Blood flow to experimental renal tumors

Effect of renal embolization in patients with synchronous metastatic renal cell carcinoma: a retrospective comparison of cytoreductive nephrectomy and systemic medical therapy

Objective

To compare survival outcomes for renal embolization (RE) to cytoreductive nephrectomy (CN) and no primary renal treatment (NT) among patients with synchronous metastatic renal cell carcinoma (mRCC) treated using either targeted therapy (TT) or immunotherapy (IT).

Results

The median follow-up duration was 81.3 months, with a duration of first-line treatment of 3.5 months. Among the 211 patients, the median PFS and OS were 4.4 and 10.6 months. Specifically for patients receiving TT (124 patients), the PFS and OS were 5.5 and 12.0 months. An intervention effect was identified only for OS, with a median OS of 20.1, 8.8 and 9.3 months for CN, RE and NT, respectively. After stratification by risk classification, CN provided a significant benefit on OS, compared to RE and NT, for patients with an intermediate risk (MSKCC). For those with a poor risk (Heng criteria), NT provided better survival than PFS (p=0.003), and a comparable survival to RE (p > 0.05).

Materials and Methods

Retrospective analysis of 211 patients, 87 treated with IT and 124 with TT, retrieved from our RCC database. Patients' risk factors for survival was evaluated using the Heng and MSKCC criteria, with only patients with an intermediate or poor survival risk included in the analysis. Between-group comparisons were evaluated with respect to progression-free survival (PFS) and overall survival (OS).

Conclusions

The differential effect of CN and RE on OS appears to be modulated by risk classification. In patients with a poor risk, RE should be implemented after careful consideration of comorbidities and life expectancy.

Intraarterial Doxorubicin Infusion Treatment with and without Occlusion of the Renal Artery in Rabbit Renal VX-2 Carcinoma

The aim of this investigation was to establish an animal model for studying fractionated intraarterial treatment of a rabbit kidney VX-2 carcinoma. As repeated catheterizations and drug infusions may cause vascular lesions, we wanted to find whether the rabbit renal artery could be catheterized several times within a short period of time with acceptable iatrogenic vascular trauma. Each of 3 groups of rabbits with implanted renal VX-2 carcinoma were treated 3 times with either 1) temporary renal artery occlusion combined with infusion (occlusion infusion) of a) physiologic saline (OIS) or b) doxorubicin (OID), or 2) with renal artery infusion of doxorubicin. OID was administered in 20 of 21 attempts, OIS in 21 of 24, and infusion of doxorubicin in 20 of 21 attempts. Renal arterial spasm was seen in 5 of 22 rabbits, rarely at the first catheterization, more frequently during the second and third. Permanent iatrogenic vascular trauma occurred in 4 of 15 rabbits after the second and third occlusion infusion. We conclude that the rabbit kidney with implanted VX-2 carcinoma may be a useful model for testing fractionation schemes for multiple intraarterial infusions of antineoplastic drugs.

Effect of Ethanol Induced Occlusion of the Renal Artery in Rabbit Kidney Implanted with VX2 Carcinoma

The effects of injection of absolute ethanol into the renal artery were investigated in 13 rabbit kidneys previously implanted with VX2 carcinoma. Eight rabbits with implanted tumors served as controls. The effects were evaluated by angiography and histology. Three days after implantation, tumors were demonstrated by angiography as relatively hypovascular areas in the subcapsular cortex of the kidneys. Following angiography, absolute ethanol (0.3 ml/kg) was injected into the renal artery. Repeat angiography with barium sulphate was performed after an additional 3 days (10 ethanol treated animals, 2 controls), 10 days (2 treated, 1 control) or 14 days (1 treated, 0 control). In treated animals the tumors were markedly smaller in comparison with those of the control group. The occlusion procedure, however, did not completely eradicate tumor cells. The histologic study of the implanted tumor confirmed the findings previously reported that viable tumor cells still remained in the peripheral portions of infarcted areas. This study demonstrated the beneficial, though not curative, short-term effects of transcatheter renal artery treatment with absolute ethanol in malignant renal tumors.

The influence of microvessel density on ovarian carcinogenesis

OBJECTIVE

Tumor microvessel density, measured by CD31 immunohistochemistry, correlates with survival in patients with ovarian cancer. CA 125 is secreted by most ovarian cancers, and we have previously shown that the rate of decline of CA 125 is also predictive of ovarian cancer survival. Because increased tumor vascularity may allow metastases on one hand, while facilitating the delivery of chemotherapy on the other, we investigated the relationship of tumor microvessel density to preoperative CA 125, residual disease, and the initial response to treatment.

METHODS

FIGO stage, grade, age, residual disease, and CD31 microvessel density count were correlated with consecutive patients (n = 202) diagnosed with epithelial ovarian cancer who met entry criteria. The relationship of CD31 staining to preoperative CA 125, and the rate of decline in CA 125 (slope) as a measure of initial response to therapy, was also evaluated based on complete CA 125 data. Spearman correlation and the Wilcoxon rank sum test were used for bivariate analyses. Linear and logistic regression was used for multivariate analysis.

RESULTS

There were 21 stage I, 14 stage II, 125 stage III, and 42 stage IV patients diagnosed with epithelial ovarian cancer included in the study. More than half (N = 126) of the patients were optimally cytoreduced. Elevated microvessel density was associated with advanced stage of disease (P = 0.0453), grade (P = 0.0002), and an increased amount of residual disease (P = 0.0144). CA 125 values were higher in patients with residual disease versus patients without residual disease (P = 0.0357), and the decline in the CA 125 (slope) was less steep in patients without residual disease versus patients with residual disease (P = 0.0003). However, the initial response to chemotherapy was unrelated to the microvessel density count as measured by CD31 antibody staining (P = 0.7911). In multivariate analyses, CD31 counts remained significant in relationship to grade. Nonideal slopes, indicating decreased response, were associated with increasing age (P = 0.0008) and residual disease (P = 0.0035).

CONCLUSION

Elevated ovarian cancer microvessel density count is related to advanced stage and grade of disease, and compromised potential for cytoreduction. Residual disease is associated with higher CA 125 levels and faster CA 125 decline rates. The rate of decline of CA 125 during the initial response to treatment cannot be predicted based on CD31 counts, confirming a complex relationship between tumor vascularity, metastasis, and response to treatment.

Functional CT imaging of angiogenesis in rabbit VX2 soft-tissue tumour

Functional parameters such as blood flow (BF), microvessel permeability surface area product (PS), blood volume (BV) and mean transit time (MTT) are physiological markers related to the changes associated with angiogenesis. In the current study we present a functional CT technique for the simultaneous measurement of these four functional parameters and the display of each parameter as a functional image over an entire tissue slice. New Zealand White rabbits with implanted VX2 thigh tumours were scanned using CT with contrast media injection. The ex vivo method of radioactive microspheres was used to evaluate the accuracy of BF measurements with the functional CT technique. There was a significant linear correlation (R = 0.96) between regional CT and microsphere-measured BF values, with a slope not significantly different from unity (0.98 +/- 0.02, P < 0.0001). The precision of our CT technique was determined by the repeated scanning under steady-state conditions. The precision of CT-measured BF, PS. BV and MTT was 14%, 18%, 20% and 24%, respectively. In conclusion, BF can be measured accurately and BF, PS, BV and MTT reproducibly using our functional CT technique. Functional CT can be readily incorporated into existing imaging protocols to assess tumour angiogenesis.

Comparison of nephrectomy and/or doxorubicin treatment in rabbit renal VX-2 carcinoma

To compare survival after local intra-arterial and intravenous administration of doxorubicin, VX-2 carcinoma was implanted in one kidney of 48 rabbits. Treatments were given 9-14 days after tumor implantation. Survival after doxorubicin was significantly longer than the controls, whereas no difference was established between intra-arterial or intravenous treatment. Overall only 9 of 32 doxorubicin-treated rabbits were cured at autopsy after 18 months. It was assumed that circulating tumor cells from tumor implantation resulted in "primary" lung metastases. To kill circulating tumor cells intravenous doxorubicin was given immediately before implantation in 40 rabbits, followed by combinations of nephrectomy and doxorubicin. Doxorubicin without nephrectomy cured 8 of 16 rabbits, whereas doxorubicin combined with nephrectomy cured 4 of 16. Doxorubicin improved survival in responders, but likelihood of response was limited. Nephrectomy did not improve survival, most likely due to metastatic seeding at implantation. Intravenous doxorubicin immediately before did not prevent metastatic spread in connection with tumor implantation.

Tumor-related angiogenesis

In recent years, tumor-related angiogenesis has become an important field of research in oncology. It could be stated that growth of solid tumors is completely dependent on neovascularization to provide the tumor with all required nutrients. Special compounds (tumor angiogenesis factor[s]) are released by tumor cells into the environment to stimulate different types of normal cells to become active for the tumor. In particular, endothelial cells of neighboring capillaries are induced to react. They disintegrate their own basal lamina, detach from their neighbors, enter the extracellular matrix, and migrate toward the tumor mass. Cell divisions occur within such sprouts, thereby increasing the number of migrating endothelial cells. Strands of such cells are formed, and inter- and intracellular lumina develop. Loops of these hollow strands anastomose to form a network of new vessels which become connected with the blood circulation. The tumor mass thus becomes vascularized and can continue to grow. The prevention of neoangiogenesis has an enormous impact on cancer treatment by inhibiting the growth of the tumor. In this review, all important aspects of tumor-related angiogenesis are presented.