Radiation best treatment for rare skin cancer, study finds

The study presents one of the largest single-institution datasets on Merkel cell carcinoma, which occurs in about 1,500 people in the United States annually. Most such cancers occur on the sun-exposed skin of white males and are first diagnosed at age 75, on average. Using the Kaiser Permanente Northern California Cancer Registry, the researchers found that out of 218 cases of Kaiser Permanente patients who had Merkel cell carcinoma, those who had radiation treatment had a 70 percent lower risk of disease recurrence while chemotherapy did not appear to have any impact on recurrence or survival.

"We used our database to show what characteristics impact recurrence and survival in this very rare cancer," said the study's lead author Maryam M. Asgari, MD, MPH, of the Kaiser Permanente Division of Research. "The electronic records allowed us to identify patients with Merkel cell carcinoma, see how they were diagnosed and treated, and then follow them over time to see how their care affected their outcomes."

Using an electronic health record system, Kaiser Permanente HealthConnect®, allowed the researchers to evaluate the relationships between cancer recurrence and survival with demographic information (age, sex, race, immunosuppression) and tumor characteristics (extent, size and location), as well as cancer work-ups (pathologic lymph node evaluation, imaging) and treatments (surgery, radiation and chemotherapy).

The study results also showed that immunosuppression and more advanced tumors were associated with worse survival rates related to Merkel cell carcinoma, and that pathological evaluation of the patient's lymph nodes also had a significant impact on outcomes.

Asgari noted that the success of different work-up and treatment protocols has been difficult to compare for rare cancers. "This research should help dermatologists and oncologists in caring for their patients with Merkel cell carcinomas," she said.