KEY POINTS
- ASTRO developed the guideline through a systematic evidence review and multidisciplinary consensus process addressing four areas: bladder preservation, definitive RT technique and fractionation, postcystectomy RT, and noncurative treatment.
- For selected cT2–4aN0M0 muscle-invasive bladder cancer, trimodal therapy consisting of maximal TURBT followed by chemoradiation is a strong recommendation supported by high-quality evidence as an alternative to radical cystectomy. Favorable features include solitary tumors, size <7 cm, predominant urothelial histology, no extensive CIS, and no hydronephrosis.
- Concurrent radiosensitizing systemic therapy is recommended. Established options include cisplatin with or without 5-FU, 5-FU plus mitomycin C, and low-dose gemcitabine; neoadjuvant or induction systemic therapy is recommended when distant-progression risk is higher.
- For bladder-only chemoradiation in cT1–4N0M0 disease, ASTRO strongly recommends either 55 Gy in 20 fractions or 64–64.8 Gy in 32–36 fractions. A planned mid-treatment cystoscopic break is not recommended.
- For clinically node-negative disease, either bladder-only treatment or inclusion of elective pelvic nodes may be used. Elective nodal irradiation is more reasonable with higher-risk features such as cT3–4 disease, hydronephrosis, extensive tumor, lymphovascular invasion, incomplete TURBT, or suspicious nodes.
- IMRT/VMAT with daily cone-beam CT to verify bladder volume is recommended. Dose escalation above 64–64.8 Gy is not recommended outside a clinical trial or multi-institutional registry.
- After cystectomy, adjuvant RT is conditionally recommended for urothelial carcinoma with (y)pT3–4 disease, (y)pN+ disease, or positive margins to improve locoregional control. Bladder-directed RT is also recommended for local control or palliation in symptomatic disease treated with noncurative intent.
CLINICAL TAKEAWAY
ASTRO places modern bladder-preserving chemoradiotherapy firmly alongside cystectomy for appropriately selected muscle-invasive disease and provides unusually concrete guidance on fractionation, volumes, radiosensitization, and IGRT. The strength of evidence varies outside localized MIBC, particularly for elective nodes and postoperative RT.