ASTRO Issues First Standalone Guideline on Radiation Therapy for Bladder Cancer
Key Insights
ASTRO released its first standalone clinical practice guideline on radiation therapy for bladder cancer, published in Practical Radiation Oncology and developed with ASCO, EAU and ESTRO.
The guideline strongly recommends trimodal therapy as an alternative to radical cystectomy for select patients with cT2-4aN0M0 muscle-invasive bladder cancer (search).
Recommendations also cover adjuvant radiation after cystectomy, dose-fractionation schedules, and palliative or consolidative radiation in metastatic disease.
The American Society for Radiation Oncology (search) (ASTRO) has issued its first clinical practice guideline focused specifically on radiation therapy across the full spectrum of bladder cancer care, supporting bladder preservation as a curative option for appropriately selected patients with muscle-invasive disease rather than defaulting to surgical removal of the bladder.
The guideline, "Radiation Therapy for Bladder Cancer: An ASTRO Clinical Practice Guideline," was published in Practical Radiation Oncology, ASTRO's clinical practice journal. It was developed by a multidisciplinary task force of radiation, medical and urologic oncologists, a medical physicist and a patient representative, based on a systematic review of research published from 2009 through 2024. Development was conducted in collaboration with the American Society of Clinical Oncology (ASCO), the European Association of Urology (EAU) and the European Society for Radiotherapy and Oncology (search) (ESTRO), and the guideline was endorsed by the EAU and ESTRO.
The document addresses four key clinical questions spanning curative-intent bladder preservation through trimodal therapy (TMT), radiation therapy techniques and dose-fractionation, postoperative radiation following cystectomy, and palliative and consolidative radiation in metastatic disease.
Bladder Preservation as a Curative Option
For appropriately selected patients with cT2-4aN0M0 muscle-invasive bladder cancer (search) (MIBC), the guideline offers a strong recommendation that trimodal therapy is a recommended alternative to radical cystectomy. TMT combines maximal transurethral resection of the bladder tumor (TURBT), an endoscopic procedure performed through the urethra, followed by radiation therapy with concurrent radiosensitizing systemic therapy.
Favorable features for bladder preservation include a solitary tumor smaller than 7 centimeters, predominant urothelial carcinoma histology, and the absence of extensive carcinoma in situ or hydronephrosis. Long-term studies and observational comparisons suggest that carefully selected patients treated with trimodal therapy can achieve cancer outcomes similar to those seen with radical cystectomy, with the potential to retain a functioning bladder.
"Bladder preservation should be presented as a curative treatment option alongside radical cystectomy for appropriately selected patients with muscle-invasive bladder cancer (search)," said guideline task force chair Jason A. Efstathiou, MD, DPhil, a radiation oncologist at Mass General Brigham Cancer Institute (search) and professor of radiation oncology at Harvard Medical School. "This guideline gives multidisciplinary teams practical guidance on patient selection and safe treatment delivery, with decisions guided by each patient's disease, overall health and priorities."
Concurrent radiosensitizing systemic therapy during TMT is strongly recommended, with chemotherapy preferred. Recommended regimens include cisplatin with or without 5-fluorouracil (5-FU), 5-FU plus mitomycin C, or low-dose gemcitabine. For patients at higher risk of distant metastatic progression, such as those with cT3-4 or N1-3 disease, neoadjuvant or induction systemic therapy before TMT is also strongly recommended. Patients receiving trimodal therapy should undergo cystoscopic assessment after treatment and continued surveillance for recurrence.
For patients with high-grade cT1N0M0 non-muscle-invasive bladder cancer (search) (NMIBC) who experience T1 recurrence despite intravesical or systemic therapies and who decline or are ineligible for cystectomy, TMT or enrollment in a clinical trial is conditionally recommended. A prospective trial (NCT00981656) in this population demonstrated a 3-year cystectomy-free rate of 88% with chemoradiation.
Radiation Planning, Dosing and Delivery
For patients with intact, localized or node-positive bladder cancer, intensity-modulated radiation therapy (IMRT) with daily image guidance using cone-beam CT is strongly recommended to verify bladder volume and target localization. Whole bladder radiation to full dose or a partial tumor boost are both recommended, while elective pelvic nodal radiation is conditionally recommended based on higher-risk clinical features including cT3-4 disease, hydronephrosis, aggressive histologic subtypes or lymphovascular invasion.
Recommended dose-fractionation regimens include moderately hypofractionated radiation at 55 Gy in 20 fractions, or conventionally fractionated radiation at 64 to 64.8 Gy in 32 to 36 fractions. A continuous course without a mid-treatment break is strongly recommended, superseding the historical practice of interim cystoscopy during a radiation break. Dose escalation above 64 to 64.8 Gy is not recommended outside of a clinical trial. Adaptive radiation techniques are conditionally recommended where standard planning cannot meet target coverage and organ-at-risk constraints.
Two ongoing trials are cited in the guideline. The randomized controlled phase 3 ARCHER trial (NCT07097142) is evaluating adaptive 5-fraction ultrahypofractionated radiation versus moderately hypofractionated radiation, both with concurrent chemotherapy, in localized bladder cancer. The SWOG/NRG 1806 trial (NCT03775265) is evaluating whether adding atezolizumab (Tecentriq) to standard chemoradiation improves outcomes in MIBC managed with bladder-preserving TMT.
Adjuvant Radiation After Cystectomy
For patients with urothelial carcinoma who have (y)pT3-4 or (y)pN+ disease or positive surgical margins following radical cystectomy, adjuvant radiation therapy is conditionally recommended for locoregional control. The recommendation is supported by evidence from three randomized controlled trials demonstrating clinically meaningful and statistically significant improvements in local control. Target volumes should routinely include the cystectomy bed and pelvic lymph nodes.
The recommended adjuvant dose is 44 Gy to 50.4 Gy in 22 to 28 fractions; for positive margins, a simultaneous integrated boost (SIB) to up to 56 Gy may be added when anatomically feasible. IMRT with daily cone-beam CT imaging is strongly recommended, and a neobladder reconstruction is not a contraindication to adjuvant radiation. Initiating adjuvant radiation within 2 to 3 months of cystectomy, or within 8 weeks of completing adjuvant chemotherapy, is strongly recommended, with a delay of up to 4 months acceptable in patients with neobladders working to achieve continence.
"The role of radiation therapy in bladder cancer extends well beyond bladder preservation," said guideline task force vice chair Leslie K. Ballas, MD, a radiation oncologist at Cedars-Sinai. "The recommendations clarify when radiation therapy may improve local control after cystectomy and how it can be used to relieve or prevent symptoms for patients with advanced disease, giving multidisciplinary teams a clear framework to integrate radiation throughout bladder cancer care."
Palliative and Metastatic Disease
For patients with high-burden metastatic and locally symptomatic bladder cancer, or locoregional disease managed with noncurative intent, bladder-directed radiation for local control and/or palliation is strongly recommended. Palliative dose-fractionation options include 21 Gy in 3 fractions given on alternate days, 34.5 Gy to 36 Gy in 6 weekly fractions, or shorter schedules such as a single fraction of 6 Gy to 8 Gy, 20 Gy in 5 fractions, or 30 Gy in 10 fractions.
For patients with low-burden metastatic disease, defined as 5 metastatic sites or fewer, who respond to systemic therapy, bladder-directed consolidative radiation is conditionally recommended. Ablative, metastasis-directed radiation for oligometastatic or oligoprogressive disease is also conditionally recommended based on limited but growing evidence. Conversely, consolidative bladder radiation is not recommended for asymptomatic patients with high-burden metastatic disease, defined as 5 or more metastases.
Disease Burden and Disparities
Although bladder cancer incidence has declined modestly over the past decade, it remains the fifth most commonly diagnosed cancer among U.S. men, occurring about four times more often in men than in women. In 2026, an estimated 85,000 U.S. adults will be diagnosed with bladder cancer, and approximately 18,000 will die from the disease.
Radical cystectomy has long been a standard curative treatment for muscle-invasive bladder cancer (search), typically combined with systemic therapy, and requires creating a new way for urine to leave the body. The operation may not be appropriate for some patients because of frailty or other health conditions, while others may prefer to preserve their bladder.
The guideline dedicates a section to health disparities in bladder cancer care, noting that patients who are Black with MIBC are less likely to receive definitive curative-intent treatment including cystectomy or chemoradiation. Geographic factors further compound inequities, with rural populations experiencing higher mortality and reduced access to specialized cancer centers. The task force calls for broader access to evidence-based treatment, expansion of access to high-volume centers and multidisciplinary clinics, and greater inclusion of populations historically underrepresented in bladder cancer research.
ASTRO notes that its clinical guidelines are intended as tools to promote appropriately individualized, shared decision-making between physicians and patients, and should not be construed as strict or superseding the appropriately informed and considered judgments of individual physicians and patients.