comparison to stage III(32/93). Adjuvant RT improved recurrence free survival(RFS ),not Merkel Cell Carcinoma Specific Survival (MCC-SS ) and overall survival(OS). Co-morbidity was a significant predictor of OS. In addition, OS worsened with age ≥ 65, immunosuppression. Conclusion Our study demonstrated that adjuvant RT improved loco-regional control and RFS, without impact on MCC-SS and OS. Co-morbidity rather than adjuvant RT influenced overall survival. Based on our results, we suggest adjuvant local RT may be avoided in stage I low-risk patients with negative SLNB with adequate margin clearance. Adjuvant RT is recommended for patients with associated high risk factors such as positive or close margin, immunosuppression and LVI. Prophylactic RNI should be offered in stage II patients with negative SLNB , with associated immunosuppression . All stage III patients were benefited with adjuvant RNI, but with little effect to prevent distant metastases. Given the high risk of distant relapse among stage III patients, and RT has little effect to prevent distant metastases, future prospective multicentric evaluations of systemic management with chemotherapy /immunotherapy along with adjuvant RT is recommended for stage III patients. PH-0332 The role of multidimensional evaluation in curative radiotherapy for elderly patients (aged ≥75) L. Gasparini 1,2 , L. Caravatta 1 , M. Taraborrelli 1 , F. Allega 1 , M. Candeloro 3 , I. Bottone 4 , E. Porreca 3 , D. Genovesi 2,1 1 SS. Annunziata Hospital, Department of Radiation Oncology, Chieti, Italy; 2 G. D'Annunzio University, Department of Neuroscience, Imaging and Clinical Sciences, Chieti, Italy; 3 G. D'Annunzio University, Department of Innovative Technologies in Medicine and Dentistry, Chieti, Italy; 4 SS. Annunziata Hospital, General Medicine 2 Unit, Chieti, Italy Purpose or Objective The concept of frailty is a complex, multidimensional and cyclical state of vulnerability that has recognized as one of the most important issues in health care that can affect treatment approach and clinical outcomes. Despite the high cancer prevalence in elderly people, the optimal treatment for elderly patients remains challenging, due to the incidence of age–related pathologies that could affect patient’s functional capabilities. In this contest, the aim of the study was the identification of frail patients, candidate for curative radiotherapy (RT) and to measure through multidisciplinary and multidimensional approach the impact of frailty on toxicities and outcomes. Materials and Methods A prospective observational study was designed in our Center for all patients with >75years, candidate for curative RT. Frail patients were identified by the radiation oncologist, before and at the end of RT, by Geriatric8 questionnaire (G8q). All frail patients (score <14) were then evaluated by a multidimensional geriatric assessment, investigating cognitive (MMSE, GDS), functional (ADL, IADL, Tinetti) and nutritional (MNA short) domains, to define the frailty phenotype. The geriatric assessment was repeated at 6 and 12 months after RT (Figure 1).