The Cancer Sleeper Cell

Siddhartha Mukherjee in The New York Times:

The word “relapse” comes from the Latin for “slipping backward,” or “slipping again.” It signals not just a fall but another fall, a recurrent sin, a catastrophe that happens again. It carries a particularly chilling resonance in cancer — for it signals the reappearance of a disease that had once disappeared. When cancer recurs, it often does so in treatment-resistant or widely spread form. For many patients, it is relapse that presages the failure of all treatment. You may fear cancer, but what cancer patients fear is relapse. Why does cancer relapse? From one perspective, the answer has to do as much with language, or psychology, as with biology. Diabetes and heart failure, both chronic illnesses whose acuity can also wax and wane, are rarely described in terms of “relapse.” Yet when a cancer disappears on a CT scan or becomes otherwise undetectable, we genuinely begin to believe that the disappearance is real, or even permanent, even though statistical reasoning might suggest the opposite. A resurrection implies a previous burial. Cancer’s “relapse” thus implies a belief that the disease was once truly dead.

But what if my patient’s cancer had never actually died, despite its invisibility on all scans and tests? CT scans, after all, lack the resolution to detect a single remnant cell. Blood tests for cancer also have a resolution limit: they detect cancer only when millions of tumor cells are present in the body. What if her cancer had persisted in a dormant state during her remissions — effectively frozen but ready to germinate? Could her case history be viewed through an inverted lens: not as a series of remissions punctuated by the occasional relapse, but rather a prolonged relapse, relieved by an occasional remission?

More here. (Note: Congratulations to dear friend and brilliant colleague, Sid. My MDS patients have hope because of you! BRAVO!)