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In this paper an attempt has been made to study the geographic variations in cancer incidence at various sites, by sex, in Greater Bombay. Crude incidence rates at each site for individual wards have been calculated using the data collected by the Bombay Cancer Registry, for the years 1979 to 1984. To study the variations highest and lowest crude incidence rates in the different wards and the ratio of the highest to the lowest rates for each primary site were calculated. Detailed analyses show that there is a positive relationship between male and female rates for certain sites such as the Buccal Mucosa, Oesophagus, Stomach, Colon, Rectum and Liver. The Tongue, Oropharynx, Hypopharynx, Lung and Larynx present rates that vary widely in males but only slightly in females. Sites such as the Pancreas, Hodgkin's Disease, Lymphoma and Leukaemias do not seem to present any particular pattern. It was interesting to find that those sites where environmental factors are of likely value, such as excessive tobacco chewing and smoking tend to fall in the second category. Particularly striking is the the fact, that habits of etiological value are those to which men are more frequently addicted to than women, probably explaining the low rates in females of the wide variation in male rates.

Reliable data from the Bombay Cancer Registry show an increase in the age-adjusted incidence rate of breast cancer in women from 17.9 to 24.9 per 100,000 population between 1965 and 1985. By fitting a linear regression model based on the logarithm of the breast cancer incidence rates, it was found that the average percentage increases in crude, age-adjusted and truncated rates over this 20-year period were highly significant. Evaluation of these trends in the light of proven etiological factors suggests that the increase in breast cancer incidence is related to a gradual decrease in the proportion of women having a first child before 20 years of age and to an increase in the proportion of "never married" women. These findings were also applicable to the subgroup of Hindus (70% of the population) who show a significant increase in breast cancer over this period as well as a clear cohort effect, the younger birth cohorts in general having higher rates than the 5-year older cohorts. However, the Muslim and Christian subgroups were found to have stable rates. An earlier study of cervical cancer incidence over the same period showed stable rates among Muslims and Christians but a declining trend among Hindus. Breast cancer is now the leading cancer in women in Bombay, while cancer of the cervix uteri predominates in the rest of the country. Well-designed epidemiological studies are urgently needed to explain the phenomenon and to help control the increase in breast cancer before it assumes the magnitude observed in the developed countries.

An attempt has been made to study in depth the cervical cancer problem in Greater Bombay by undertaking epidemiological investigations to identify its aetiology, by utilising the data collected by the Bombay Cancer Registry. Although cancer of the uterine cervix is found to occur at all ages in Bombay, it is mainly seen during middle age. Its incidence is highest in the Hindu community and lowest in the Parsi. This neoplasm appears to have a strong association with the degree of sexual activity. Thus it is rarely seen in nuns , and commonly found in women who have had multiple sexual partners. There is also a relative preponderance in the poorer, uneducated section of the community. In order to identify the high-risk groups, a retrospective study was undertaken of proven cases of cancer of the uterine cervix. The results were compared with those of similar controls, equal in number and closely matched for age, religion, and income, in order to examine the risk factors of possible aetiological importance in women with cervical cancer. We have sought to estimate the effects of parity, the age at first marriage and at first delivery. The highest risk was observed in women who had had multiple pregnancies early in life. It is interesting to note that multiparity seems to be an important risk factor in Bombay women, in contrast to the Western experience.

An attempt has been made in this study to examine the nature and magnitude of the cancer problem in young adults between the ages of 15 and 34 years living in Greater Bombay. The morbidity data utilised for this exercise were obtained from the Bombay Cancer Registry and the mortality analysis was made from the death records maintained by the Bombay Municipal Corporation. In Greater Bombay, the ratio of cancer incidence in this specific group as compared with the total incidence of the disease in the general population was very high in comparison with the Western incidence. The site most commonly affected by cancer in young adults seems to be the lymphatic and haematopoietic tissues in males and breast and cervix in females. The morbidity and mortality rates of the disease in the general population and in children reveal an overall male preponderance, but the situation is found to be totally reversed in young adults. Then again, the incidence as well as the mortality rates appear to decrease with advancing age in children, but in young adults the incidence increases with age. Leukaemia is the most commonly encountered malignancy in the young adult male, followed by cancers of the testes and bones, Hodgkin's disease, and cancers of the brain and connective tissues, in descending order of frequency. In females, breast cancer has the highest incidence followed by cancer of the cervix, leukaemia, and cancers of the ovary and thyroid. When the various registers are ranked according to age-adjusted incidence rates, the figures for Greater Bombay are seen to be at the lowest levels in both sexes.

In this paper an attempt has been made to study the histologic and epidemiologic features of breast cancer in women from various religious groups of Greater Bombay. The crude and age-adjusted incidence rates are seen to be the highest in the Parsi community followed by the Christian, Moslem, and Hindu groups. In all the religious groups, an increase in incidence of breast cancer is first seen in the third decade. This is followed by a sharp increase up to the age of 50-54, leading to a slight drop, and then a consistent but slower rise in the older ages. The high risk of developing this cancer in Parsi women as compared with the Christian, Moslem, and Hindu experience may be due to a higher proportion of Parsi women remaining unmarried, their higher age at marriage, lower age at first pregnancy, broad spacing of pregnancies, and fewer numbers of pregnancies. The distribution according to histologic types of breast cancer in India is characterized by a high frequency of infiltrating duct carcinoma. Medullary, lobular, and squamous cell carcinoma were typical histological varieties of the older age groups, whereas ductal carcinoma was encountered mostly in premenopausal women.

The Sindhis are a Hindu subgroup identified by their place of origin and their written spoken language. These are the people who were originally inhabitants of the Province of Sind, which formed a part of the large Bombay Presidency in Undivided India before 1947. The Sindhi Hindus migrated en masse to India after partition. An attempt has been made here to examine the differences found in the site-specific cancer risks among the Sindhi community, the other Hindu groups (such as the Marathi and Gujrati populations) and the Parsi community of Greater Bombay. As the Indian Census Board does not provide age distribution details for the Sindhis, analysis of the data was undertaken employing frequency ratios. Age-standardized cancer ratios (ASCAR) were also utilized for certain calculations. The common sites of cancer appear to vary greatly between the total Bombay population and the Sindhi group. In Sindhi men, for example, cancers of the lung, large bowel, prostate, kidneys and leukemias are most commmonly seen, whereas laryngeal and oesophageal cancers predominate in the general population of Bombay. In Sindhi women the breast, uterus, ovary, and skin are the preferred sites, whereas cancers of the cervix and leukemias are predominant in the general population of Bombay. It is interesting to note that there is a degree of similarity in the incidence of cancer at certain anatomical sites, such as the prostate, large intestine, and leukemias in males, and breast, cervix, ovary and uterus in females, between the Sindhi and Parsi communities of Greater Bombay.

Differences in habits, customs and ethnic characteristics have provided important leads for the study of cancer in Indian Christians. It is a sign of the times that some of the social customs rigidly upheld by the older generations are rapidly giving way to "Modernism". An attempt has been made to examine the differences found in the site-specific cancer risks in this community in Bombay. An analysis of the data has been made by sex and age-adjusted and age-specific incidence rates. The common sites of cancer were found to vary greatly between the Christian and non-Christian populations of Greater Bombay. In Christian males, the lung appears to be at highest risk, followed by the stomach, oesophagus and larynx, whilst in non-Christian males the oesophagus is the commonest site followed by the lung, larynx and tongue. In females, breast and cervical cancers, which occupy the first and second ranks in Christians reverse their position in non-Christian women.

Population-based incidence rates for cervical cancer in Bombay showed a decline over the past two decades. The observed rates fitted to a log linear regression model showed a good fit. In an attempt to explain the observed decline, cohort-specific age incidence curves were drawn, cumulative incidence rates over common age ranges estimated, and the log linear model fitted separately for each of the religious groups that showed diverse age-adjusted rates for cervical cancer. It was found that the decline could be explained as a cohort effect, indicating that it was due to an upward shift in age at marriage in the younger cohorts. Furthermore, a significant decline was observed in Hindus in whom the mean age at marriage has increased from 12 years in 1921-1931 to about 17 years in the 1960s, but not in the Christians who even in 1911 had a mean age at marriage of 17 years. It appears that, in India, cervical cancer rates will continue to decline until 1995 after which it will stabilise unless there is a change in other risk factors.

Moslems are the followers of Islam who, during the time of the Ghaznavid dynasty of Afghanistan, invaded India for the first time. Islam attaches equal importance to material and spiritual aspects of human life. Men and women have equal cultural rights. Marriage is positively enjoined and vigorously encouraged. Circumcision is compulsory before boys attain the age of 7. More than one wife (up to four) is permitted in Islamic Society. Differences in the habits, customs, and ethnic characteristics have all provided important leads for the study of cancer in this community. It is a sign of the times that some of the religious and social customs that were rigidly upheld by the older generations are rapidly giving way to "Modernism." Hence an attempt has been made to examine the differences found in the site-specific cancer risks in the Moslem community in Bombay. Analysis of the data was undertaken by sex- and age-adjusted and age-specific incidence rates. The common sites of cancer were found to vary greatly between the Moslem and non-Moslem populations of Greater Bombay. In Moslem men, the lung appears to be at highest risk, followed by the larynx, esophagus, tongue, and hypopharynx, whereas in non-Moslem men, the esophagus is the commonest site, followed by the lung, larynx, and tongue. In women, breast and cervix cancers, which rank first and second, respectively, in frequency in Moslems, reverse their positions in non-Moslem women.