Management and prognostic significance of hypercalcemia in renal cell carcinoma

A retrospective study was conducted to evaluate the prognostic significance of hypercalcemia associated with renal cell carcinoma and the efficacy of different treatment modalities. Twenty-seven of 160 (16.8%) patients with renal cell carcinoma were found to have tumor-induced hypercalcemia: 24 had Stage IV disease, 1 Stage III disease, and 2 Stage I disease. There was no evidence of bone metastasis in 13 of 27 (48%) patients. A total of 89 episodes of acute hypercalcemia were treated: 36 episodes resulted in a complete response ([CR] calcium levels returning to normal), 24 partial response ([PR] calcium decrease greater than 1 mg/dL, but above normal) and 29 negligible response ([NR] calcium decrease less than 1 mg/dL) to treatment modalities used. One patient with Stage I disease and 3 with Stage IV disease underwent nephrectomies resulting in 2 CR and 1 PR. There was a complete response (CR) to mithramycin in 7 of 10 (70%) acute hypercalcemic episodes, to furosemide and mithramycin in 12 of 20 (60%), to steroids or furosemide and steroids in 3 of 7 (43%), to hydration in 4 of 13 (31%), and to furosemide in 7 of 25 (28%). The response rates to phosphates, indomethacin, and calcitonin were low but involved a small number of patients. Survival in 24 patients with Stage IV disease was 5-239 days (av 87.3 days). There was essentially no survival difference between patients who had an initial calcium elevation less than or greater than 13 mg/dL. We conclude that mithramycin is more effective in controlling acute hypercalcemia secondary to renal cell carcinoma than furosemide or hydration. Steroids appear to be effective but our experience was limited. Surprisingly, the degree of calcium elevation did not show a significant correlation with survival.