MUMBAI: American scientists recently stirred a hornet’s nest by linking bad luck
to the occurrence of cancer, but Indian oncologists would rather turn the equation on its head to say that as far as cancer
is concerned, it’s lucky to be in India. Doctors tout two reasons. First, most cancers here are linked to lifestyle and environment
, say doctors, and have little to do with bad luck. It means malignancies could be prevented to an extent. The food we eat, the air we breathe and the choices we make—be it to smoke, drink alcohol or not exercise regularly—are more linked to our chances of getting cancer. “Tobacco is the cause for 40% to 50% of cancers in India as it increases the risk of cancers of the oral cavity, lungs, gastrointestinal tract and urinary bladder,” said Dr S D Banavali who heads medicinal oncology in Tata Memorial Hospital
Second, as Tata Memorial Hospital director Dr Rajendra Badwe says, the rate of cancers in India is very low in comparison to the West. “The incidence of cancer is 90 per 1,00,000 persons in Indian cities and 45 per 1,00,000 in rural India. The West, on the other hand, has a rate of 350 per 1,00,000,’’ he said.
The happy picture does get blurry when one considers that India’s population is so high that even a low cancer rate means a high number of patients. On the eve of World Cancer Day on February 4, the fact is that 10 lakh Indians get diagnosed with cancer every year while seven lakh others succumb to it.
Cancer surgeon Pankaj Chaturvedi said, “By blaming genes, we cannot suppress the fact that the majority of cancers are caused by industry. Tobacco is a big industry, ditto with the fast food industry that is making us obese and thus increasing the risk of cancer.”
Theories about the exact reasons for cancer and why it affects certain people and not others has eluded scientists. Genetic reasons hold true only for around 5% of all cancers. The most heart-wrenching cancers—read pediatric cancers—account for only 3% of the total incidence. Moreover, what about cases in which a woman teacher, who has never smoked or chewed tobacco, gets oral cancer or a young father gets brain cancer? There seems to be no common thread linking all cancers.
In this backdrop, when on January 1, renowned scientists Bert Vogelstein Bert Volgelstein and Christian Tomasetti from Johns Hopkins University in the US mentioned “random bad luck” in their paper on cancer epidemiology, it made headlines across the world. It piqued several experts and the duo, who are reworking their presentation, clarified that “two-thirds of the variations in cancer rates in different tissues could be explained by random bad luck”.
Cancer is a complex disease. Cancer surgeon Dr P Jagannath from Lilavati Hospital, Bandra, said, “Human cells, a trillion of them, keep dividing while fatihfully replicating a complex DNA. While this is a super-precise process, even a ‘cell’ can make errors.” The cell, though, has a remarkable ability to either fix the problem or eliminate the bad gene. “However, some of the changes can occur in critical parts of the DNA, near the oncogenes, which trigger uncontrolled growth and replication of cells that is ‘cancer’,” he added.
The University of Oxford has, since 2011, been studying why cancer rates in India while lower than in the West, are suddenly rising. For instance, incidence of colon cancer is 60 to 70 per l,00,000 in the West, but only five per 1,00,000 in India. “It is our Indian diet (rich in fibre) that has prevented colon cancer,’’ said Dr Badwe.
Indeed, studies in the West, too, have shown that if one stops smoking
, the risk of cancer (as well hypertension and heart disease) reduces. The incidence of lung cancers is different for smokers and non-smokers. The US noticed a drop in breast cancer incidence within two years of banning hormone-replacement therapy.
Some say luck comes into play only among subsets of people: Those who smoke versus those who don’t or those who drink versus those who don’t. “Every smoker doesn't get cancer, but there is a matter of luck in who among the smokers will get cancer,” said Dr Badwe.
Dr Jagannath has another take: “What do we then do about the ‘bad luck’ or the ‘bolt from the blue’ genetic mutation? Very few of them (mutations) are hereditary and can be detected in families that have clusters of cancers like colon or breast cancer but many of them are again ‘random unfortunate events’.”