Introduction: Primary sarcomas of bone and cartilage (BS) are a group of rare neoplasms, with limitedinformation from Pakistan. The present population-based study was conducted with the objective of examiningdescriptive epidemiological characteristics of BS in Karachi. Materials and methods: Epidemiological data of68 BS registered at Karachi Cancer Registry for Karachi South during 1st January 1995 to 31st December 1997were reviewed.
Results: Forty six (66.7%) cases were diagnosed in males and 23 (33.3%) in females. BS accountedfor 2.2% and 1.1% of all cancers in males and females, respectively. The age standardized rate (ASR) world per100,000 was 1.75 in males and 1.00 in females. Microscopic confirmation was 99.0%. The mean age of male andfemale patients were 26.7 years (SD ±17.4) and 24.3 years (SD ±16.0) respectively. In males 14 (30.4%) BS werediagnosed in the 0-14 year age group and 23 (50.0%) cases in the below 20 years age group. The distribution infemales was 31 (67.4%) and 8 (34.8%) cases, respectively. Approximately half the cases (34.8% males; 47.8%females) were observed in the lower limbs. The most common morphology was osteosarcoma (30.5% males;43.4% females), followed by Ewing’s sarcoma (23.9%) in males and giant cell tumor (13.0%) in females. Agespecificcurves showed a gradual increase in risk from the first until the fifth decade in males, and second tofourth decade in females. The age-specific curves were bimodal. In both genders the first peak was observed at10-14 years but a second peak was observed at 70-74 years in males and 65-69 years in females. The cardinalsymptoms that lead to the diagnosis of bone tumors were pain (22 cases; 32.4%) and spontaneous fractures (45cases; 66.2%).
Conclusion: Karachi falls into a high risk region for BS, which were observed in a relativelyyounger population, with a male predominance and a high frequency of osteosarcoma. The underlying factorsfor BS in Karachi need to be addressed considering the overwhelming proportion of youngsters at risk and thelate presentation.