Tobacco-related cancers and cervical cancers caused most cancer deaths

Cancer killed 5,56,400 people across the country in 2010. The 30-69 age group accounted for 71 per cent (3,95,400) of the deaths. In 2010, cancer alone 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 this age group (30 TO 69 years).

These are some of the findings of a paper published on March 28 in The Lancet. The study found that 7,137 of the 1,22,429 deaths during 2001-2003 were due to cancer, corresponding to 5,56,400 cancer deaths in 2010.

At nearly 23 per cent, oral cancer caused the most number of deaths among 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,” says Professor Prabhat Jha of the Centre for Global Health Research, University of Toronto, who is the senior author of the paper.

Tobacco-related cancers

The most striking find is that tobacco-related cancers accounted for 42 per cent of all male deaths and 18.3 per cent of all female deaths. There were twice as many deaths as a result of oral cancer (due to tobacco chewing), compared with lung cancer.

The percentages translate to a huge mortality number. Nearly “1,20,000 [84,000 in men and 36,000 in women] deaths from tobacco-related cancers were seen in both urban and rural areas,” Professor Jha says. “About 20 per cent was due to chewing of tobacco.”

At 57,000, rural men were twice more likely to die from tobacco-related cancers, compared with their urban counterparts (27,000).

Besides causing specific cancers, smoking contributes to overall deaths from other diseases.

In a February 2008 paper published in The New England Journal of Medicine (NEJM), Prof. Jha and others reported that the total mortality from smoking in India was one million a year.

Bacteria/virus infection caused 19.6 per cent of infection-related cancers — cervical (human papillomavirus- HPV), stomach (Helicobacter pylori) and liver cancers (hepatitis B and C).

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 tobacco and smoking, particularly by men,” says 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 in 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 had about 11.2 per cent chances of dying from cancer before he turned 70. It was 6 per cent in the case of women. Contrast this with the less than 3 per cent risk for men in Bihar, Jharkhand and Odisha.

Tobacco-related cancer 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 northeastern States,” he explains.

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 says. “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 recorded “particularly high rates of these specific cancers.”

Men and women in the nine poorer States (Assam, Bihar, Chhattisgarh, Jharkhand, Madhya Pradesh, Odisha, Rajasthan, Uttarakhand and Uttar Pradesh) had lower risk than the richer States.

Role of education

“Why [this is so] we don't know,” he says about the lower risks in the poorer States. On the whole, literacy had played a big role — mortality rates doubled in the case of illiterates. “Those with secondary and higher education had lower rates of deaths,” he says. In illiterate men the death rate was 106 per 1,00,000; for women it was 107 per 1,00,000. In the educated, the death rates are 46 per 1,00,000 in men and 43 per 1,00,000 in women.

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 Muslims

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 a 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 stresses. “Tobacco is the single most cause of many deaths. Tobacco companies have been beaten in other countries. It is just a matter of time before it happens here.”

“Big tax hike is the answer,” Prof. Jha says 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 adds.

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 highlights.

Changing trends

Trends similar to those in 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, numbers of cervical cancer are dropping in urban areas.

However, the number of breast cancer deaths is increasing. “Big drivers of breast cancer are the changing trends seen in India — late pregnancy and early menarche,” he notes. “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 are collected from a family member.

Though the 2003 figures have been forward projected to 2010, there are lesser chances of gross errors 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.

This article was corrected for a statistical error.

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