Blood flow to experimental renal tumors

Radiolabeled microsphere techniques were used to measure renal blood flow (RBF) in rabbit kidneys with 14- to 16-day-old experimentally induced renal tumors. VX-2 carcinoma cells (25 microliters) harvested from carrier animal intramuscular tumors were injected supraselectively into an intralobar artery using fluoroscopically guided transcatheter techniques. Within 2 to 3 weeks, all animals developed localized 10 to 25 mm diameter renal tumors. Renal blood flow was calculated after left ventricular injection of 113Sn-labeled 15 mu diameter microspheres. Blood flow (ml/minute) in tumor-bearing kidneys (26.91 +/- 1.86) was significantly lower (P = less than .05) than in normal controls (49.79 +/- 7.71). The tumor-bearing kidneys were also significantly larger (15.21 +/- 1.27 gm) than control animal kidneys (10.89 +/- 0.071 gm). Analysis of the tumor kidneys showed flow (ml/minute/g) in the tumor-containing sections (1.82 +/- 0.15) and in the actual tumor tissue (0.62 +/- 0.07) to be significantly lower (P = less than .05) than (1) in the nontumor portions of the same kidneys (2.58 +/- 0.28), and (2) in the tumor animals' contralateral nontumor-bearing kidneys (3.22 +/- 0.16), and (3) in normal control animal kidneys (4.54 +/- 0.29). The reduced flow in tumor-bearing kidneys was not an artifact due to arteriovenous shunting, as demonstrated by 99mTc-microsphere studies in four additional tumor-bearing animals. This study has shown that blood flow to the tumor is extremely low compared with nontumor-containing ipsilateral, contralateral, and normal control renal tissue. These results provide important information relative to possible experimental therapeutic research involving embolization or pharmacologic manipulation of the blood supply to potentiate intra-arterial chemotherapy.