Penang cancer cases reported to the National Cancer Registry of Malaysia, 1987-1990: an epidemiological analysis.

2,124 cases of cancer diagnosed and/or treated in Penang between 1987-1990 were reported to the National Cancer Registry of Malaysia by hospitals in Penang. 1,762 met the criteria for Penang incident cases first diagnosed between 1987-1990, and were the subjects on which all subsequent analyses were based. 85 per cent of case notifications were from Mount Miriam Hospital. Among males, all-site cancer incidence rates (age-standardised) were highest among Chinese, and lowest among Malays. Among females, the Indian female incidence rate was highest, higher than that of any other ethnic-gender sub-group. Site-specific cancer rates varied according to ethnicity and gender, but overall the four most frequent cancers reported from Penang were breast, lung, cervix and nasopharynx cancers. It needs to be emphasised that all these results are highly tentative since they are based on notified cancer occurrences and hence are very uncertain proxies for true cancer incidence. Based on incidence rates from the Singapore Cancer Registry (1978-1982), the expected number of incident cases in 1989 for Penang (Malays, Chinese and Indians combined) was 1,561. The number notified to the National Cancer Registry was 496. This underlines the tentative nature of this analysis of the returns for 1987-1990 from Penang.