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Aim: To describe the feasibility of image guided intensity modulated radiotherapy (IG-IMRT) using daily soft tissue matching in the treatment of bladder cancer. Methods: Twenty-eight patients with muscle-invasive carcinoma of the bladder were recruited to a protocol of definitive radiation using IMRT with accelerated hypofractionation with simultaneous integrated boost (SIB). Isotropic margins of.5 and 1cm were used to generate the high risk and intermediate risk planning target volumes respectively. Cone beam CT (CBCT) was acquired daily and a soft tissue match was performed. Cystoscopy was scheduled 6weeks post treatment. Results: The median age was 83years (range 58-92). Twenty patients had stage II or III disease, and eight were stage IV. Gross disease received 66Gy in 30 fractions in 11 patients (ten with concurrent chemotherapy) or 55Gy in 20 fractions for those of poorer performance status or with palliative intent. All patients completed radiation treatment as planned. Three patients ceased chemotherapy early due to toxicity. Six patients (21%) had acute Grade≥2 genitourinary (GU) toxicity and six (21%) had acute Grade≥2 gastrointestinal (GI) toxicity. Five patients (18%) developed Grade ≥2 late GU toxicity and no ≥2 late GI toxicity was observed. Nineteen patients underwent cystoscopy following radiation, with complete response (CR) in 16 cases (86%), including all patients treated with chemoradiotherapy. Eight patients relapsed, four of which were local relapses. Of the patients with local recurrence, one underwent salvage cystectomy. For patients treated with definitive intent, freedom from locoregional recurrence (FFLR) and overall survival (OS) was 90%/100% for chemoradiotherapy versus 86%/69% for radiotherapy alone. Conclusion: IG- IMRT using daily soft tissue matching is a feasible in the treatment of bladder cancer, enabling the delivery of accelerated synchronous integrated boost with good early local control outcomes and low toxicity.
Whalley, D., Caine, H., McCloud, P., Guo, L., Kneebone, A., & Eade, T. (2015). Promising results with image guided intensity modulated radiotherapy for muscle invasive bladder cancer. Radiation Oncology, 10(1). https://doi.org/10.1186/s13014-015-0499-0