Rising Incidence of Gastric Malignancies in Karachi, 1995- 2002


Introduction: South Asia is an enigma for gastric cancer, a low risk region with a contradictory high prevalencefor Helicobacter pylori. Patients and
Methods: To examine the demographics, pathology and trends of gastriccancer in Pakistan, epidemiological data of 335 gastric malignancies, registered at Karachi Cancer Registry(KCR) for Karachi South (KS), during 1st January 1995 to 31st December 2002 were reviewed. Trends werestudied by categorizing the cases into two time periods ‘1995-7’ and 1998-2002’.
Results: Ninety six cases ofgastric cancers were registered in the 1995-7 period, 61 in males and 35 in females. In males, the ASR (world),and crude incidence rate (CIR) per 100,000 were 3.9 and 2.3 respectively. In females, the values were 3.0 and 1.5.In the 1998-02 period 239 cases of gastric cancer were registered, 156 cases in males and 83 in females. The ASRand CIR per 100,000 were 6.0 and 3.4 in males and 3.6 and 2.1 in females. An 18% increase was observed inmales and 14% in females during the seven year study period. The male to female ratio was 2:1.The mean age ofmale patients was 51.9 years [95% CI 45.8; 58.1; SD ±17.9] in 1995-7 and 53.7 years [(95% CI 51.6; 55.9; SD±14.0] in 1998-02. In females the mean age for the two periods was 48.8 years (95% CI 42.5; 55.0; SD ±18.2] and48.4 years [95% CI 45.4; 51.5; SD ±13.9] respectively. Age-specific curves showed a gradual increase in riskfrom the second until the seventh decade. The majority of the cases presented as poorly or moderatelydifferentiated distal (non-cardia) cancers with a regional spread.
Conclusion: Gastric cancers in Karachi fallinto the prototype of a low risk developing country pattern. The incidence is increasing, most marked in malesabove 40 years of age. Larger pathology-based studies are required to comment on the precise morphologicalsub-types of gastric adenocarcinoma. Etiological studies focused on different strains of H. pylori are required toaddress the gastric cancer enigma, whilst examining possible protective environmental or genetic factors.