Overview of bladder cancer trials in the Radiation Therapy Oncology Group

In the United States, radical cystectomy is viewed as the gold standard and, with few exceptions, is the only treatment recommended for patients with invasive bladder cancer. In many areas of cancer treatment, however, the trend in the 1990s has been toward organ conservation using combined chemotherapy and radiation with or without conservative local surgery. For patients with breast, esophageal, anal, and laryngeal cancers as well as limb sarcomas, conservative therapy often is recommended. However, invasive bladder cancer has not been viewed generally as a condition that allows for conservative management. In the past 15 years, the Radiation Therapy Oncology Group (RTOG) has completed six prospective protocols of combined-modality therapy for patients with muscle-invasive cancer who were candidates for cystectomy. Bladder preservation with intravesical surgery, chemotherapy, and radiation therapy were combined as initial treatment, with radical cystectomy recommended for incomplete responders. Five of the RTOG protocols were Phase I-II trials of concurrent chemotherapy and radiation therapy, and one protocol was a Phase III trial that tested the efficacy of adjuvant chemotherapy with methotrexate, cisplatin, and vinblastine. A total of 415 patients were entered on these trials. The 5-year overall survival rate was approximately 50%, with three-quarters of those patients achieving a cure for their bladder cancer while maintaining a functioning bladder. The current RTOG protocol and its successor are directed toward better tolerated and potentially more effective chemotherapy regimens that may result in a high protocol compliance rate and, possibly, a higher overall survival rate. The trimodality therapeutic approach used in all of these RTOG protocols was more effective compared with the radiation monotherapy offered in the 1970s and with protocols that used only chemotherapy. Trimodality therapy with selective bladder preservation is not designed to take the place of radical cystectomy; however, it may be offered as a reasonable alternative to patients with invasive bladder cancer who are not willing to undergo radical cystectomy and urinary diversion. A bladder-sparing strategy may be offered appropriately to highly selected patients with the understanding that radical cystectomy is an available option in those who fail combined radiation and chemotherapy with no diminution in survival related to the delay in cystectomy.