Clinical significance of pulmonary metastases in stage D₂ prostate cancer patients

Several prognostic factors such as the extent of bone metastases (EOD) in advanced prostate cancer (PCa) have been reported. Metastasis of the lung is rarely a significant clinical factor in the management of prostate cancer. The present study evaluates the clinical significance of lung metastases. We retrospectively reviewed the PCa database to identify patients with pulmonary metastases at initial diagnosis. The medical records of the patients were examined with respect to age, histologic grade, EOD score, marker response to endocrine therapy and clinical outcome. We then compared several potential clinical factors between patients with and without pulmonary metastases. Next, we retrospectively reviewed autopsy records of 60 Japanese patients who died of hormone-refractory metastatic PCa with particular focus upon metastatic profiles. A comparative study of stage D₂ patients with (n = 20) and without (n = 77) pulmonary metastases found no significant differences in EOD score, performance status, marker response and survival. Only tumor grade was better in the group with, than without pulmonary metastases (P = 0.0120, chi-square analysis). In the series of autopsies, we found pulmonary metastases in 38 cases (63%), following metastases of the bone (57 cases, 95%) and lymph nodes (52 cases, 87%). A retrospective analysis of survival showed that patients with bone or lymph node metastases had a positive relative risk. In contrast, lung metastasis could be a positive prognostic indicator, although the findings were not statistically significant. These data suggest that the presence of pulmonary metastasis has no ominous impact on clinical course and disease outcome even in patients with disseminated prostate cancer.