Lack of correlation between prostate-specific antigen and the presence of measurable soft tissue metastases in hormone-refractory prostate cancer

Appropriate staging procedures for patients with hormone-refractory prostate cancer are poorly defined. In particular, there are no studies correlating prostate-specific antigen (PSA) with more traditional methods of staging. We have evaluated the abdominal/pelvic CT scan, bone scan, and PSA results following initial diagnosis of hormone-refractory prostate cancer in 177 consecutive patients (median age = 63.1 years, range 45-80). Thirty-four patients (19.2%) had measurable lesions (≤2 cm) on CT scan compatible with metastatic disease. Of the patients with measurable lesions, 29/34 (85.3%) had retroperitoneal and/or pelvic adenopathy; 5 patients (14.7%) had measurable lesions in the liver. Other sites of metastatic disease were detected in less than 1% of the patients receiving scans. All patients had bone scan abnormalities compatible with metastatic disease. Results of these imaging studies were then compared to PSA serum concentration (Abbott IMx). The mean PSA concentration was not different in those patients with soft tissue disease as compared to those without soft tissue involvement and there was no correlation between PSA concentration and the presence or absence of measurable soft tissue disease. In contrast to previously published studies in hormone-naive prostate cancer patients, these studies in hormone-refractory patients indicate that the detection of metastatic disease by standard radiological procedures cannot be predicted by measurement of serum PSA.