Experience with cardiopulmonary bypass and deep hypothermic circulatory arrest in the management of retroperitoneal tumors with large vena caval thrombi. From June 1984 to September 1989, 43 patients with large vena caval tumor thrombi from retroperitoneal malignancies underwent surgical treatment with cardiopulmonary bypass (CPB) and deep hypothermic circulatory arrest (DHCA). The primary malignancies were renal cell carcinoma (RCC) (n = 39), renal pelvic transitional cell carcinoma (n = 1), adrenal pheochromocytoma (n = 1), and renal (n = 1) or retroperitoneal (n = 1) sarcoma. The level of the caval thrombus was either suprahepatic (n = 27), intrahepatic (n = 14), or subhepatic (n = 2). In all cases the primary tumor and caval thrombus were completely removed. Concomitant procedures included coronary artery bypass grafting (n = 5), pulmonary resection (n = 2), and hepatic lobectomy (n = 1). The time of circulatory arrest ranged from 10 to 44 minutes (mean, 23.5 minutes). There were two operative deaths (4.7%), neither of them due to to the use of DHCA. Major postoperative complications occurred in 13 patients (30.2%). There were no ischemic or neurologic complications and no cases of perioperative tumor embolization. The median postoperative hospital stay was 9 days. Twenty-two patients (51%) are alive and enjoying a good quality of life. The 3-year patient survival rates in patients with localized (n = 24) versus metastatic (n = 15) RCC are 63.9% and 10.9%, respectively (p = 0.02). We conclude that CPB with DHCA facilities excision of retroperitoneal malignancies with large caval thrombi and provides the potential for cure with low morbidity and mortality rates. 