Cancers of the upper alimentary and respiratory tracts in Bombay, India: A study of incidence over two decades

Abstract

Summary Cancers of tongue, oropharynx and larynx in males have registered a decline in incidence over the last two decades in Bombay. This decline has been shown to be a cohort effect. A synoptic measure of risk in each birth cohort, obtained by estimating site-specific cumulative incidence rate over an appropriate age range, was found useful in assessing the risk differential in successive birth cohorts.The changing pattern in incidence of cancers at several sites viz., tongue, oropharynx, and larynx, where bidi smoking is the predominant risk factor, were in conformity with the pattern expected on the basis of changing tobacco habits in the birth cohorts. However, for other sites, viz., hypopharynx, oesophagus and lung, more detailed information on relevant tobacco habits in the birth cohorts is necessary for interpreting the absence of a consistent trend in successive birth cohorts.The recent trends in per capita consumption by type of tobacco (viz., chewing /bidi/cigarette) suggest an emerging cancer pattern in the country at variance with the pattern expected from the current cancer trends in Bombay. Consequently, it is desirable to direct primary cancer prevention programmes especially to cigarette smokers in urban centres and to both bidi and cigarette smokers in the rest of the country.Cancers of the upper alimentary and respiratory tracts constitute almost 50% of all cancers in males in Bombay. These cancers are known to be aetiologically associated with the habit of chewing and smoking tobacco. It is relevant to examine the available data for time trends in incidence of these cancers and to attempt an explanation in the light of the changing pattern of tobacco habits in the population. Subjects and methodsThe Bombay Cancer Registry which was set up in 1964, provides data on chronological trends in incidence of various cancers in the city over a 20 year period (Table I). With a little care in adjusting for differences in classification in the 7th to the 9th revision, of International Classification of Diseases (ICD), the age adjusted rates for various systemic groups could be compared. For specific sites, trends in incidence rates could also be studied in some detail. Furthermore, if the average annual incidences reported for the various periods 1964-66, 1968-72, 1973-77, 1978-82 are considered to represent the incidence at the respective mid points of the given periods, we would have age-specific incidence rates for successive fifth years, viz., 1965, 1970, 1975 and 1980 enabling us to compare the age-specific incidence curves for successive 5 year birth cohorts. For instance, the age-specific rates for 30-34 years in 1964-66, 35-39 in 1968-72, 40-44 years in 1973-77, 45-49 years in 1978-82 could be taken to represent the age-specific incidence rates for 32.5, 37.5, 42.5, and 47.5 years respectively, for those born in 1933, for the purposes of drawing the corresponding age-specific curve.Although the age-specific incidence curves for cohorts indicate the differences between cohorts, the risk dif...

The epidemiology of tongue cancer: a review of global incidence

“…The latest data show an incidence rate of 6.5 per 100 000 per annum from 1988-1992 (Parkin et al, 1997). In a study between 1964, Jayant and Yeole (1987 confirmed that the incidence of tongue cancer in Bombay is falling. Hamada et al (1991) showed that tongue cancer contributed 44.4% of all cancers of the mouth and oropharynx in males in Bombay.…”

“…This converts to 57.0% of all intraoral cancers. The elevated rates in India are commonly linked to betelquid chewing habits, especially if tobacco is a component (Boyle et al, 1990;Daftary et al, 1992;Gupta and Nandakumar, 1999;Jayant and Yeole, 1987;Sankaranarayanan et al, 1989;Smith, 1973Smith, , 1989. In this context, it is also interesting to note that although the rate of tongue cancer in Singapore is low, it is elevated in the Indian sub-population and has been for the past two decades.…”

The epidemiology of mouth cancer: a review of global incidence

“…Once again, tobacco and betel-quid habits are implicated as the primary aetiological agents for the consistently high rates seen in India (Sankaranarayanan, 1990;Daftary et al, 1992), although Sankaranarayanan et al (1989) proposed that other factors (such as immune deficiency, viruses, genetic and dietary factors) are involved in the development of oral cancer in patients under 30 years of age. Some researchers (Jayant and Yeole, 1987;Coleman et al, 1993) have reported a plateauing in the incidence rates of mouth cancer in India from the 1960s to the mid-1980s, but they remain among the highest in the world. In contrast to India, the risk of mouth cancer in Japan is low, but the rate has increased dramatically.…”

Head and neck cancer in India – review of practices for prevention policy

“…buccal mucosa, esophagus, tongue, larynx, hypopharynx and oropharynx. Jayant and Yeole (1987) reported a change in bidi smoking habit in the population of Mumbai, while analyzing the declining trends of cancer of tongue, oropharynx and larynx in men. However, they also suggested an emerging cancer pattern in the country at variance with the pattern expected from the current cancer trends in Mumbai.…”