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TOPLINE:

Among patients undergoing radical cystectomy and perioperative chemotherapy for high-risk muscle-invasive bladder cancer (MIBC), adjuvant radiotherapy cut locoregional recurrence risk by more than half — with numeric improvements in disease-free and overall survival.

METHODOLOGY:

• Locally advanced MIBC is treated with neoadjuvant chemotherapy followed by radical cystectomy and pelvic nodal dissection, yet about half of patients have disease recurrence within 3 years. Adjuvant radiotherapy can improve pelvic disease control and, with modern intensity-modulated radiotherapy (IMRT) planning, may do so more safely.
• Researchers conducted a phase 3 randomized controlled trial across four academic centers in India, enrolling 153 patients with nonmetastatic MIBC at high risk after radical cystectomy. Nearly all received chemotherapy (71% neoadjuvant, and 20% adjuvant). Patients were randomly assigned to either adjuvant radiotherapy (n = 77) or observation (n = 76).
• Radiotherapy consisted of stoma-sparing image-guided IMRT delivering 50.4 Gy in 28 fractions to the cystectomy bed and pelvic nodes, starting within 8 weeks of surgery or last cycle of adjuvant chemotherapy.
• The primary outcome was 2-year locoregional recurrence-free survival, with secondary end points including disease-free survival, bladder cancer-specific survival, and overall survival. Median follow-up duration was 47 months.

TAKEAWAY:

• At 2 years, locoregional recurrence-free survival was significantly higher with adjuvant radiotherapy, at 87.1% vs 76.0% with observation (hazard ratio, 0.43; P = .04).
• The radiotherapy arm also showed numeric improvements in disease-free survival (71.6% vs 58.7%), bladder cancer-specific survival (79.6% vs 65.0%), and overall survival (70.4% vs 57.4%) — but those figures fell short of statistical significance.
• Of 60 patients with disease recurrence, about 31% had distant metastases, with similar rates in both groups. Locoregional recurrence was significantly lower with pelvic radiotherapy: 7.9% vs 25.6% in the observation arm (odds ratio, 0.25).
• Serious adverse events in the first 3 months were uncommon (1.6% of radiotherapy patients vs 4.2% of those in the observation arm). Overall, 17.5% of radiotherapy patients had grade 2 symptoms such as diarrhea or proctitis. Late grade 3 or 4 events occurred in 17% and 10.5% of patients in the radiotherapy and observation arms, respectively.

IN PRACTICE:

The results suggest that adjuvant pelvic IMRT improves locoregional control in this patient population, the study authors wrote. “With minimal added severe toxicity, its addition to the standard-of-care adjuvant treatment for patients with high-risk MIBC is strengthened,” they concluded.

SOURCE:

The study, led by Vedang Murthy, MD, of Tata Memorial Centre, Mumbai, India, was published online in the Journal of Clinical Oncology.

LIMITATIONS:

Fourteen patients assigned to the radiotherapy arm did not receive the planned intervention, which may inflate the treatment effect observed in the per-protocol analyses of secondary end points. None of the patients received immunotherapy during the trial, which may affect applicability to current practice in some settings.

DISCLOSURES:

The study was funded by Tata Memorial Centre. Murthy and several co-authors reported financial relationships with various commercial sources. Full disclosures are noted in the original article.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.