
So-called rare cancers, in one important respect, aren’t so rare at all. Diseases like retinoblastoma, Merkel cell carcinoma, and others actually account for 20 percent of all malignancies, and cause more deaths among younger people than the “big four” (lung, colon, breast, and prostate cancer).
But the patient groups are so fragmented, and the potential market for cures so thin, that researchers have little ability or incentive to attack these diseases, leaving patients with little hope or access to cutting-edge treatments.