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BACKGROUND: Anal cancer is a rare cancer with rising incidence. Despite the relatively good outcomes conferred by state-of-the-art chemoradiotherapy, further improving disease control and reducing toxicity has proven challenging. Developing and validating prognostic models using routinely collected data may provide new insights for treatment development and selection. However, due to the rarity of the cancer, it can be difficult to obtain sufficient data, especially from single centres, to develop and validate robust models. Moreover, multi-centre model development is hampered by ethical barriers and data protection regulations that often limit accessibility to patient data. Distributed (or federated) learning allows models to be developed using data from multiple centres without any individual-level patient data leaving the originating centre, therefore preserving patient data privacy. This work builds on the proof-of-concept three-centre atomCAT1 study and describes the protocol for the multi-centre atomCAT2 study, which aims to develop and validate robust prognostic models for three clinically important outcomes in anal cancer following chemoradiotherapy. METHODS: This is a retrospective multi-centre cohort study, investigating overall survival, locoregional control and freedom from distant metastasis after primary chemoradiotherapy for anal squamous cell carcinoma. Patient data will be extracted and organised at each participating radiotherapy centre (n = 18). Candidate prognostic factors have been identified through literature review and expert opinion. Summary statistics will be calculated and exchanged between centres prior to modelling. The primary analysis will involve developing and validating Cox proportional hazards models across centres for each outcome through distributed learning. Outcomes at specific timepoints of interest and factor effect estimates will be reported, allowing for outcome prediction for future patients. DISCUSSION: The atomCAT2 study will analyse one of the largest available cross-institutional cohorts of patients with anal cancer treated with chemoradiotherapy. The analysis aims to provide information on current international clinical practice outcomes and may aid the personalisation and design of future anal cancer clinical trials through contributing to a better understanding of patient risk stratification.
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PURPOSE: The aim of this study was to present a case of complete clinical response of renal clear cell carcinoma cutaneous metastases after high-dose-rate surface brachytherapy (HDR sBT). MATERIAL AND METHODS: An 81-year-old female diagnosed with stage IV clear cell renal carcinoma reported to our center with painful relapse of two cutaneous metastases after a previous metastasectomy. The patient was disqualified from systemic therapy due to comorbidities, and qualified to attempt a treatment using HDR sBT. The unit equipped with an iridium-192 source was used to deliver 36 Gy/6 Gy in 6 fractions twice weekly. Overall treatment time was 18 days. RESULTS: Two weeks after HDR sBT, complete response was observed in one irradiated location, while the partial response was observed in the latter. EORTC grade 1 skin toxicity was reported in both irradiated fields. Three and five months after the treatment, the patient presented complete response and pain relief in both locations with no signs of relapse. The patient remained in palliative care and died seven months after the treatment due to sudden cardiac death. CONCLUSIONS: HDR sBT can be a valuable treatment option for cutaneous metastatic renal cell carcinoma, especially for patients with significant comorbidities. The treatment provided was associated with low toxicity and excellent clinical outcome.