Objective: Our objective was to use functional CT to evaluate the effects of thalidomide in patients with metastatic renal cell carcinoma.
Subjects and methods: Patients with proven metastatic renal cell carcinoma were examined prospectively with functional CT. Functional CT studies (cine mode, 4 x 5 mm) were performed through the tumor after i.v. administration of a bolus of contrast material before and every 12 weeks after treatment with thalidomide. Quantitative values for blood flow, blood volume, mean transit time, and permeability-surface area product were calculated with commercial software. The average difference in percentage change in functional CT parameters from pretreatment to 12 and 24 weeks after treatment and the median difference in percentage change in functional CT parameters between response groups were assessed. We also tested whether percentage changes in functional CT parameters 12 weeks after treatment correlated with time to progression of disease and size of the perfused lesion.
Results: Sixteen patients with a total of 23 tumors underwent at least one follow-up functional CT examination. Blood flow, blood volume, and permeability-surface area product decreased significantly 12 weeks (-18%, p = 0.0039; -15%, p = 0.0350; -24%, p = 0.0010) and 24 weeks (-28%, p = 0.017; -19%, p = 0.0300; -25%, p = 0.0031) after treatment with thalidomide. Time to progression correlated significantly with percentage change in blood flow (r = -0.34; p = 0.040) and permeability-surface area product (r = -0.36, p = 0.023) at 12 weeks. Responders had a significantly larger decrease in blood flow 12 weeks after treatment than did nonresponders (-29% vs -6%; p = 0.032). We also found a significant correlation between decrease in size of the perfused lesion and percentage decrease in blood flow 12 weeks after treatment (r = 0.50; p = 0.019).
Conclusion: Changes in functional CT parameters 12 weeks after treatment may be useful for monitoring the effects of thalidomide and predicting treatment outcome among patients with metastatic renal cell carcinoma. Further study with a larger clinical trial is needed.