Closing in on cancer

皇后

Science will win the technical battleagainst cancer. But that is onlyhalfthe fight

The numbers are stark. Cancer claimed thelives of 8.8m people in 2015; only heart disease caused more deaths.
Around 40% of Americans will be told they have cancer during their lifetimes.It is now a bigger killer of Africans than malaria.
But the statistics do not begin to capture the fear inspired by cancer’s silentand implacable cellular mutiny. Only Alzheimer’s exerts a similar grip on theimagination.
Confronted with this sort of enemy, people understandably focus on thepotential for scientific breakthroughs that will deliver a cure. Their hope isnot misplaced. Cancer has become more and more survivable over recent decadesowing to a host of advances, from genetic sequencing to targeted therapies. Thefive-yearsurvival rate forleukemia in America hasalmost doubled, from 34% inthe mid-1970s to 63% in 2006-12.
America is home to about 15.5m cancer survivors, a number that will grow to 20min the next ten years. Developing countries have made big gains, too: in partsof Central and South America, survival rates for prostate and breast cancerhave jumped by as much as a fifth in only a decade. From a purely technicalperspective, it is reasonable to expect that science will one day turn mostcancers into either chronic diseases or curable ones. But cancer is not foughtonly in the lab. It is also fought in doctors’ surgeries, in schools, in public-healthsystems and in government departments. The
dispatches from these battlefields are much less encouraging.
Cell-side research
First, the good news. Caught early, many cancers are now highlytreatable. Three out offour British men who received a prostate-cancer diagnosisin the early1970s did not live for another ten years; today four out of fivedo. Other cancers, such as those of the lung, pancreas and brain, are harder tofind and treat. But as our Technology Quarterly in this issue shows, progressis being made. Techniques to enable early diagnosis include a device designedto detect cancer on the breath; blood
tests can track fragments ofDNA shed from tumours. Genome sequencingmakes it ever easier toidentify 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 deliverdoses high enough to kill tumours but which do less damage to healthy tissue asthey enter and leave the body. Some new drugs throttle the growth of bloodvessels bringing nutrients to tumours; others attack cancer cells’ own DNA-repair kits. Cancermay be relentless;so too is science.
The greatest excitement is reserved for immunotherapy, a new approach that hasemerged in the past few years. The human immune system is equipped with a setofbrakes that cancer cells are able to activate; the first immunotherapytreatment in effect disables the brakes, enabling white blood cells to attackthe tumours. It is early days, but in a small subset of patients this mechanismhas produced long-term remissions that are tantamount to cures. Well over 1,000clinical trials of such treatments are underway, targetinga wide range ofdifferentcancers. It is even now possible to reprogram immune cells to fight cancerbetter by editing their genomes; the first such gene therapy was approved foruse in America last month.
Yet cancer sufferers need not wait for the therapies of tomorrow to have abetter chance of survival today. Across rich and poor countries, thesurvivability of cancer varies enormously. Men die at far higher rates thanwomen in some countries; in other countries, at similar levels of development,they do comparably well. The five-year survival rate for a set of three commoncancers in America and Canada is above 70%;
Germany achieves 64%, whereas Britain manages a mere 52%.
Disparities existwithin countries, too. America does well in its treatment ofcancer overall, but suffers extraordinary inequalities in outcomes. The deathrate of black American men from all cancers is 24% higher than it is for whitemales; breast-cancer death rates among blacks are 42% higher than for whites. Adiagnosis in rural America is deadlier than one in its cities.
Practical as well as pioneering
Variations between countries are partly a reflection of healthcarespending: more than halfofpatients requiring radiotherapy in low- andmiddle-income countries do not have access to treatment. But big budgets do notguarantee good outcomes.Iceland and Portugal do not outspend England andDenmark on health care as a proportion of GDP, but past studies show wide variation in survivability in allcancers. Instead, the problem is often how money is spent, not how much of itthere is. To take one example, a vaccine exists against the humanpapillomavirus (HPV),which causes cancers ofthe cervix in women, as well as cancers ofthe head andneck.Rwanda started a programme of routine vaccination in2011, and aims to eradicatecervical cancer by 2020. Other countries are far less systematic. Vaccinationscould help prevent cervical cancer in 120,000 Indian women each year.Policymakersarenotpowerless. More can be done to verify which treatments (and combinationsthereof) work best. A￡1.3bn ($2bn) cancer-drugfund in England, which madeexpensive new medicines easier to obtain, did not assess the efficacy of thedrugs it provided—a huge missed opportunity. Measuring the incidence andsurvival of cancer, through cancer registries, spotlights where patients arebeing failed. Access to health care matters, too: the number of Americans whosecancers were diagnosed at the earliest possible opportunity went upafterObamacare was enacted. And prevention remains the best cure of all. Efforts to rein in tobacco use averted 22m deaths (many ofthem to cancer) between 2008 and 2014. Yet only a tenth ofthe world’spopulation lives in countries where taxes make up at least three-quarters ofthe price of cigarettes, as recommended by the World Health Organisation.Taxes and budgeting are a lotless excitingthan tumour-zapping proton beams and antibodies with superpowers.But the decisions of technocrats are as important as the work of technicians. Cancerkills millions of people not simply for want of scientific advance, but alsobecause of bad policy