The New York Times: Genetic Tests May Reveal Source of Mystery Tumors

When Jo Symons was found to have cancer, there was an extra complication: doctors could not tell what type of cancer she had.

Tumors were found in her neck, chest and lymph nodes. But those tumors had spread there from someplace else, and her doctors could not determine whether the original site was the breast, the colon, the ovary or some other organ. Without that knowledge, they could not offer optimal treatment.

Such mystery tumors are estimated to account for 2 percent to 5 percent of all cancer, or at least 30,000 new cases a year in the United States, making them more common than brain, liver or stomach cancers. For patients, such a diagnosis can amount to a double agony — not only do they have cancer, but doctors cannot treat it properly.

“You don’t believe that in the 21st century it is possible for the medical profession not to know where the cancer is coming from,” said Ms. Symons’s husband, John.

But now 21st-century medicine may help. New genetic tests may pinpoint the origin of the mystery tumors. The tests, which cost more than $3,000 each, still need to prove their worth better, experts say, though some of them are hopeful.