Determination of the pattern of bone metastases in breast cancer patients, using radio nuclide imaging

Abstract

Breast cancer is extremely common and frequently involves bone'. Skeletal metastases are shown by bone scintigraphy in 24%of early cases and 84% of advanced cases-. Most lesions are osteolytic but breast carcinoma is also the commonest cause of an osteoblastic metastasis in a woman. Multiple lesions commonly involve the vertebrae, pelvis, ribs and sternum.l'I'he most common metastasizing cancers are those of the breast, lung, kidney, thyroid and prostate>. Bone metastases are found more commonly in middleaged to elderly people but they are uncommon in children.' This was a cross-sectional descriptive study carried out in Medical imaging and therapeutic centre (MITC) Nairobi, between March 2007 and May 2008 to determine the pattern of bone metastases in patients with breast cancer using radionuclide imaging (RNI). A total of 215 patients who had been referred for the purpose of staging or for follow up after treatment were analyzed. The age ranged from 23 yrs to 89 years. The mean age was 55.25 yrs .All except one patient studied were females. The commonest finding was that of multiple metastases to the axial skeleton. The most affected bones were the ribs followed by thoracic spine. Appendicular skeleton was far less affected. The most common symptom of bone metastases was bone pain. However the proportion of patients with bone metastases but with no bone symptoms was found to be high. The patients who had bone pains and metastases were 63.3% while 22.8% had bone pains but no metastases and 36.7 percent patients had no bone pains but had metastases while 77.2 % patients had no bone pains and had no metastases. Patients with bone pain were 5.84.times more likely to have metastasis (p<O.OOl). The study showed that breast cancer mainly affects females and is more common in middle aged and elderly patients. It also demonstrated 99mTc-MDPwhole body scan to be a very effective tool in determining the pattern and distribution of bone metastases in patients with breast cancer 'in all the affected age groups with or without skeletal symptoms. It is therefore of utmost importance that the government is sensitized on the need to increase the number of Gamma cameras in the country to be able to serve a larger population. Besides, the primary healthcare providers should be sensitized on the availability and indications for radionuclide imaging to optimize patient's management. Cooperation between clinicians, radiologist and pathologist is paramount in ensuring high quality of patients care and reducing morbidity and mortality associated with bone metastases.