In the next few years, cancer will become the leading cause of death in the United States. Later in this century, it is likely to be the top cause of death worldwide. The shift marks a dramatic epidemiological transition: the first time in history that cancer will reign as humankind’s number-one killer.
It’s a good news/bad news story. Cancer is primarily a disease of aging, and the dubiously good news is that we are living long enough to experience its ravages. Cancer’s new ranking also reflects public health’s impressive gains against infectious disease, which held the top spot until the last century, and against heart disease, the current number one.
The bad news is that cancer continues to bring pain and sorrow wherever it strikes. Siddhartha Mukherjee titled his magisterial biography of cancer The Emperor of All Maladies, quoting a 19th-century surgeon. He left out the second part of the surgeon’s epithet: “the king of terrors.” Modern targeted treatments and immunotherapy have in some cases led to wondrous cures, and many malignancies are now caught early enough so that their sufferers can live out full lives. But advances in treatment alone will never be enough to fully stem the burden of cancer.
As every public health professional knows, on a population level, the only way to substantially reduce incidence and mortality for any disease is through prevention. And on a broad scale, we have made far less progress preventing cancer than preventing its predecessor scourges. We tamed infections with sanitation and vaccines, abetted by antibiotics. We tamed heart disease through smoking cessation, better medical management of risk factors such as high cholesterol, and improved interventions for a condition that has clear points of intervention and responds more readily to lifestyle changes.
Cancer is a different story. Even today, it continues to occupy our collective imagination as the king of terrors: insidious, capricious, relentless. Anyone who has suffered cancer, or has suffered alongside a loved one with the disease—a considerable portion of the population, given that more than one in three of us will be diagnosed with a malignancy during our lifetime—knows the anguish and helplessness that trail the diagnosis.
In 2015, a study in Science seemed to confirm our primal fear. It argued that only one-third of the variation in cancer risk in tissues is due to environmental assaults or inherited genetic predispositions. The majority of risk, the researchers concluded, was due to “bad luck”—random mutations during normal DNA replication.
