Promising results with image guided intensity modulated radiotherapy for muscle invasive bladder cancer

Abstract

AimTo describe the feasibility of image guided intensity modulated radiotherapy (IG-IMRT) using daily soft tissue matching in the treatment of bladder cancer.MethodsTwenty-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 1 cm 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 6 weeks post treatment.ResultsThe median age was 83 years (range 58-92). Twenty patients had stage II or III disease, and eight were stage IV. Gross disease received 66 Gy in 30 fractions in 11 patients (ten with concurrent chemotherapy) or 55 Gy 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.ConclusionIG- 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.

EAU-ESMO Consensus Statements on the Management of Advanced and Variant Bladder Cancer—An International Collaborative Multistakeholder Effort†

“…Since prospective or randomised controlled trials on brachytherapy are lacking, there was consensus among the expert panel not to recommend brachytherapy for MIBC. There was also a consensus not to recommend dose escalation by IMRT based on limited early results [47]. A UK-based randomised trial (RAIDER) addressing the potential value of dose escalation has just completed accrual and will provide further insights on this topic.…”

Prospective evaluation of definitive chemoradiotherapy with volumetric modulated arc therapy in patients with muscle invasive carcinoma of urinary bladder

“…Whally et al . evaluated the role of IMRT in MIBC [ 30 ]. However, this study included patients undergoing both RT alone and CRT, different RT fractionations were used and about 32% had previous BCG treatment.…”

A Pilot Study of Radiotherapy and Local Hyperthermia in Elderly Patients With Muscle-Invasive Bladder Cancers Unfit for Definitive Surgery or Chemoradiotherapy

“…With modern RT techniques, RT treatment planning and its delivery under online image guidance, the major late morbidities to the bladder and bowel have been reduced to <5% (7, 12, 38). This has allowed the exploration of various RT strategies e.g., hypofractionated RT.…”