For Americans in the last hundred years, no foreign war has matched cancer’s death toll: US military mortality in World War II was 407,300 over four years; US cancer mortality in 2015 alone is projected at 589,430. The moniker “War on Cancer” came from the 1971 National Cancer Act, initiating a kind of Manhattan Project or Moon landing effort to defeat this monster.
By the Act’s twenty-fifth anniversary in 1996, newspaper assessment nearly proposed that the war was over and cancer had won. Pessimism still rides high over curing cancer, but in fact, a cure may be closer than many imagine—depending on what one means by “cure.”
Only one human disease has ever been completely cured—that is, eradicated. Smallpox. It is unlikely cancer will end that way, but if its yearly death toll could be knocked down to that of, say, influenza and pneumonia (about 57,000), cancer mortality might be seen as a bygone terror, even if its incidence continued to rise.
But is that conceivable? Reasons exist to suspect it is.
Cancer’s annual mortality actually has been dropping slightly (about 1.8%) but steadily since 1992. The public health campaign against smoking deserves considerable credit for that, though lung cancer still takes the most lives. But what is most different since 1971 is the burgeoning knowledge field about the nature of malignancy and, consequently, how to arrest it.
Tumors are no longer classified solely by their location, but now by their “omics” (genomics, proteomics, metabolomics, etc). This involves diagnosing genetic pathways of uncontrolled tissue growth, and identifying cell surface proteins that can be therapeutic targets.
DNA sequencing has predictive capability, especially in situations such as testicular cancer where nearly half of the risk is inherited. Until very recently, invasive surgical biopsy was a necessary ordeal; now liquid biopsies that rely on mass spectroscopy to sort out the cellular debris in blood not only look extremely promising for determining an outcome after surgery, radiotherapy or chemotherapy, but also for tumor detection before it turns deadly through metastasis.
Surgery still provides the best separation between the patient and the tumor, but new approaches for “clearing the margins,” such as magnetomotive optical coherence elastography, improve the chances that no cancer cells are left behind.
Advances in cell engineering support a long held hope that a patient’s own immune system can distinguish healthy cells from cancerous ones and destroy tumors, while nanoparticles are in development to deliver drugs and imaging agents selectively to cancer stem cells.
While much research has gone into genetic strategies—such as restoring the function of the p53 tumor suppressor gene—other work has put forward tactics for shutting down the anaerobic metabolism that has made the deep interior of tumors so hard to attack.
There’s no question that cancer remains a formidable challenge, but in an age of accelerating medical innovation the odds for beating down this killer are improving. A “cure” is not unthinkable.