Cancer incidence in Indians from three areas: Delhi and Mumbai, India, and British Columbia, Canada.

BACKGROUND: Studies of immigrants have provided unique opportunities for examining disparities in cancer screening and the impact of lifestyles and environmental exposures on cancer risk. Findings have been useful for planning cancer control strategies and generating etiological hypotheses. Although India is a leading source of immigration to British Columbia (BC), Canada, little is known about the cancer profiles of Indo-Canadians, information needed for planning health services and health promotion initiatives for this population. METHODS: Using data from three population-based cancer registries, cancer incidence was compared for four population groups (in each of Delhi and Mumbai, India; Indo-Canadians in BC, Canada; and the BC general population) over three time periods (1976-1985, 1986-1995 and 1996-2003). BC Indo-Canadians were identified by using Indian surnames. RESULTS: Age-standardized incidence rates (ASRs) for all cancers combined were lowest for men and women in Delhi and Mumbai, intermediate for BC Indo-Canadians, and highest for the BC general population. Ranking of common cancer sites and ASRs for Indo-Canadian men and women more closely resembled those for the BC general population, rather than those for either Delhi or Mumbai. ASRs and rankings of common cancer sites are presented by gender for the four population groups. CONCLUSIONS: Cancer incidence patterns in BC Indo-Canadian men and women differed from those in India, being more similar to the BC general population.

Population-based survival from cancers of breast, cervix and ovary in women in Mumbai, India.

BACKGROUND: Breast, cervix and ovarian cancers contribute more than 45% of the total in women in Mumbai and survival proportions for these neoplasms are very high in most developed populations in the World. The authors here report and discuss the population-based survival for these cancers in Mumbai, India. METHODS: Follow-up information on 4865 cancers of breast, cervix and ovary, registered in the Mumbai Population Based Cancer Registry for the period 1992-1994 was obtained by a variety of methods, including matching with death certificates from the Mumbai vital statistics registration system, postal/telephone enquiries, home visits and scrutiny of medical records. The survival for each case was determined as the duration between the date of diagnosis and date of death, date of loss to follow-up or the closing date of the study (December 31(st), 1999). Cumulative observed and relative survival was calculated by the Hakulinen Method. For comparison of results with other populations, age-standardized relative survival (ASRS) was calculated by directly standardizing age specific relative survival to the specific age distributions of the estimated global incidence of major cancers in 1985. The log rank test was used in univariate analysis to identify the potentially important prognostic variables. The variables showing statistical significance in univariate analysis were introduced stepwise into a Cox Regression model to identify the independent predictors of survival. RESULTS: The 5-year relative survival rates were 46.2% for breast, 47.7% for the cervix and 25.4% for the ovary. Higher survival was observed for those younger than 35 years for all these three sites. For each, survival declined with advancing age. Single patients who remained unmarried had better survival. For all sites Muslims had a better and Christians a lower survival as compared to Hindus. Education did not appear to be of significance. Survival decreased rapidly with advancing clinical extent of disease for all sites. With localized cancer, 5-year rates ranged from 54.7% to 69.3%, for regional spread 20.4% to 41.6% and distant metastasis not a single site recorded more than 5%. On multivariate analysis, age and extent of disease emerged as independent predictors of survival for all the sites. CONCLUSION: All the sites included in the study demonstrated moderate survival rates with significant variation. Comparison with other populations revealed lower survival rates as compared to developed countries, particularly for breast and ovary. In Indian populations survival proportions did not show much variation for these cancers. Early detection and treatment are clearly important factors to reduce the mortality from these cancers.

Population-based survival from cancers having a poor prognosis in Mumbai (Bombay), India.

BACKGROUND: Oesophagus, stomach, pancreas and lung cancers contribute more than 35% of the total cancer incidence in Mumbai and survival rates for these cancers are very poor in most populations in the world. The authors here report and discuss the population-based survival from these cancers in Mumbai, India. METHODS: Follow-up information on 5717 cancers patients having a low prognosis, registered in the Mumbai Population-Based Cancer Registry for the period 1987-1991, was obtained by a variety of methods, including matching with death certificates from the Mumbai vital statistics registration system, postal/telephone enquiries, home visits and scrutiny of medical records. The survival for each case was determined as the duration between the date of diagnosis and date of death, loss to follow-up or the closing date of the study at the end of 1996. Cumulative observed and relative survival rates were calculated by the Hakulinen Method. For comparison of results with other populations, age-standardized relative survival (ASRS) was calculated by directly standardizing age specific relative survival to the specific age distributions of the estimated global incidence of major cancers in 1985. The log rank test was used with univariate analysis to identify the potentially important prognostic variables. The variables showing statistical significance in univariate analysis were introduced stepwise into a Cox Regression model to identify the independent predictors of survival. RESULTS: The 5-year relative survival rates were 11.8% for oesophagus, 10.1% for the stomach, 4.1% for the pancreas, and 7.0% for lung. Females had higher survival rates than males, except with lung cancer. Lower survival was observed for those younger than 35 years for all 4 sites. For each site, survival declined with advancing age. Single patients who remained unmarried had better survival, except with pancreatic cancer. For all sites Muslims had a better survival and Christians had a lower survival as compared to Hindus. Education did not show any pattern for any site. Survival decreased rapidly with advancing clinical extent of disease for all sites. Survival for localized cancer ranged from 12.5% to 31.3%, for regional spread 1.3% to 3.4% and with distant metastasis not a single site recorded more than 1%. On multivariate analysis, extent of disease emerged as an independent predictor of survival with all the sites. Also, age for oesophagus, stomach and lung, religion for oesophagus and stomach, and education for stomach and lung, emerged as independent predictors of survival. CONCLUSION: All the sites included in the study demonstrated very low survival rates with significant variation. Comparison with other populations revealed lower survival rates than for Shanghai-China. In remaining populations, survival proportions did not show much variation for pancreas and lung cancers. For stomach cancer, European countries showed better survival rates. Early detection with treatment is clearly important to reduce the mortality from these cancers.

Cancer in Women in Mumbai, India.

The challenge of population based cancer registration in developing countries is enormous. In India, the first Population Based Cancer Registry named "Bombay Cancer Registry" was established by the Indian Cancer Society in Mumbai (formerly Bombay) in 1963, covering the population of the Mumbai Agglomeration. Up to now this registry has collected epidemiological information on more than 200,000 cancer incidence cases and 100,000 cancer deaths. At present this registry covers an area of 603.00 sq.kms having a population of 12 million. Here, an attempt has been made to analyse and interpret cancer incidence and mortality data for women, registered in Mumbai during 1993-97.

Retinoblastoma: An Epidemiological Appraisal with Reference to a Population in Mumbai, India.

Reliable data on incidence and mortalityfor childhood cancers are available from only a few areas in the developing countries. Neoplasia in children is rare as compared with adult cancer. In Europe, North America and Australia, retinoblastomas account for 2-4 percent of the total and the relative frequency is similar in Asia. In contrast, in African countries retinoblastomas account for 10 to 15% of cancers in children. The data collected at Bombay Cancer Registry for the latest 13 years, 1986-1998, were used for the present study. Analyses were carried out on retinoblastomas by sex, age, religion and laterality, based on differences in rates and proportions. In Mumbai, during the 13-year period in question, there were only 211 cases of malignant tumors of the eyes. Of these, 147 were retinoblastomas, 84 in males and 63 in females, with crude incidence rates per million population of 4.0 and 3.1, respectively. The corresponding age adjusted incidence rates per million population were 4.2 and 3.3. The crude values were found to be higher in Muslims as compared to Hindus and other religious groups, in both sexes. Out of the total retinoblastomas, 105 were localized, 24 demonstrated regional spread and 16 had metastasized or were very advanced. Some 23 patients had bilateral disease. In a total of 60 patients, retinoblastomas developed on the right side and in 58 in the left eye. The highest annual age standardized incidence rates for retinoblastomas, in excess of 7 per million population have been observed in the Fortaleza area of Brazil, Nigeria (Ibadan) and Uganda-Kampala. Retinoblastomas have the lowest median age of all childhood malignancies, approximately 15 months. The male to female ratio generally fluctuates around unity but our data indicated a higher proportion in males. Ethnic differences in the frequencies of unilateral and bilateral retinoblastomas are apparent. There is little evidence that any significant change in the incidence of retinoblastoma over time has occurred in any part of the world. Knudson proposed a 2-mutation hypothesis to explain the occurrence of retinoblastoma in both hereditary and sporadic forms with differing frequencies of bilaterality, and this model has become a paradigm for considering the role of genetic factors in the etiology of cancer in general.

An Assessment of Cancer Incidence Patterns in Parsi and Non Parsi Populations, Greater Mumbai.

The Mumbai Cancer Registry has been in operation since 1964 and reliable morbidity and mortality data on cancer have been obtained for the first time in India, from a precisely outlined population. An attempt has been made to examine the differences noticed in the site-specific cancer risk, between two groups of people living in this area-the Parsi and non Parsi population of Mumbai. For this study, data has been utilized, collected by Mumbai Cancer Registry for the latest five years. For comparison between Parsi and non Parsi populations, crude and age-adjusted rates have been used. The overall age-adjusted rates for the Parsi's were found to be lower than those for the non Parsi populations and more noticeably their site-specific risks seem to differ radically from the non Parsi pattern. Cancers of the buccal cavity, pharynx, larynx, oesophagus and cervix uteri which are frequently seen in the non Parsi population, are less commonly observed in the Parsi community. On the other hand the Parsi rates are higher at site such as the female breast, endometrium, lymphomas and leukaemias. The observed site-specific contrast are believed to be due to differences present in the habits, customs and economic status of the two groups.

An Assessment of Improvement in Reliability and Completeness of Mumbai Cancer Registry Data from 1964-1997.

The Mumbai Cancer Registry was established in 1964 with the aim of obtaining reliable morbidity and mortality data from precisely defined urban population. It was first and only such registry for merely two decades functioning in the country. Up to now more than 200,000 cancer cases are registered and with over 100,000 cancer deaths are recorded in data files. For studying improvements in the Mumbai Cancer Registry data, the data published in consecutive seven volumes (Vol.-II to Vol.-VIII) of "Cancer Incidence of Five Continents published by International Agency on Research on Cancer", Lyon, France have been used. For studying completeness of the data, the indicators 'Proportion of Deaths in Period'; 'Proportion of Death Certificates only' and stability of age incidence rates have been utilized. The indicators 'Proportion of cases registered on histological verification', 'The proportion of cases where age is not known', 'The flattening of age incidence curve' and 'Proportion of other and unspecified neoplasms can throw some light on the quality of data collected by the registry. There has been notable improvement in percentages of histological verification cases and substantial decrease in the proportion of death certificate alone cases in both the sexes over a period of time. Mortality Incidence ratio remained stable over a period of time in both the sexes. The proportion of cases where age is not known never exceeded 0.020% in either sex, for any site, for any period. The proportion of cases registered as other and unspecified sites, initially was around 8 to 9% then it has been dropped down to 5%. The crude incidence rates for all sites together are stable throughout the period of observation in both the sexes while age adjusted incidence rates show declining trend in both the sexes. There is no change in the pattern of age-specific incidence curves over a period of time in both the sexes. On examining various indices of reliability and completeness of Mumbai cancer registry data it can be concluded that, the data collected by this registry is quiet complete and reliable. While applying various checks for validity for a period from 1964-66 to 1993-97, it indicates that there is quiet improvement in almost all indices over a period of time in Mumbai cancer registry data.