'Breast, lung cancer rising; lifestyle, tobacco consumption, indoor pollution major factors'

Interview / Dr Prashant Mathur, director, ICMR-NCDIR

breast-cancer-reuters Representational image | Reuters

By 2025, India may have 15.7 lakh cancer patients, up from the 13.9 lakhs that are estimated in 2020, according to the latest National Cancer Registry Program (NCRP) report, released recently by the ICMR-National Centre for Disease Informatics and Research (NCDIR). The report, brought out every three years, is based on globally recognised processes of data collection, research and analysis. “The data generated by the NCRP is essentially used to guide policy decisions. For instance, cancer screening programs in the country are based on this data. Our data is also used by the WHO for generating cancer estimates in neighbouring countries,” says Dr Prashant Mathur, director, Bengaluru-based ICMR-NCDIR.

Cancer registries such as the NCRP serve as sentinel surveillance programs—every town, city needn't have a registry, but the ones that exist are representative of the cancer cases in that region. From representing two per cent of India's population in 1982, to the current 10 per cent coverage, Mathur says that the country's cancer registry program has come a long way. The data is revealing—over half of cancers (50-60 percent) in India such as those due to tobacco and alcohol consumption, and infections can be prevented, says Mathur. Cancers of the breast and lung are rising, while cervical and stomach cancers are declining, he adds.

Excerpts from an interview on trends from the latest report, and the temporary impact of COVID-19 on cancer data collection:

How representative is the data given that the cancer registries are located in a few areas in the country?

The National Cancer Registry Program (NCRP) was established by ICMR in 1982 with a few registries at select places. Since then, the network has increased to the current size of 272 registry sites spread across the country. The 36 population based cancer registries (PBCR) collect data among all age groups and gender. These are people residing there for at least a year before the diagnosis of cancer. Besides, the 236 hospital-based cancer registries (HBCR) also collect cancer data; these are hospitals wherein patients come in from any part of the country for treatment. Together, the PBCR and HBCR provide information on new cases of cancers diagnosed yearly, burden of cancer, trends, clinical management, outcomes and survival. 

The national cancer registry program is meant to capture high quality data to guide cancer-related policy and program implementation, as is done in many other countries. In the NCRP report 2020, the PBCRs covered 100 million average annual person-years, which accounts for close to 10 per cent of India's population. The registry data is fairly representative at national and regional levels based on statistical calculations. For state-based estimates, though, having  more registry sites will be useful. 

What are the significant new trends, and the ones that have been consistent through the years? 

Trends are unlikely to change very soon. But the direction of movement is important to note. For the first time, time trends in cancer rates analysis is done for 16 PBCRs with long duration data. 

A rise in the incidence of all kinds of cancer was observed in a majority of the population-based registries. There was a significant decrease in incidence of cancer in few registries (Imphal west, Mumbai, Sikkim state and Dibrugarh district) among males. A decrease in the incidence rate of cervical cancer among women in 10 population-based registries—except in Mizoram, Aurangabad and Sikkim PBCRs where it is still on the rise—was also noticed.

However, there was a significant increase in the incidence of breast cancer in women across all sites, over the years. Also, we observed an increase in the incidence rates of lung cancer in Kamrup urban, Chennai, Delhi and Bangalore registries among both men and women. Five population-based registries showed an increase in incidence rates among men, while for women, it was seen in 11 population registries.

Among both genders, there was a significant increase in the incidence rates of stomach cancer in Kamrup urban. Mizoram, Mumbai and Chennai registry saw a significant decrease in the incidence of stomach cancer among men and women.

Cancer of the oesophagus and brain has been stable over a period of time. Besides, tobacco-related cancers continue to contribute to a large proportion of cancers (27.1 per cent of all cancers).

perprashant-mathurson Dr Prashant Mathur

Cancer trends in the north-east have been prevalent for a while now. To what factors can these be attributed to? 

Cancer rates from the north-eastern states have been on the higher side as compared to other parts of the country. The leading sites of cancer in the north-east region were nasopharynx, hypopharynx, esophagus, stomach, liver, gallbladder, larynx, lung, breast and cervix uteri.

Cancers are driven by a complex interaction of many known modifiable risk factors, as well as genetic susceptibility, age and gender. Most important, though, are the tobacco-related cancers due to its high consumption in all forms. Other factors such as alcohol use, inappropriate diet, physical inactivity, air pollution (especially indoor air pollution due to the use of solid fuels), certain infections (Human papilloma virus, hepatitis B and C, H.pylori, human immunodeficiency virus (HIV), salmonella) also contribute to the cancer burden.

Inadequate cancer treatment facilities and their accessibility ineach state leads to an enormous burden of seeking treatment outside, out of pocket expenditure, delayed diagnosis and initiation of treatment.

When it comes to childhood cancers, what are the significant trends? Delhi has the highest rates, how do we understand that? 

A trend analysis of childhood cancer has not been done. However, for the past few years, we are recording high rates of overall childhood cancers in Delhi and other metro cities. Appropriate research is needed to explain these observations in terms of early life exposure to carcinogens, access to diagnostic and treatment facilities   and awareness. 

What are the gaps that remain in data collection in cancer? What are the challenges that we need to tackle in the coming year, given the current health crisis?

As cancer is not a notifiable disease in India, data collection is by active pursuit and is dependent on co-operation of various hospitals that treat patients of cancers. Several states do not have any PBCR yet—Rajasthan, Odisha, Himachal Pradesh, Andhra Pradesh, Jharkhand, Haryana, Goa—which hampers state-level estimations. We need more representation of rural data in order to monitor trends related to urbanization, changing lifestyles and migration etc. A desirable step will be sharing of relevant cancer data from other sources, which will help in improving the quality of data, reducing active pursuit and thus completing the cancer registry database. The present health crisis is likely to impact hospital attendance of cancer patients and thus, of data availability. Follow ups for outcome would require use of technology and remote access healthcare.