Trends and morphology of central nervous system malignancies in Karachi

This study was conducted to assess the patterns of primary central nervous system (CNS) malignancies in Karachi South (KS), a moderate risk population in Asia.

Data for 321 registered cases were reviewed and analyzed in two periods 1995-1997 (111 cases, 75 (67.6%) male (M); 36 (32.4%) female (F)) and 1998-2002 (210 cases, 124 (59.1%) M; 86 (40.9%) F).

Age standardized incidence rate per 100,000, crude incidence rate and relative frequency in 1995-1997 were 3.5, 2.8 and 3.5% (M) and 1.8, 1.6 and 1.7% (F). Corresponding figures for 1998-2002 were 3.3, 2.7 and 2.7% (M) and 3.3, 2.7 and 2.1% (F). Mean age of male and female patients during 1995-1997 was 33.3 years (SD± 20.4) and 30.7 years (SD±19.6). Mean ages for 1998-2002 were 33.2 years (SD±19.5) and 28.7 years (SD±18.5) for males and females respectively. In males, 199 malignancies were reported, 106 (86.9%) cases in the brain, 10 (5.5%) in meninges and 12 (6.0%) in the spinal cord; 122 cases were observed in females, 177 (89%) cases in the brain, 8 (6.6%) each in the meninges and spinal cord. The most common morphology was astrocytoma (72 (36.2%) (M); 40 (32.7%) (F)). Mean age of low grade astrocytoma was 27.8 years (M) and 27.0 years (F); anaplastic astrocytomas, 40.5 years (M), 34.1 years (F) and glioblastoma, 45.7 years (M) and 38.3 years (F). Youngest cases were registered for cerebellum and brain stem.

The incidence of CNS malignancies is stable in males and gradually increasing in females. Astrocytoma is the commonest morphology; they affect a younger age group and show an age gradient in proportion to tumor grade. The mean age varied by sub-site and histology. Focus should be directed towards the understanding the biological nature and risk factors prevalent in this population.