Protocol for hypofractionated adaptive radiotherapy to the bladder within a multicentre phase II randomised trial: radiotherapy planning and delivery guidance

Bladder Preservation for Muscle-Invasive Bladder Cancer With Variant Histology

A growing body of evidence has shown bladder-preservation with chemo-radiotherapy achieves comparable survival to Radical Cystectomy (5-year OS 50%-70%) and superior quality of life outcomes for patients with muscle-invasive urothelial carcinoma of the bladder (UC). However, up to 55% of patients harbor variant histology and in this review we aim to clarify the role of bladder-preservation for this group. We first draw the distinction between urothelial carcinoma with divergent differentiation (UCDD) and non-urothelial carcinoma (NUC). UCDD is common, increasing in prevalence, and whilst each subtype may have its own characteristics current evidence suggests comparable outcomes with radical cystectomy and bladder-preservation. Non-urothelial carcinoma is a collection of distinct pathologies each deserving of its own management strategy. However, these tumors are rare, and evidence is generated from retrospective studies with significant inherent bias. Small cell carcinoma of the bladder has good evidence for bladder-preservation; however, other pathologies such as Squamous Cell Carcinoma and Adenocarcinoma are not well supported. We recommend careful multidisciplinary appraisal of the evidence for each subtype and honest patient discussion about the limited evidence before reaching management decisions. As we look to the future molecular-profiling may help better characterize these tumors and aid in treatment selection.

A Prospective Study of a Resorbable Intravesical Fiducial Marker for Bladder Cancer Radiation Therapy

Purpose

We conducted a prospective pilot study to evaluate safety and feasibility of TraceIT, a resorbable radiopaque hydrogel, to improve image guidance for bladder cancer radiation therapy (RT).

Methods and Materials

Patients with muscle invasive bladder cancer receiving definitive RT were eligible. TraceIT was injected intravesically around the tumor bed during maximal transurethral resection of bladder tumor. The primary endpoint was the difference between radiation treatment planning margin on daily cone beam computed tomography based on alignment to TraceIT versus standard-of-care pelvic bone anatomy. The Van Herk margin formula was used to determine the optimal planning target volume margin. TraceIT visibility, recurrence rates, and survival were estimated by Kaplan-Meier method. Toxicity was measured by Common Terminology Criteria for Adverse Events version 4.03.

Results

The trial was fully accrued and 15 patients were analyzed. TraceIT was injected in 4 sites/patient (range, 4-6). Overall, 94% (95% confidence interval [CI], 90%-98%) of injection sites were radiographically visible at RT initiation versus 71% (95% CI, 62%-81%) at RT completion. The median duration of radiographic visibility for injection sites was 106 days (95% CI, 104-113). Most patients were treated with a standard split-course approach with initial pelvic radiation fields, then midcourse repeat transurethral resection of bladder tumor followed by bladder tumor bed boost fields, and 14/15 received concurrent chemotherapy. Alignment to fiducials could allow for reduced planning target volume margins (0.67 vs 1.56 cm) for the initial phase of RT, but not for the boost (1.01 vs 0.96 cm). This allowed for improved target coverage (D_95% 80%-83% to 91%-94%) for 2 patients retrospectively planned with both volumetric-modulated arc therapy and 3-dimensional conformal RT. At median follow-up of 22 months, no acute or late complications attributable to TraceIT placement occurred. No patients required salvage cystectomy.

Conclusions

TraceIT intravesical fiducial placement is safe and feasible and may facilitate tumor bed delineation and targeting in patients undergoing RT for localized muscle invasive bladder cancer. Improved image guided treatment may facilitate strategies to improve local control and minimize toxicity.

Recognising the challenges of implementing multi-centre adaptive plan of the day radiotherapy

Two multicentre adaptive radiotherapy trials utilising Plan of the Day (PoD) with a library of plans were introduced in 35 centres. The common issues that arose from all centres when introducing PoD were collated retrospectively, through reviewing the data pertaining to the pre-trial and on-trial quality assurance programme. It was found that 1,295 issues arose when introducing PoD in outlining, planning, treatment delivery i.e., PoD selection, and in the overall process of delivering PoD. There was no difference in the number of issues that arose from pre-trial to on-trial. Thus, it is recommended that the implementation of PoD is supported by guidance, reviews, and continuous monitoring.

Role of radiotherapy in the management of bladder cancer: Recommendations of the French society for radiation oncology

We present the recommendations of the French society of oncological radiotherapy on the indications and techniques for external beam radiotherapy for bladder cancer.

Trends and Predictors of Hypofractionated and Intensity-Modulated Radiotherapy for Organ Preservation in Bladder Cancer

INTRODUCTION

Use of hypofractionated radiation (HFRT) and intensity-modulated radiation (IMRT) for organ preservation in bladder cancer is controversial and highly variable. We investigated practice patterns, trends, and predictors of HFRT and IMRT.

PATIENTS AND METHODS

The National Cancer Database was queried for patients with muscle-invasive, non-metastatic urothelial bladder cancer, treated with definitive (chemo)radiotherapy between 2004 and 2017. HFRT was defined as 50 to 60 Gy at >2 Gy/fraction. Multivariable logistic regression was used to identify predictors of receiving HFRT or IMRT. Multivariable Cox regression was used to model overall survival (OS), adjusting for potential confounders such as age, comorbidity, and chemotherapy.

RESULTS

Of 5132 patients identified, 490 (9.5%) received HFRT, and only 334 (6.5%) received ≥2.5 Gy/fraction. HFRT patients were significantly older, less fit, and less likely to receive chemotherapy relative to CFRT, even after controlling for age and comorbidity (adjusted odds ratio 0.36, 95% confidence interval [CI] 0.29-0.45, P < .0001). Utilization of HFRT and IMRT increased over time (P < .0001), reaching 22.5% and 47.7%, respectively, by 2017. Among patients treated with CFRT, OS was similar with or without IMRT (P = .46). Among patients treated with HFRT, IMRT was associated with increased survival (3-year OS 35% vs. 24%, P = .03), which persisted in multivariable analysis (adjusted hazard ratio 0.71, 95% CI 0.52-0.98, P = .04).

CONCLUSION

HFRT is largely underutilized, being primarily reserved for older, frailer patients. Chemotherapy is significantly underused with HFRT relative to CFRT. IMRT is used frequently and was associated with equivalent or modestly increased overall survival.

A practical approach to bladder preservation with hypofractionated radiotherapy for localised muscle-invasive bladder cancer

Bladder preservation with trimodality treatment (TMT) is an alternative strategy to radical cystectomy (RC) for the management of localised muscle invasive bladder cancer (MIBC). TMT comprises of transurethral resection of the bladder tumour (TURBT) followed by radiotherapy with concurrent radiosensitisation. TMT studies have shown neo-adjuvant chemotherapy with cisplatin-based regimens is often given to further improve survival outcomes. A hypofractionated radiotherapy regimen is preferable due to its non-inferiority in local control and late toxicities. Radiosensitisation can comprise concurrent chemotherapy (with gemcitabine, cisplatin or combination fluorouracil and mitomycin), CON (carbogen and nicotinomide) or hyperthermic treatment. Radiotherapy techniques are continuously improving and becoming more personalised. As the bladder is a mobile structure subject to volumetric changes from filling, an adaptive approach can optimise bladder coverage and reduce dose to normal tissue. Adaptive radiotherapy (ART) is an evolving field that aims to overcome this. Improved knowledge of tumour biology and advances in imaging techniques aims to further optimise and personalise treatment.

A 25-year perspective on the evolution of radiation treatment of urologic cancers

Advances in radiotherapy technology and technique over the last 3 decades have revolutionized radiation treatment options for genitourinary malignancies. The development of more focused and accurate radiation treatment has facilitated safe delivery of dose-escalated treatment that improves disease control and the development of shorter-duration hypofractionated treatment regimens that are more convenient for patients and improve access to treatment. The management of oligometastatic disease is evolving with ablative treatment of oligometastasis and the primary for select patients and shorter-duration palliative treatment regimens. Work is ongoing to personalize radiation treatment regimens for genitourinary malignancies based on molecular biomarkers.

The Development of Therapeutic Radiographers in Imaging and Adaptive Radiotherapy Through Clinical Trial Quality Assurance

AIMS

Adaptive radiotherapy (ART) is an emerging advanced treatment option for bladder cancer patients. Therapeutic radiographers (RTTs) are central to the successful delivery of this treatment. The purpose of this work was to evaluate the image-guided radiotherapy (IGRT) and ART experience of RTTs before participating in the RAIDER trial. A plan of the day (PoD) quality assurance programme was then implemented. Finally, the post-trial experience of RTTs was evaluated, together with the impact of trial quality assurance participation on their routine practice.

MATERIALS AND METHODS

A pre-trial questionnaire to assess the experience of the RTT staff group in IGRT and ART in bladder cancer was sent to each centre. Responses were grouped according to experience. The PoD quality assurance programme was implemented, and the RAIDER trial commenced. During stage 1 of the trial, RTTs reported difficulties in delivering PoD and the quality assurance programme was updated accordingly. A follow-up questionnaire was sent assessing experience in IGRT and ART post-trial. Any changes in routine practice were also recorded.

RESULTS

The experience of RTTs in IGRT and ART pre-trial varied. For centres deemed to have RTTs with more experience, the initial PoD quality assurance programme was streamlined. For RTTs without ART experience, the full quality assurance programme was implemented, of which 508 RTTs completed. The quality assurance programme was updated (as the trial recruited) and it was mandated that at least one representative RTT (regardless of pre-trial experience) participated in the update in real-time. The purpose of the updated quality assurance programme was to provide further support to RTTs in delivering a complex treatment. Engagement with the updated quality assurance programme was high, with RTTs in 24/33 centres participating in the real-time online workshop. All 33 UK centres reported all RTTs reviewed the updated training offline. Post-trial, the RTTs' experience in IGRT and ART was increased.

CONCLUSION

Overall, 508 RTTs undertook the PoD quality assurance programme. There was a high engagement of RTTs in the PoD quality assurance programme and trial. RTTs increased their experience in IGRT and ART and subsequently updated their practice for bladder cancer and other treatment sites.

Is Ultra Hypofractionated Radiation Therapy a Safe and Effective Treatment for Invasive Bladder Cancer in the Elderly?: A Retrospective Single Institution Review

PURPOSE

The aim was to determine the efficacy, safety, and tolerability of weekly ultra hypofractionated radiation therapy for older unfit patients with invasive bladder cancer.

METHODS

We retrospectively analyzed a cohort of patients with muscle invasive bladder cancer deemed unfit for chemoradiation therapy and thus treated with 6 weekly doses of 6 Gy using intensity modulated radiotherapy. Charlson comorbidity was calculated retrospectively. Cystoscopy and computed tomography were used to evaluate local control and toxicity using the common terminology criteria. Survival outcomes were estimated using the Kaplan-Meier method.

RESULTS

Twenty-two patients with a median age of 84 (range: 70 to 96) years were included. The median comorbidity index was 6±1.5 SD. Nineteen (90%) patients received the full 36 Gy dose. Median follow-up was 10±7 months (range: 6 to 27 mo). Local control in the bladder was achieved in 16 of 19 evaluable patients (84%). One-year overall survival was 62.5%, 1 patient had a retroperitoneal nodal recurrence and 3 patients developed distant metastasis. Grade 3 genitourinary and gastrointestinal toxicity was observed in 4 (18%) and 1 (4.5%) patients, respectively.

CONCLUSION

Weekly ultra hypofractionated intensity modulated radiotherapy with image guidance and bladder training is an effective, safe, and well-tolerated regimen for older patients with invasive bladder cancer unfit for radical treatment.

Recommendations for planning and delivery of radical radiotherapy for localized urothelial carcinoma of the bladder

PURPOSE

Curative radio-chemotherapy is recognized as a standard treatment option for muscle-invasive bladder cancer (MIBC). Nevertheless, the technical aspects for MIBC radiotherapy are heterogeneous with a lack of practical recommendations.

METHODS AND MATERIALS

In 2018, a workshop identified the need for two cooperative groups to develop consistent, evidence-based guidelines for irradiation technique in the delivery of curative radiotherapy. Two radiation oncologists performed a review of the literature addressing several topics relative to radical bladder radiotherapy: planning computed tomography acquisition, target volume delineation, radiation schedules (total dose and fractionation) and dose delivery (including radiotherapy techniques, image-guided radiotherapy (IGRT) and adaptive treatment modalities). Searches for original and review articles in the PubMed and Google Scholar databases were conducted from January 1990 until March 2020. During a meeting conducted in October 2020, results on 32 topics were presented and discussed with a working group involving 15 radiation oncologists, 3 urologists and one medical oncologist. We applied the American Urological Association guideline development's method to define a consensus strategy.

RESULTS

A consensus was obtained for all 34 except 4 items. The group did not obtain an agreement on CT enhancement added value for planning, PTV margins definition for empty bladder and full bladder protocols, and for pelvic lymph-nodes irradiation. High quality evidence was shown in 6 items; 8 items were considered as low quality of evidence.

CONCLUSION

The current recommendations propose a homogenized modality of treatment both for routine clinical practice and for future clinical trials, following the best evidence to date, analyzed with a robust methodology. The XXX group formulates practical guidelines for the implementation of innovative techniques such as adaptive radiotherapy.

Image-guided Adaptive Radiotherapy for Bladder Cancer

Technological advancement has facilitated patient-specific radiotherapy in bladder cancer. This has been made possible by developments in image-guided radiotherapy (IGRT). Particularly transformative has been the integration of volumetric imaging into the workflow. The ability to visualise the bladder target using cone beam computed tomography and magnetic resonance imaging initially assisted with determining the magnitude of inter- and intra-fraction target change. It has led to greater confidence in ascertaining true anatomy at each fraction. The increased certainty of dose delivered to the bladder has permitted the safe reduction of planning target volume margins. IGRT has therefore improved target coverage with a reduction in integral dose to the surrounding tissue. Use of IGRT to feed back into plan and dose delivery optimisation according to the anatomy of the day has enabled adaptive radiotherapy bladder solutions. Here we undertake a review of the stepwise developments underpinning IGRT and adaptive radiotherapy strategies for external beam bladder cancer radiotherapy. We present the evidence in accordance with the framework for systematic clinical evaluation of technical innovations in radiation oncology (R-IDEAL).

Clinical Outcomes of a Randomized Trial of Adaptive Plan-of-the-Day Treatment in Patients Receiving Ultra-hypofractionated Weekly Radiation Therapy for Bladder Cancer

PURPOSE

Hypofractionated radiation therapy can be used to treat patients with muscle-invasive bladder cancer unable to have radical therapy. Toxicity is a key concern, but adaptive plan-of the day (POD) image-guided radiation therapy delivery could improve outcomes by minimizing the volume of normal tissue irradiated. The HYBRID trial assessed the multicenter implementation, safety, and efficacy of this strategy.

METHODS

HYBRID is a Phase II randomized trial that was conducted at 14 UK hospitals. Patients with T2-T4aN0M0 muscle-invasive bladder cancer unsuitable for radical therapy received 36 Gy in 6 weekly fractions, randomized (1:1) to standard planning (SP) or adaptive planning (AP) using a minimization algorithm. For AP, a pretreatment cone beam computed tomography (CT) was used to select the POD from 3 plans (small, medium, and large). Follow-up included standard cystoscopic, radiologic, and clinical assessments. The primary endpoint was nongenitourinary Common Terminology Criteria for Adverse Events (CTCAE) grade ≥ 3 (≥G3) toxicity within 3 months of radiation therapy. A noncomparative single stage design aimed to exclude ≥30% toxicity rate in each planning group in patients who received ≥1 fraction of radiation therapy. Local control at 3-months (both groups combined) was a key secondary endpoint.

RESULTS

Between April 15, 2014, and August 10, 2016, 65 patients were enrolled (SP, n = 32; AP, n = 33). The median follow-up time was 38.8 months (interquartile range [IQR], 36.8-51.3). The median age was 85 years (IQR, 81-89); 68% of participants (44 of 65) were male; and 98% of participants had grade 3 urothelial cancer. In 63 evaluable participants, CTCAE ≥G3 nongenitourinary toxicity rates were 6% (2 of 33; 95% confidence interval [CI], 0.7%-20.2%) for the AP group and 13% (4 of 30; 95% CI, 3.8%-30.7%) for the SP group. Disease was present in 9/48 participants assessed at 3 months, giving a local control rate of 81.3% (95% CI, 67.4%-91.1%).

CONCLUSIONS

POD adaptive radiation therapy was successfully implemented across multiple centers. Weekly ultrahypofractionated 36 Gy/6 fraction radiation therapy is safe and provides good local control rates in this older patient population.

What is the Optimal Dose, Fractionation and Volume for Bladder Radiotherapy?

External beam radiotherapy (EBRT), as part of a trimodality approach, is an attractive bladder-preserving alternative to radical cystectomy. Several EBRT regimens with different treatment volumes have been described with similar tumour control and, so far, clear recommendations on the optimal radiotherapy regimen and treatment volume are lacking. The current review summarises EBRT literature on dose prescription, fractionation as well as treatment volume in order to guide clinicians in their daily practice when treating patients with muscle-invasive bladder cancer. Taking into account literature on repopulation, continuous-course radiotherapy can be used safely in daily practice where a split-course should only be reserved for those patients who are fit enough to undergo a radical cystectomy in case of a poor early response. A recent meta-analysis has proven that hypofractionated radiotherapy is superior to conventional radiotherapy with regards to invasive locoregional control with similar toxicity profiles. In the absence of node-positive disease, the target volume can be restricted to the bladder. In order to compensate for organ motion, very large margins need to be applied in the absence of image-guided radiotherapy (IGRT). Therefore, the use of IGRT or an adaptive approach is recommended. Based on the available literature, one can conclude that moderate hypofractionated radiotherapy to a dose of 55 Gy in 20 fractions to the bladder only, delivered with IGRT, can be considered standard of care for patients with node-negative invasive bladder cancer.

Comment on Hunt et al, "Feasibility of magnetic resonance guided radiotherapy for the treatment of bladder cancer"

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Bladder cancer patients who are unsuitable for standard radical treatments present a large unfulfilled clinical need.

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Hypofractionated RT can be an appropriate solution for these patients; however organ movement and changes in bladder filling is important obstacle for such treatment strategies.

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The only way to overcome this obstacle is that using online adaptive image-guided RT.

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There is need of new studies evaluating the role of MRgRT for bladder cancer patients.

Imaging and Management of Bladder Cancer

Simple Summary

Bladder cancer is a complex disease, the sixth most common cancer, and one of the most expensive cancers to treat. In the last few decades, there has been a significant decrease in the bladder cancer-related mortality rate, potentially related to decreased smoking prevalence, improvements in diagnosing bladder cancer, and advances in treatment. Those advances in diagnostic tools and therapies and greater understanding of the disease are helping to evolve how bladder cancer is managed. The purpose of this article is to provide a review of bladder cancer pathology, diagnosis, staging, radiologic imaging, and management, and highlight recent developments and research.

Abstract

Methods: Keyword searches of Medline, PubMed, and the Cochrane Library for manuscripts published in English, and searches of references cited in selected articles to identify additional relevant papers. Abstracts sponsored by various societies including the American Urological Association (AUA), European Association of Urology (EAU), and European Society for Medical Oncology (ESMO) were also searched. Background: Bladder cancer is the sixth most common cancer in the United States, and one of the most expensive in terms of cancer care. The overwhelming majority are urothelial carcinomas, more often non-muscle invasive rather than muscle-invasive. Bladder cancer is usually diagnosed after work up for hematuria. While the workup for gross hematuria remains CT urography and cystoscopy, the workup for microscopic hematuria was recently updated in 2020 by the American Urologic Association with a more risk-based approach. Bladder cancer is confirmed and staged by transurethral resection of bladder tumor. One of the main goals in staging is determining the presence or absence of muscle invasion by tumor which has wide implications in regards to management and prognosis. CT urography is the main imaging technique in the workup of bladder cancer. There is growing interest in advanced imaging techniques such as multiparametric MRI for local staging, as well as standardized imaging and reporting system with the recently created Vesicle Imaging Reporting and Data System (VI-RADS). Therapies for bladder cancer are rapidly evolving with immune checkpoint inhibitors, particularly programmed death ligand 1 (PD-L1) and programmed cell death protein 1 (PD-1) inhibitors, as well as another class of immunotherapy called an antibody-drug conjugate which consists of a cytotoxic drug conjugated to monoclonal antibodies against a specific target. Conclusion: Bladder cancer is a complex disease, and its management is evolving. Advances in therapy, understanding of the disease, and advanced imaging have ushered in a period of rapid change in the care of bladder cancer patients.

Protocol for tumour-focused dose-escalated adaptive radiotherapy for the radical treatment of bladder cancer in a multicentre phase II randomised controlled trial (RAIDER): radiotherapy planning and delivery guidance

INTRODUCTION

Daily radiotherapy delivered with radiosensitisation offers patients with muscle invasive bladder cancer (MIBC) comparable outcomes to cystectomy with functional organ preservation. Most recurrences following radiotherapy occur within the bladder. Increasing the delivered radiotherapy dose to the tumour may further improve local control. Developments in image-guided radiotherapy have allowed bladder tumour-focused 'plan of the day' radiotherapy delivery. We aim to test within a randomised multicentre phase II trial whether this technique will enable dose escalation with acceptable rates of toxicity.

METHODS AND ANALYSIS

Patients with T2-T4aN0M0 unifocal MIBC will be randomised (1:1:2) between standard/control whole bladder single plan radiotherapy, standard dose adaptive tumour-focused radiotherapy or dose-escalated adaptive tumour-focused radiotherapy (DART). Adaptive tumour-focused radiotherapy will use a library of three plans (small, medium and large) for treatment. A cone beam CT taken prior to each treatment will be used to visualise the anatomy and inform selection of the most appropriate plan for treatment.Two radiotherapy fractionation schedules (32f and 20f) are permitted. A minimum of 120 participants will be randomised in each fractionation cohort (to ensure 57 evaluable DART patients per cohort).A comprehensive radiotherapy quality assurance programme including pretrial and on-trial components is instituted to ensure standardisation of radiotherapy planning and delivery.The trial has a two-stage non-comparative design. The primary end point of stage I is the proportion of patients meeting predefined normal tissue constraints in the DART group. The primary end point of stage II is late Common Terminology Criteria for Adverse Events grade 3 or worse toxicity aiming to exclude a rate of >20% (80% power and 5% alpha, one sided) in each DART fractionation cohort. Secondary end points include locoregional MIBC control, progression-free survival overall survival and patient-reported outcomes.

ETHICS AND DISSEMINATION

This clinical trial is approved by the London-Surrey Borders Research Ethics Committee (15/LO/0539). The results when available will be disseminated via peer-reviewed scientific journals, conference presentations and submission to regulatory authorities.

TRIAL REGISTRATION NUMBER

NCT02447549; Pre-results.

Feasibility of magnetic resonance guided radiotherapy for the treatment of bladder cancer

Whole bladder magnetic resonance image-guided radiotherapy using the 1.5 Telsa MR-linac is feasible. Full online adaptive planning workflow based on the anatomy seen at each fraction was performed. This was delivered within 45 min. Intra-fraction bladder filling did not compromise target coverage. Patients reported acceptable tolerance of treatment.

Executive Summary of the American Radium Society Appropriate Use Criteria for Radiation Treatment of Node-Negative Muscle Invasive Bladder Cancer

PURPOSE

Definitive radiation therapy (RT), with or without concurrent chemotherapy, is an alternative to radical cystectomy for patients with localized, muscle-invasive bladder cancer (MIBC) who are either not surgical candidates or prefer organ preservation. We aim to synthesize an evidence-based guideline regarding the appropriate use of RT.

METHODS AND MATERIALS

We performed a Preferred Reporting Items for Systematic Reviews and Meta-analyses literature review using the PubMed and Embase databases. Based on the literature review, critical management topics were identified and reformulated into consensus questions. An expert panel was assembled to address key areas of both consensus and controversy using the modified Delphi framework.

RESULTS

A total of 761 articles were screened, of which 61 were published between 1975 and 2019 and included for full review. There were 7 well-designed studies, 20 good quality studies, 28 quality studies with design limitations, and 6 references not suited as primary evidence. Adjuvant radiation therapy after cystectomy was not included owing to lack of high-quality data or clinical use. An expert panel consisting of 14 radiation oncologists, 1 medical oncologist, and 1 urologist was assembled. We identified 4 clinical variants of MIBC: surgically fit patients who wish to pursue organ preservation, patients surgically unfit for cystectomy, patients medically unfit for cisplatin-based chemotherapy, and borderline cystectomy candidates based on age with unilateral hydronephrosis and normal renal function. We identified key areas of controversy, including use of definitive radiation therapy for patients with negative prognostic factors, appropriate radiation therapy dose, fractionation, fields and technique when used, and chemotherapy sequencing and choice of agent.

CONCLUSIONS

There is limited level-one evidence to guide appropriate treatment of MIBC. Studies vary significantly with regards to patient selection, chemotherapy use, and radiation therapy technique. A consensus guideline on the appropriateness of RT for MIBC may aid practicing oncologists in bridging the gap between data and clinical practice.