Abstract

Bone metastases from renal cell carcinoma (RCC) are not uncommon. The aim of the present study is to determine the correlation between preoperative serum alkaline phosphatase (ALP) levels and bone metastases in patients with RCC.

The records of 109 patients with the diagnosis of histopathologically proven RCC were reviewed. The preoperative ALP values of all patients, bone scans and ALP values of the patients with bone metastases were evaluated. Levels of serum ALP < 270 units per liter (U/L) for male and < 240 U/L for female patients were considered to be normal. Twenty-two patients underwent bone scanning because of bone pain, elevated ALP and/or radiological suspicion of skeletal lesions. Median follow-up was 66 months (range, 3-135).

There were 77 males and 32 females with a median age of 57 years (ranged 26 to 78). Sixty-six patients remained alive, 39 were died of disease and 4 died of other cause at the end of follow-up. The mean and median ALP levels of patients were 148±12.1 U/l (range, 47-1034) and 108 U/l, respectively. The mean ALP levels of patients who underwent surgical treatment were 143±11.4 and 180±15.8 U/l, respectively (p=0.02). The overall incidence of skeletal metastases was 12.8%. Of those, ALP level was in the normal range in 6 (42%) of 14 patients. The ALP levels of patients with and without bone metastases were not statistically different (p=0.18).

These data demonstrate that preoperative ALP levels may be in the normal range even in patients with documented bone metastases based on bone scanning. Therefore we conclude that pre-operative levels of ALP may not guide to diagnose skeletal metastases in RCC patients.