Rare skin cancer deadlier than melanoma, yet studied little

The deadliest form of skin cancer is a little-studied type most people have probably never heard of.

Merkel cell carcinoma provides a poignant glimpse of the desperate intersection of research dollars and the suffering wrought by rare diseases.

It's a cancer only recognized as distinct from melanoma — even more aggressive, and needing different treatment — about 15 years ago. Diagnoses have tripled to about 1,500 a year in the United States.

Here's the rub: The first sign is a painless bump, often reddish to purple, that can resemble a benign cyst, confusing even dermatologists about whether a biopsy's needed. But Merkel cell carcinoma spreads rapidly once that bump appears. A third of patients die in three years, double melanoma's mortality.

Yet there have been no well-controlled studies of the best treatment. Intense radiation is key — unlike melanoma, Merkel cell carcinoma seems unusually radiation-sensitive, says Nghiem. There is no evidence that adding chemotherapy
right away helps, and it may even worsen patients' chances, he adds.

Only last month was the first comprehensive report on symptoms and risk factors published. It almost exclusively hits Caucasians, over age 50, on sun-exposed skin. And while a weak immune system greatly increases risk, most patients, puzzlingly, have normal immunity.

Then in January, University of Pittsburgh scientists announced they'd discovered a previously unknown virus lurking inside Merkel cell tumours, a virus that just may be the cancer's trigger.

"If we'd had funding, we could have done this easily five years ago," says lead researcher Dr. Patrick Moore.

Despite earlier success discovering another cancer virus, Moore couldn't win government money for the Merkel cell research and spent years cobbling together dollars to do it. The next step, also so far unfunded, is to create a blood test for this "Merkel cell polyomavirus," to see how common it is and why it only rarely harms.

Indeed, for two decades, Merkel cell research has depended on small pilot grants and family fundraising like Whatley's, says Nghiem. Last week, he won what is believed the disease's biggest research grant to date, $840,000 US from the American Cancer Society.

Fewer patients, no profits

Rare diseases always struggle against more common killers for funding.

"There's no money invested in finding a cure because there's no profit margin, there's so few patients," says George Campbell of Charleston, S.C., who founded a Google-based support group for Merkel cell patients after his 2005 diagnosis.

Meanwhile, a small fraternity of Merkel cell patients has banded together to push education, of doctors and the newly diagnosed — both to help them navigate the frightening treatment maze, and to urge them to donate tumour-tissue samples to Nghiem's lab.

"The time it takes, the research, there's just not an awareness of this at all," says Keith Boyer, 72, of Burlington, Iowa, whose Merkel cell hasn't returned since radiation two years ago.