From 1982 to 1985, 225 patients with renal cell carcinoma were treated by nephrectomy. To evaluate the diagnostic significance of ultrasonography in predicting tumor stage the results of ultrasonography, computerized tomography, renal angiography and excretory urography were compared to the histopathological findings. Since local tumor extension has a considerable impact on the operation strategy evaluation of the T classification was of particular interest. All 4 diagnostic procedures were performed in 73 of the 225 patients. The T stage was determined correctly by ultrasonography in 77.8 per cent of the patients, while the tumor was not identifiable in only 0.6 per cent. Computerized tomography was almost as reliable as ultrasonography (the T stage was predicted correctly in 72.3 per cent of the examinations). In contrast, the tumor was staged correctly by angiography in only 57.2 per cent of the patients and by excretory urography in only 59.2 per cent. From these results ultrasonography appears to be an effective, noninvasive, inexpensive and safe procedure to evaluate the T stage of renal tumors.

In order to evaluate the antiproliferative effects of recombinant human interferon-Γ_2c (rHu IFN-Γ_2c), recombinant human interferon-Γ (rHu IFN-Γ), natural interferon-Β (IFN-Β), and their combination with cytotoxic agents, 17 different human bladder carcinoma cell lines were tested in vitro. The antiproliferative effects were compared in evaluating the tumor cell inhibiting potency of the different interferon (IFN) classes. It could be demonstrated that interferons have inhibiting effects on the bladder cancer cell multiplication rate, yet there are significant differences in the susceptibility of different IFN preparations on different cell lines. The cell lines BT1, RT4, EJ, 468P, 253J, SD, TCCSUP, and SW1738 can be defined as sensitive, T24, 647V, VM-CUB2, and J82 as semisensitive, HT1376, 5637, VM-CUB1, 639V and SW1710 as resistant upon treatment with IFN. The combination of rHu IFN-Α_2c, IFN-Β, and rHu IFN-Γ seems to be more effective than treatment with rHu IFN-Α_2c alone. The cytotoxic effect of doxorubicin on bladder cancer cells can be intensified by combining it with IFN.

In previous investigations, it was demonstrated that interferons (IFN) have antiproliferative effects in human urothelial carcinomas. However, appreciable differences were found in the sensitivity of the individual tumors investigated. We therefore examined whether this might be due to a different receptor status of the cells. The IFN-sensitive cell lines RT4 and SD as well as the IFN-resistant cell line 639V were investigated with regard to their IFN receptor status. It was demonstrated that IFN receptors were present on the cell surface in all three urothelial carcinomas investigated. The number of IFN receptors calculated for the IFN-resistant cell line 639V was 4.661 per cell, whereas the IFN-sensitive cell line SD had 4.391 receptors and RT4 had 3.307 receptors. The IFN affinity of the three cell lines tested differed only slightly. Therefore IFN affinity is unlikely to account for their marked differences in IFN sensitivity.

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The treatment of metastatic renal carcinoma is still unsatisfactory because of the lack of effective systemic therapy. In 14 patients with metastatic renal carcinoma an attempt was made to influence the course of the disease by administration of recombinant human interferon (rHu-IFN) gamma; 9 patients were evaluated after treatment. There was partial remission in 3 patients, stable disease in 2 and tumour progression in 4. The cyclic application of rHu-IFN at a dose of 0.25 mg/day for 8 days, with treatment-free intervals of 3 to 4 weeks, was tolerated well. Side effects consisted mainly of fever and leucocytopenia. From this small series it seems that cyclic IFN gamma treatment might be helpful in some cases of metastatic renal carcinoma.