The key to combating lung cancer is the development of novel immunotherapies and diagnostic techniques and not a complete ban on tobacco that is impossible to enforce, says American Nobel laureate Harold Varmus.
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Varmus won the 1989 Nobel Prize in Medicine— along with American immunologist Michael Bishop—for the discovery of gene mutations that can lead to the transformation of a normal cell into a tumour cell and result in cancer.
Dwelling at length on lung cancer, the leading cause of death due to cancer globally as well as in India, Varmus said, "Trying to prohibit tobacco or to ban tobacco entirely is a mistake because we know that you can't enforce complete prohibition. That is the kind of thing that leads to various forms of crime and it doesn't work."
"I don't think bans work very well. But I do think that not just in India and every country, including the US, where we still have 18% of our population smoking, we have people using nicotine vapes instead of cigarettes. All these are risk factors for cancer," the scientist told PTI in an interview at Ashoka University in Sonepat, Haryana.
The Parliamentary Standing Committee on Health and Family Welfare in India has recommended in its latest report that the government ban the sale of loose cigarettes.
“The focus should be on novel therapies and diagnostic techniques and not on complete prohibition,” the 83-year-old said when asked if tobacco ban is the answer to combat the deadly disease.
Noting that there were limited therapies available for lung cancer 20 years ago, Varmus said he is "optimistic" about developments in the field of cancer research.
"Broadly speaking, in addition to the preventive advice, which is mainly about smoking, that's the biggest with respect to lung cancer. But the second thing is early diagnosis and there are new ways to make diagnoses of lung cancer earlier. Third thing is the development of new kinds of therapies."
Varmus, who is currently the Lewis Thomas University Professor of Medicine at Weill Cornell Medicine and a senior associate at the New York Genome Center, said there are two major types when it comes to diagnostics.
"The first one I'm particularly knowledgeable about because it involves work that I and my colleagues have done over the years, It is to identify the genetic changes that have occurred in an individual's lungs over that person's lifetime, that are the causative agents of the disease," he explained.
"And we now have drugs that work in a very precise fashion to reverse the effects of those mutations. These so-called targeted drugs have had a very measurable benefit on the lifespan of somebody who's diagnosed with cancer. These are not curative but they're highly beneficial."
The scientist also highlighted the role of genetics in cancer diagnosis, saying the chances of different cancers arising vary if a person comes from a certain ancestry.
"We can use modern genetics, genome tools to try to understand the amount of risk that's conferred by your ancestry and make people more alert to certain kinds of cancers and seek attention if they have symptoms of those cancers," Varmus said.
"Early diagnostic procedures, when they're available, reduce the risk factors which may be exposure to certain environmental factors," the scientist said.
Varmus is in India at the invitation of the Indian Academy of Sciences to give a series of lectures that were scheduled to be held in 2020 but could not due to the pandemic.
He will be travelling over the next two weeks to Pune, Odisha and Bangalore to deliver lectures about the nature of science and about the kinds of work that he has done over the course of his career.
Varmus, who has previously been the director of the US National Cancer Institute, also emphasised the role of new immunotherapies -- that are based on changes in the immune system -- in lung cancer research.
"We now know that a certain percentage of patients with certain kinds of lung cancer -- this is not for everybody -- but for many people the use of agents that affect the immune system can prolong life to a degree we don't really fully understand," he added.
Every patient, he said, will not respond to these drugs, but some have a temporary reduction in their cancer.
Others seem to go on for as long as they have been receiving the drugs, which is often multiple years without recurrence of their cancer.
"So these are things that make me optimistic about our ability eventually to control lung cancer. But the thing I would always come back to emphasise when speaking of lung cancer, the best thing that any single person can do to protect their own bodies is not to smoke," the scientist added.
According to the World Health Organization, cancer accounted for nearly 10 million deaths in the world in 2020, with lung cancer accounting for 2.21 million cases.
The Indian Council of Medical Research (ICMR) notes that the number of lung cancer cases in India is expected to rise more than sevenfold by 2025.
Lung and breast cancers were the leading causes of cancer in men and women, respectively. Cases of lung and breast cancer are projected to be 81,219 and 2,32,832 (2.3 lakh) among males and females, respectively, for the year 2025.
In general, Varmus said, the principle of saying tobacco should be sold to people who are able to make sensible decisions is a good thing to do.
"Raising the age at which people smoke is a good thing but what we really want to do is get people to say, ‘I’m not gonna smoke because it's bad for my health’," he explained
In his view, certain lifestyle and behavioural changes can help bring down cancer cases in the country.
"Changes in behaviour like smoking, eating and chewing less 'paan' and getting immunised against hepatitis B virus and against human papillomavirus (HPV), which are major causes of cancer throughout the world, can help," Varmus said.
Several viruses are known to cause cancer. For example, HPV can cause cervical cancer and several other cancers. And hepatitis C can lead to liver cancer.