Primary malignancies of bone and cartilage in Karachi

Primary sarcomas of bone and cartilage (BS) are a group of rare neoplasms, with limited information from Pakistan. The present population-based study was conducted with the objective of examining descriptive epidemiological characteristics of BS in Karachi.

Epidemiological data of 68 BS registered at Karachi Cancer Registry for Karachi South during 1st January 1995 to 31st December 1997 were reviewed.

Forty-six (66.7%) cases were diagnosed in males and 23 (33.3%) in females. BS accounted for 2.2% and 1.1% of all cancers in males and females, respectively. The age standardized rate (ASR) world per 100,000 was 1.75 in males and 1.00 in females. Microscopic confirmation was 99.0%. The mean age of male and female patients were 26.7 years (SD-/+17.4) and 24.3 years (SD-/+16.0) respectively. In males 14 (30.4%) BS were diagnosed in the 0-14 year age group and 23 (50.0%) cases in the below 20 years age group. The distribution in females 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. Age-specific curves showed a gradual increase in risk from the first until the fifth decade in males, and second to fourth decade in females. The age-specific curves were bimodal. In both genders the first peak was observed at 10-14 years but a second peak was observed at 70-74 years in males and 65-69 years in females. The cardinal symptoms that led to the diagnosis of bone tumors were pain (22 cases; 32.4%) and spontaneous fractures (45 cases; 66.2%).

Karachi falls into a high risk region for BS, which were observed in a relatively younger population, with a male predominance and a high frequency of osteosarcoma. The underlying factors for BS in Karachi need to be addressed considering the overwhelming proportion of youngsters at risk and the late presentation.