The purpose of this study was to work out an adequate operative technique for patients with malignant tumors who also need open heart surgery or procedures on major blood vessels. We had 8 such patients. In 6 of them, a tumor (3 cases hypernephroid cancer and 3 cases retroperitoneal sarcoma) had grown through the inferior vena cava (IVC) up to the right atrium. Two patients had lung cancer together with severe coronary artery disease. All of these patients were operated on using a heart-lung machine (HLM) and cell saver (CS). In 6 patients the intravascular portion of the tumor was extracted as much as possible through a right atrium approach (in 3 cases a nephrectomy was performed). Two patients had a one-stage coronary artery bypass graft (CABG) and a lobectomy. All of the patients had uneventful postoperative periods and were alive when checked on 1 year after the procedures. During cytological investigation after each operation, tumor cells were found only on the internal surface of the HLM arterial filters with 20 microns holes. We suggest that special cardiovascular devices such as the HLM and CS might be used in borderline situations in oncology without increasing the risk of hematogenous tumor dissemination.