Bone scintigraphy metastatic patterns in patient with prostate cancer at Ocean Road Cancer Institute.

Abstract

Background: Prostate cancer is the second most common malignancy in the world next to lung cancer and it is the leading cause of morbidity and mortality among men. The most common metastatic site in prostate cancer is the bone. Bone scan has been used frequently to assess metastatic bone disease in prostate cancer patients, the common site of distant metastases being the skeletal system with the pelvis and spine most frequently affected. This study is aiming at finding the pattern of bone metastasis among prostate cancer patients attending ORCI, associated factors for metastases to occur and the frequency of bone metastases among all recruited patients. Broad objective: To determine bone scintigraphy pattern in patients with prostate cancer attending Ocean Road Cancer Institute from June 2014 to June 2016. Methodology: This was a cross section retrospective hospital based descriptive study that was conducted at the nuclear medicine department of the Ocean Road Cancer Institute, Dar es salaam-Tanzania. A total of 139 patients with prostate cancer who were seen from June 2014 to June 2016 at the department for bone scan were included in the study. Whole body scanning was performed 3 h after injection of 700MBq 99mTc methyldiphosphonate. A structured data collection tool was used to record the demographic information, laboratory and histological information from the patients files. Data analysis was done using SPSS version 20. Cross tabulations and Chi square was used for assessing statistical association and comparing proportions respectively. A p-value of less than 0.005 was considered statistically significant. Results: The research included 139 prostate cancer patients who were referred to the nuclear medicine department for bone scintigraphic study. Bone metastases were found in 77 patients (55.4%) The prevalence was higher in the age group between 60 and 79(56.3%) however there was no statistical significance between age and occurrence of bone metastasis [p-0.933] Patient who had PSA level of more than 20 were noted to have higher skeletal metastasis as compared to those with PSA level of 10-20 and those of less than 10ng/ml. [p-0.0001] Gleason score level of more than seven was associated with higher skeletal metastasis as compared to those patients who had Gleason score of 7. The difference was statistically significant [p-0.0001] Spine was the most common site for bone metastasis constituting 72 patients (51.8%) of all the patients followed by ribs metastasis (31.7%), lower limb metastasis (20.1%) and upper limb was the least site for skeletal metastasis (18.7%). Also it was shown that of the spine metastasis, lumbar spine was more frequent affected (48.2%) followed by thoracic and cervical spine (41.0% and 27.3% respectively). The sacrum was the least affected site in the all spine. Conclusion: The prevalence of skeletal metastasis in patients with Ca Prostate attending Ocean Road Cancer Institute was high (55.4%) There was no statistical significant difference between the age group). The prevalence was higher in patients with PSA level more than 20 and those with Gleason score of more than 7. Spine was the commonest site for metastasis and of the spine metastasis lumbar spine metastasis was most frequent site. Recommendation: Bone scintigraphy should be done as baseline in patients with prostate cancer particularly those with PSA level more than 20ng/ml and those with Gleason score of more than 7 and further multicentre study with a larger sample size is recommended.