The number of cancer-related deaths in India more than doubled between the years 1990 and 2016, according to a paper titled “The Burden of Cancers and Their Variations Across the States of India: The Global Burden of Disease Study 1990–2016” published in the October 2018 edition of Lancet Oncology.
The paper gives a comprehensive summary of the patterns and time trends of the total cancer burden as well as specific cancer types in each state of India estimated as a part of the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2016. The article was authored by a group called ‘India State-Level Disease Burden Initiative Cancer Collaborators’.
Though there have been previous attempts to review the estimates of cancer incidence and mortality in India and its different regions, the present article presents a comprehensive report of the patterns and time trends.
Methodology of the study
Data from multiple sources, including 42 population-based cancer registries and the national sample registration system of India was used. The study presents data on:
1 The incidence of 28 types of cancer in every state of India from 1990 to 2016
2. Death rates and trends of all types of cancers
3. Disability-adjusted life years (DALYs) for each type of cancer
4. The contribution of major risk factors to the cancer DALYs in India
DALY (Disability Adjusted Life Years)
It is a metric for reporting the disease burden due to mortality and morbidity caused by a disease. It is the measure recommended by the National Health Policy of India for tracking disease burden. Disability for each cancer was estimated by splitting the prevalence into four sequelae: diagnosis and primary treatment, controlled phase, metastatic phase and the terminal phase. Each prevalence sequelae were then multiplied with specific disability weights to see the ‘years lived with disability’ (YLDs). The years of life lost (YLLs) was calculated from the age-specific mortality estimates and the reference life expectancy for that age group. DALYs were computed as the sum of YLLs and YLDs, for each type of cancer for the location, year, age and sex.
The data is reported for 31 geographical units in India, including 29 states, Delhi and union territories other than Delhi.
Summary of the Results: The article states that all cancers together contributed 5.0% of the total DALYs and 8.3% of the total deaths in India in 2016, an increase of 90.9% and 112.8% respectively from 1990. The highest crude cancer DALY rates in 2016 were in the states of Mizoram, Kerala, Assam, Haryana and Meghalaya. The estimated number of incident cancer cases in India increased from 548,000 in 1990 to 1,069,000 in 2016. The crude cancer incidence rate in India increased by 28.2% from 63.4 per 100,000 in 1990 to 81.2 per 100,000 in 2016. The crude cancer incidence rate was the highest in Kerala and Mizoram, followed by Haryana, Delhi, Karnataka, Goa, Himachal Pradesh, Uttarakhand and Assam.
The number of deaths due to cancer in India increased from 382000 in 1990 to 813000 in 2016. The crude cancer death rate in India in 2016 was 61.8 per 100,000, as compared with 44.2 in 1990.
The cancer types responsible for more than 5% of the total cancer DALYs among both sexes combined in 2016 were stomach cancer (9.0%), breast cancer (8.2%), lung cancer (7.5%), lip and oral cavity cancer (7.2%), pharynx cancer other than nasopharynx (6.8%), colon and rectum cancer (5.8%), leukemia (5.2%), and cervical cancer (5.2%). Stomach cancer was responsible for the highest DALYs among all cancers in India in both 1990 and 2016. Among females, breast, cervical, and stomach cancer were responsible for the highest DALYs in 2016. The highest cancer DALYs among males in India in 2016 were lung cancer, followed by lip and oral cavity cancer, other pharynx cancer and stomach cancer.
Among these cancers, the age-standardised incidence rate of breast cancer increased significantly by 40.7% from 1990 to 2016, whereas it decreased for stomach (39.7%), lip and oral cavity cancer (6.4%), cervical cancer (39.7%), oesophageal cancer (31.2%) and leukaemia (16.1%). The study found substantial inter-state heterogeneity in the age-standardised incidence rate of different types of cancers in 2016, with 3.3 times to 11.6 times variation for the four most frequent cancers (lip and oral, breast, lung, and stomach).
Tobacco use, alcohol use and dietary risks were estimated by GBD to contribute to the highest cancer DALYs in 2016: They were responsible for 10.9%, 6.6% and 6.0% of the total cancer DALYs, respectively. Tobacco use was the leading factor.
The authors interpret the study finding by concluding that the data should be used to strengthen the infrastructure and human resources for cancer prevention and control at both the national and state levels. Efforts should focus on the ten cancers contributing the highest DALYs in India, including cancers of the stomach, lung, pharynx other than nasopharynx, colon and rectum, leukaemia, oesophageal, and brain and nervous system, in addition to those of the breast, lip and oral cavity and cervical cancer, which are currently the focus of screening and early detection programmes.