Association of Gleason Risk Groups with Metastatic Sites in Prostate Cancer

Abstract

Prostate cancer is the second most common non cutaneous male malignancy worldwide. Gleason composite score is used for risk classification. The most common site of metastasis in prostate cancer is the bone among others. The site and number of metastasis affect overall survival. The ability to predict the metastatic site at diagnosis can assist in predicting the prognosis. To assess the pattern of bone and visceral organ metastases in prostate cancer and evaluate if the initial Gleason grade at diagnosis can predict metastatic sites in prostate cancer. Records of patients with metastatic prostate cancer seen in an institution in Nigeria were analysed. Imaging examination reports used were Technitium99m bone scan for skeletal metastasis, ultrasonography, chest x-ray and cranial CT scan for evidence of visceral metastasis. The association of the initial Gleason grade and site of metastasis was determined using Chi square test for significance. Eighty two patient’s records were analysed. The proportion of patients with low risk Gleason grade (≤6) at diagnosis was 27(32%), Intermediate risk grade (Gleason=7) was 25 (30%) while high risk Gleason grade (8-10) was 30 (38%). Spinal metastasis was 77(94%), pelvis 55(67%) femur 36 (44%) and tibia 1 (1%) while 55(67%) patients had multiple bones affected. Twenty seven patients 33% had visceral metastasis with liver 15(18%) lungs 9 (11%) and brain 3 (4%). There was no significant association between the initial Gleason risk grade with the site of metastasis (x² 3 =2.411, p=0.491). The spine was the most common site of metastases from prostate cancer in this series. The Gleason risk grade at diagnosis was not predictive of metastatic site.

Keywords: Prostate cancer, Gleason grade, metastatic site