Pattern and distribution of distant metastases in anaplastic prostate carcinoma: A single-institute experience with 101 patients

OBJECTIVE. The aim of this study was to evaluate the sites and frequencies of distant metastases in patients with anaplastic prostate carcinoma and to correlate those findings with prostate-specific antigen (PSA) levels. MATERIALS AND METHODS. Patients with anaplastic prostate carcinoma (n = 101) underwent CT and bone scans before platinum-based chemotherapy. CT findings were retrospectively reviewed to identify the sites of metastases. CT findings were correlated with baseline PSA levels. The Wilcoxon rank sum test was used to correlate PSA levels between patients with metastases at osseous and nonosseous sites. The Wilcoxon rank sum test was also used to correlate the type of bone metastases (blastic vs lytic) and the PSA levels. RESULTS. Eighty-three of 101 patients (82%) had osseous metastases. PSA levels were significantly higher in patients with bone metastases than in patients without osseous metastases. However, 23 of the 83 patients (28%) with bone metastases had PSA levels in the normal range (i.e., < 4 ng/mL). The type of bone metastases (blastic vs lytic) did not show any statistically significant correlation to the PSA levels. Overall, 63 of 101 patients (62%) had nonosseous distant metastases at one or more sites, including the liver (n = 34), lung (n = 24), mediastinum (n = 31), pleura (n = 7), brain (n = 9), adrenal glands (n = 6), peritoneum (n = 4), and spleen (n = 1). PSA levels were not significantly elevated in patients with nonosseous distant metastases. Twenty-six of the 63 patients (41%) with nonosseous metastases had PSA levels in the normal range (< 4 ng/mL). CONCLUSION. Patients with the anaplastic clinical variant of prostate cancer have a high frequency of typical and atypical sites of metastases. Common sites of nonosseous distant metastases include the liver, lung, mediastinum, pleura, brain, and adrenal glands. PSA levels are unreliable and may be disproportionately low, despite the presence of multifocal large-volume metastases. CT of the chest, abdomen, and pelvis should be considered in routine staging and follow-up of patients with anaplastic prostate carcinoma regardless of their PSA levels.