The numbers are stark. Cancer claimed the lives of 8.8 million people in 2015, with only heart disease causing more deaths. Around 40% of Americans will be told that they have cancer during their lifetimes. It is now a bigger killer of Africans than malaria.
The statistics do not begin to capture the fear inspired by cancer’s silent and implacable cellular mutiny, however. Only Alzheimer’s exerts a similar grip on the imagination.
Confronted with this sort of enemy, people understandably focus on the potential for scientific breakthroughs that will deliver a cure. Their hope is not misplaced. Cancer has become more and more survivable in recent decades, owing to a host of advances, from genetic sequencing to targeted therapies.
The five-year survival rate for leukemia in America has almost doubled, from 34% in the mid-1970s to 63% from 2006 to 2012. America is home to about 15.5 million cancer survivors, a number that will grow to 20 million in the next 10 years. Developing countries have made big gains, too: In parts of Central and South America, survival rates for prostate and breast cancer have jumped by as much as a fifth in only a decade. From a purely technical perspective, it is reasonable to expect that science one day will turn most cancers into either chronic diseases or curable ones.
Cancer is not fought only in the lab, however. It is also fought in operating rooms, in schools, in public-health systems and in government departments. The dispatches from these battlefields are much less encouraging.
First, the good news. Caught early, many cancers now are highly treatable. Three out of four British men who received a prostate-cancer diagnosis in the early 1970s did not live for another 10 years, while today four out of five do. Other cancers, such as those of the lungs, pancreas and brain, are harder to find and treat. Nonetheless, progress is being made. Techniques to enable early diagnosis include a device designed to detect cancer on the breath, and blood tests can track fragments of DNA shed from tumors. Genome sequencing makes it ever easier to identify new drug targets.
The established trio of 20th-century cancer treatments—surgery, radiation and chemotherapy—are all still improving. Radiotherapists can create webs of gamma rays, whose intersections deliver doses high enough to kill tumors but which do less damage to healthy tissue as they enter and leave the body. Some new drugs throttle the growth of blood vessels bringing nutrients to tumors, while others attack cancer cells’ own DNA-repair kits. Cancer may be relentless, but so too is science.
The greatest excitement is reserved for immunotherapy, a new approach that has emerged in the past few years. The human immune system is equipped with a set of brakes that cancer cells are able to activate. The first immunotherapy treatment in effect disables the brakes, enabling white blood cells to attack the tumors. It is early days, but in a small subset of patients this mechanism has produced long-term remissions that are tantamount to cures. More than 1,000 clinical trials of such treatments are under way, targeting a wide range of different cancers. Now it is even possible to reprogram immune cells to fight cancer better by editing their genomes, with the first such gene therapy approved for use in America last month.
Cancer sufferers need not wait for the therapies of tomorrow, however, to have a better chance of survival today. Across rich and poor countries, the survivability of cancer varies enormously. Men die at far higher rates than women in some countries, while in other countries, at similar levels of development, they do comparably well. The five-year survival rate for a set of three common cancers in America and Canada is above 70 percent. Germany achieves 64 percent, whereas Britain manages a mere 52 percent.
Disparities exist within countries, too. America does well in its treatment of cancer overall, but suffers extraordinary inequalities in outcomes. The death rate of black American men from all cancers is 24 percent higher than it is for white males, and breast-cancer death rates among blacks are 42 percent higher than for whites. A diagnosis in rural America is deadlier than one in its cities.
Prevention remains the best cure of all, however. Efforts to rein in tobacco use averted 22 million deaths, many of them to cancer, between 2008 and 2014. However, only a tenth of the world’s population lives in countries where taxes make up at least three-quarters of the price of cigarettes, as recommended by the World Health Organization.
Taxes and budgeting are much less exciting than tumor-zapping proton beams and antibodies with superpowers, but the decisions of technocrats are as important as the work of technicians. Cancer kills millions of people, not simply for want of scientific advance, but also because of bad policy.
© 2017 Economist Newspaper Ltd., London (September 16). All rights reserved. Reprinted with permission.
Image credits: Jim Wilson/The New York Times