The world is winning the war on cancer

Hindustan Times

2 days ago

IN 1971 RICHARD NIXON, then America's president, announced a 'war on cancer'. Just two years earlier the Apollo programme had combined big science and big government to put astronauts on the Moon, so hopes were high. Some optimistic doctors talked of a cure for cancer within a few years.
They were wrong. Today every adult has had cancer, knows someone who has, or both. Half of men and a third of women in rich countries can expect to suffer from it at some point in their lives. In America, where it is the second-most-common cause of death, just behind heart disease, it kills around 600,000 people a year. Worldwide, it is responsible for about one in six of all deaths. If your criterion for success was a cure within a decade—or even two or three or four—then you might conclude that the war on cancer has been lost.
In fact, things are better than many realise. The progress is plain from the data and there is every reason to think it will continue. Cancer is related to age. If you strip out longer lifespans, it becomes clear that in the rich world the early 1990s were an inflection point. Since then, the age-adjusted death rate has been falling, slowly but steadily, year after year. In America the rate is now about a third lower than in the 1990s. The trend is similar in other developed countries.
What some scientists hoped would be a blitzkrieg has turned out to be a steady but successful war of attrition. Some victories have been spectacular. Childhood leukaemia used to be virtually a death sentence; now it has a five-year survival rate above 90%. Yet because cancer is not one illness, but a whole category, much of the progress has come not from big breakthroughs, but thousands of smaller advances in screening, surgery and drugs.
Future gains will come from three main sources. Some will come by applying lessons from the rich world all across the globe. The overlooked success story in the fight against cancer has been prevention—perhaps because cancers that never happen are less visible than those that are cured. For example, smoking rates have plummeted in rich countries. That has probably prevented more than 3m cancer deaths since 1975 in America alone. Because smoking still causes one in five cancer deaths around the world, anti-tobacco drives in poor and middle-income countries, where smoking remains common, stand to do an enormous amount of good.
Another source of progress will be cheaper medicines and extra wealth to pay for them. Cervical cancer is one of the most common cancers in women. Almost all cases are the delayed side-effect of infection with the human papillomavirus (HPV), a bug. In 2008 Britain began offering a newly developed HPV vaccine to teenage girls. A decade and a half later, rates of cervical cancer among women in their 20s are down by 90%, and British health officials talk of virtually eradicating cervical cancer by 2040. The original HPV vaccine was relatively expensive. But a cheaper version developed in India now underpins a mass-vaccination campaign in that country, too.
And the last source of progress will be the clinical application of fresh science. This comes in two steps: identifying who is most at risk of developing a cancer, and then finding ways to stop the disease in its tracks. As we report this week, both hold promise.
Scientists already know of genetic variants that predispose their carriers to certain kinds of cancer, such as a faulty BRCA-1 gene that raises the risk of breast or prostate cancer. However, less than half of all cancer patients have a known risk factor. Similarly, only some pre-cancerous cells turn malignant. For example, bowel cancers tend to emerge from polyps, but only 5-10% of polyps become cancerous.
The aim is to untangle this confusion in order to identify patients very early, when treatment is most effective. That work draws on huge biobanks of tissue samples and on the ability to watch genes switch on and off in living cells—impossible even a decade ago. Armed with new biomarkers in blood or breath and a deeper understanding of how combinations of genes and environmental exposure predispose people to develop cancers, physicians can target those who would benefit from treatment. That is important to prevent people undergoing needless surgery, chemo- and radiation therapy, at vast expense and with severe side-effects.
Having worked out whom to treat, doctors can make use of an expanding arsenal of therapies. Some cheap drugs seem to act as cancer prophylactics. Aspirin, a painkiller, seems to cut the risk of bowel cancer in half when given to those with Lynch syndrome, a genetic disorder that predisposes sufferers to some types of cancer. Metformin, a cheap diabetes drug, cuts the risk of recurrence in women who have been treated for a particular type of breast cancer. GLP-1 receptor agonists such as Ozempic show promise, too.
Alongside the mainstays of surgery, chemotherapy and radiotherapy a new technique is emerging that harnesses the power of the immune system. The idea is to boost the body's own ability to attack cancerous cells. Some vaccines—perhaps genetically tailored to individual patients—can target a cancer that is already established. Others, acting more like broad vaccines used against diseases such as the flu, could target pre-cancerous cells. Vaccines of this sort for breast and colon cancer are in clinical trials.
Bucking onco
Good news often goes unreported, especially if it happens gradually. That is the story of the war on cancer. Not everything is perfect: treatments are costly, drug firms worry about being sued for side-effects when treating people for diseases they do not yet have, and the Trump administration is planning steep cuts to the National Cancer Institute—setting back the science and putting off a generation of researchers. But costs will fall, treatments will find their way to market and work goes on in Europe and China, which this year overtook America as the main source of cancer research. That is why the age-adjusted death rate will continue falling, year after year.
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