Combined intraarterial cisplatin infusion and radiation therapy were performed as the initial treatment for 23 patients (mean age: 70 years) with invasive bladder cancers (T2 in 17, T3 in 6) who were suitable for total cystectomy. Of these patients, five who had multiple invasive cancers without laterality had their intrapelvic hemodynamics altered by embolizing a contralateral internal iliac artery. Cisplatin (50 mg) was infused into the internal iliac artery through a subcutaneous reservoir twice a week over three weeks while concurrent radiation therapy with 30 Gy, delivered in 15 fractions, was performed. Additional cisplatin infusions were given in six patients. After this combined therapy, total cystectomy and ileal conduit was performed in six patients and transurethral resection of bladder tumor (TURBT) in 17. Two of the patients who underwent total cystectomy were found to exhibit a complete response. Therefore, the overall response rate was 87%, including 13 complete responses and seven partial responses. The complete response rates in patients with clinical stage T2 and T3 disease were 53 and 67%, respectively. The complete response rate was slightly higher in patients with a non-papillary cancer than in those with a papillary one. Toxic reactions included a decrease in bladder capacity in two patients and severe diarrhea due to methicillin-resistant Staphylococcus aureus colitis in one. Other forms of toxicity, including nausea, vomiting, neurotoxicity in the gluteal region, nephrotoxicity and myelosuppression, were tolerable. All but one of the patients are alive.(ABSTRACT TRUNCATED AT 250 WORDS)