Primary Malignant Bone Tumours at the University Teaching Hospital in Lusaka Zambia

Abstract

Introduction: Primary malignant bone tumours include malignancies arising primarily from bone tissue. This is opposed to secondary bone tumours in which case the neoplastic elements arise primarily from other sites within the body and secondarily spread to bone. Primary malignant bone tumours are generally  considered rare. Wherever primary malignant bone tumours occur they tend to pose serious challenges in terms of diagnosis, management and morbidity and mortality. However there is a lack of organised local information demonstrating the burden of disease resulting from these tumours.
Objectives: The main objective of this study was to establish the pattern of primary malignant bone tumour distribution at the UTH. The specific objectives of the study included to: Outline of the socio-demographic characteristics of patients,  determining the frequency of primary malignant bone tumours at UTH and the  hospital prevalence of primary malignant bone tumours including their histological distribution and the clinical presentation.
Materials and Methods: A retrospective cross-sectional survey of patients who presented to The University Teaching Hospital (UTH), Lusaka, Zambia with histologically confirmed primary malignant bone tumours was conducted for the period from the 1st of January 2008 to the 31st of December 2012.
Results: There were a total of hundred and fifty three (153) patients seen in total. Sixty six (43%) were females while 87 (57%) were males. The age range was 3yrs to 78yrs. The mean age was 31.6 yrs. Sixty nine percent (69%) of the patients were aged 40 years and below. The age distribution of primary malignant bone tumours showed a bimodal pattern of distribution with peaks in the second and sixth decades of life. The majority (35%) of the patients reported Lusaka Province as their  domicile, while the least (2.0%) hailed from North Western Province. The highest number of patients, 39 (25.5%) was recorded in 2012 and the lowest number 20 (13%) was recorded in 2011. Based on National Cancer Registry data, from 2008 to 2011, the overall proportion of patients with primary malignant bone tumours compared to all the other cancers recorded at UTH ranged between 1.7 to 2.8%. The majority, 84 (55.3%), of the patients had osteosarcoma, followed, in descending order, by multiple myeloma 42 (27.6%), chondrosarcoma 11 (7.2%), Ewing’s sarcoma 8 (5.3%), fibrosarcoma 3 (2.0%) and lymphoma 2 (1.3%). The majority of patients (35.5%) reported pain and swelling alone as a presenting complaint while 19.8% of the patients presented with pathological fractures. The single and most commonly reported anatomical site was from multiple myeloma which has a general skeletal involvement (27%); the second most commonly involved site was the  femur 23.7%, followed by the tibia 17.1%, and the humerus 7.5%.
Conclusion: Notwithstanding the inconclusive nature of the information on geographic distribution of tumours, the findings in the study paralleled those reported in literature.

Key words: Malignant Bone Tumour, Bone Neoplasms, Zambia.