Tobacco Causes Cancer

Tobacco-related cancers, cervical cancer cause most deaths in India

 
A new study looking at cancer mortality in 2010 in India found a high 71 per cent (3,95,400) deaths in people between 30 and 69 years. Cancer accounted for 8 per cent of the 2·5 million total male deaths and 12 per cent of the 1·6 million total female deaths in the same age group. The high mortality rate during the middle age is very different from the developed countries, where cancer deaths occur during old age.
 
The results are published today (March 28) in The Lancet. The study found that 7,137 of 1,22,429 deaths in 2001-2003 were due to cancer, corresponding to 5,56,400 cancer deaths across the country in 2010.
At nearly 23 per cent, oral cancer caused the most deaths in men. It was followed by stomach cancer (12.6 per cent) and lung cancer (11.4 per cent). In the case of women, cervical cancer was the leading cause (about 17 per cent) followed by breast cancer (10.2 per cent). “All major cancers can be avoided in India,” Prof. Prabhat Jha told this Correspondent over telephone from Delhi. Prof. Jha is from the Centre for Global Health Research, Canada and is the senior author of the paper.
 
Tobacco-related deaths
 
The most striking find is that tobacco-related deaths accounted for 42 per cent of all male cancers and 18.3 per cent of all cancers in women. There were twice as many deaths due to oral cancer (due to tobacco chewing) than lung cancer.
 
The percentages translate to a huge mortality number. Nearly “1,20,000 tobacco-related deaths were seen in both urban and rural areas,” he said. “About 20 per cent was due to chewing tobacco.”
Of the 1,20,000 tobacco-related deaths in 2010, 84,000 were in men and 36,000 in women. At 57,000, rural men were twice more likely to die from tobacco-related mortality compared to their urban counterparts (27,000).
Apart from causing specific cancers, smoking contributes to overall deaths from other diseases as well. In a February 2008 paper in The New England Journal of Medicine (NEJM), Prof. Jha and others found that total mortality from smoking in India was one million a year.
 
Bacteria/virus infection caused 19.6 per cent of infection-related cancers — cervical, stomach and liver cancers.
 
Urban-rural divide
 
Similarity and differences in cancer mortality in men and women were seen in rural and urban populations. For instance, oral cancer was the leading fatal cancer in both rural and urban areas in the case of men. This was followed by lung cancer in urban areas, and stomach cancer in rural areas.
“It is a combination of chewing and smoking, particularly by men,” said Prof. Jha, explaining why oral cancer was the leading cause in urban areas.
 
In the case of women, though mortality from cervical cancer was three times higher in rural areas than urban areas, the rate of cervical cancer deaths was nearly the same in both the areas. Likewise, similar mortality rates were seen in the case of breast cancer in both the areas. But rural women had higher stomach cancer rates compared with urban women.
 
Regional differences
 
A 30-year-old male in northeast has about 11.2 per cent chances of dying of cancer before he turns 70. It is 6 per cent in the case of women. Contrast this with less than 3 per cent risk for men in Bihar, Jharkhand and Odissa.
Tobacco-related deaths in men in Assam and other northeast States were “greater than the national rates of deaths from all cancers.” “Common and long-term use of tobacco is seen in Assam and other northeast States,” Prof. Jha explained.
 
Big variations in cancers not related to tobacco are seen in India. “We have no idea why [this is so]. Further research is required,” he said. “That will be useful for India and the rest of the world.”
In the case of cancers common to both sexes, the variation between States was nearly four times. Northeast States, Kerala, West Bengal and Kashmir than other States recorded “particularly high rates of specific cancers.”
Men and women in the nine poorer States (Assam, Bihar, Chhattisgarh, Jharkhand, Madhya Pradesh, Odissa, Rajasthan, Uttarakhand and Uttar Pradesh) have lower risk than the richer States.
 
Role of education
 
“Why [this is so] we don't know,” he said about the lower risks in the poorer States. But literacy seems to have had a big role — mortality rates doubled in the case of illiterates. “Those with secondary and higher education had lower rates of deaths,” he said. In illiterate men the death rate was 106 per 1,00,000; for women it was 107 per 1,00,000. “Those with secondary and higher education had lower death rates — 46 per 1,00,000 in men and 43 per 1,00,000 in women,” he explained.
 
After taking age into account, the death rates between least and most educated women came out very clearly in “oral cancer followed by stomach and cervical cancers. Rates of breast cancer varied little with education,” the authors highlight.
 
Cancer in Muslim population
 
An interesting find is that in States where Muslim population was higher, cervical cancer risk was “much lower.” For instance, Jammu and Kashmir and Assam, which have 75 and 40 per cent Muslim population respectively, have “less than quarter of the national rates of cervical cancer,” the authors write.
 
As seen internationally, circumcision in men greatly reduces the chances of sexual transmission of HPV virus. Women also had lower incidence of oral cancer. However, breast and stomach cancers were much higher.
Muslim men, however, had higher mortality rates than Hindus in the case of all cancers except liver cancer.
 
Tobacco control
 
“Tobacco control is the best vaccine for lung and oral cancer,” he stressed. “Tobacco is the single most cause of many deaths. Tobacco companies have be beaten in other countries. It is just a matter of time before it happens here.”
 
“Big tax hike is the answer,” Prof. Jha said emphatically. “France tripled the price in ten years and the consumption halved and revenue doubled.” Mexico has increased tax by 30 per cent. “Philippines wants to hike it by 200 per cent. They hope to introduce it next year,” he added.
 
According to him, it is possible to cut many oral, breast and cervical deaths even in rural areas by early detection and treatment. “You don't need super-speciality hospitals in rural areas. Basic services to detect and refer them for treatment is enough,” Prof. Jha underlined.
 
Changing trends
 
Trends similar to developed countries are slowly beginning to emerge. Even though cervical cancer is still the leading cause of cancer deaths in both rural and urban areas, number of cervical cancer is dropping in urban areas. However, the number of breast cancer deaths is increasing. “Big drivers of breast cancer are changing in India — late pregnancy and early menarche,” he noted. “Breast cancer development is similar in rural and urban areas.” But deaths are more in rural areas due to lack of early detection.
 
The data for the study was collected by resorting to verbal autopsy in 2004-2005. In verbal autopsy the details of the cause of death in the family is collected from a family member. Only 7,137 of the total deaths (1,22,429) were due to cancer, and this corresponds to 5,56,400 deaths across the country in 2010.
 
Though the 2003 figures have been forward projected to 2010, there is not much chance of gross error creeping in as nearly 80 per cent of cancer deaths in people older than 15 had a “crude previous diagnosis of cancer by a physician, suggesting some medical confirmation of cancers,” the authors write.
 
Though verbal autopsy cannot provide correct diagnosis of specific cancers where the organs are close to each other, like stomach, misclassification is less likely in the case of oral, cervical and breast cancers.
Since India has only 24 urban population-based cancer registries and just two rural registries, the authors assessed cancer mortality in the Million Death Study (MDS), which is led by the Office of the Registrar General of India. MDS is one of the few large, nationally representative studies of the cause of deaths, including rural areas.
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