Medically fragile patients with muscle-invasive bladder cancer (MIBC) who cannot tolerate surgery still might respond to less aggressive chemoradiation while keeping their bladders, investigators suggest.
In NRG Oncology RTOG 0524, investigators assigned 65 patients ineligible for radical cystectomy and cisplatin-based chemotherapy to alternative chemotherapy with a lower risk of renal toxicity plus transurethral resection of bladder tumor (TURBT). The diagnosis for 85% was T2 disease. A total of 45 patients received weekly paclitaxel for 7 weeks and daily radiation to the bladder and pelvis (group 2). The remaining 20 patients with her2/neu overexpression in their tumors also received weekly trastuzumab for a total of 7 doses (group 1). Median follow-up duration was 2.3 years for all patients and 7.2 years for surviving patients.
Protocol therapy was completed by 60% of patients in group 1 and 76% of those in group 2. The complete response rate at 12 weeks was 62% in both groups.
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Overall survival at 5 years was 25.0% in group 1 and 37.8% in group 2, Douglas M. Dahl, MD, of Massachusetts General Hospital Cancer Center in Boston, Massachusetts, and colleagues reported in European Urology Oncology. Disease-free survival at 5 years was 15.0% in group 1 and 31.1% in group 2.
“The majority of the patients had a complete response to therapy,” the investigators wrote. “Despite this, 65% of patients had recurred or died by year 2.”
Grade 3 or higher acute treatment-related adverse events (AEs) occurred in 80% of patients in group 1 and 58% in group 2. One patient in group 1 had a treatment-related grade 5 death. Gastrointestinal toxicity was the most common AE and likely related to both paclitaxel and radiation, according to the investigators. The rate of unresolved acute treatment-related toxicity was 35% in group 1 and 31% in group 2.
“Long-term tumor control appears inferior to more standard treatments available to medically fit patients,” according to Dr Dahl’s team. “Newer radiation fractionations and technologies, immunotherapeutic medication, and nonchemotherapy radiation adjuvants that have been studied may offer either an improved therapeutic response or better tolerability and convenience.”
Disclosure: Some study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors’ disclosures.
Reference
Dahl DM, Karrison TG, Michaelson MD, et al. Long-term outcomes of chemoradiation for muscle-invasive bladder cancer in noncystectomy candidates. Final results of NRG Oncology RTOG 0524-A Phase 1/2 Trial of paclitaxel + trastuzumab with daily radiation or paclitaxel alone with daily irradiation. Eur Urol Oncol. Published online July 11, 2023. doi:10.1016/j.euo.2023.05.01