A team of City of Hope physicians and statisticians has shown that follow-up radiation therapy after surgery significantly improves survival for patients with Merkel cell carcinoma (MCC).
Published in the Journal of Clinical Oncology, the group’s findings shed much-needed light on treatment strategies following surgery for MCC, a rare but highly malignant skin cancer.
First author Pablo Mojica-Manosa, M.D., and Joshua D. I. Ellenhorn, M.D., both of the Department of Surgery, analyzed treatment data using a large database of cancer statistics called the Surveillance, Epidemiology and End Results registry. Biostatistician David Smith, Ph.D., of the Department of Information Sciences participated in the research as well.
MCC manifests itself as a lump of discolored cells growing in or right below the skin. It is routinely treated through surgical removal of the lump and any involved lymph nodes.
Few cases are reported in the United States — about 1,200 cases a year — but the cancer is difficult to eradicate. “This particular cancer has a very high likelihood of recurrence after surgical treatment,” said Ellenhorn. Overall, recurrence rates range from 50 to 79 percent, the authors wrote.
The good news, however, is that previous studies had suggested that MCC cells were “radiosensitive,” meaning that they are vulnerable to radiation treatment. Yet before this study, no one was sure whether radiation would truly benefit patients.
Mojica-Manosa, Smith and Ellenhorn surveyed 1,665 cases of MCC and found that only
40 percent of patients had received follow-up radiation, which is known as adjuvant therapy, after the tumor mass was removed. But that group had a median survival of 63 months compared to 45 months seen in patients who had not received radiation, a clear indication that radiation treatment improved patients’ prospects.
“Ours is the first study to show that use of radiation is beneficial at all stages and for all sizes of tumors, and improves survival,” said Ellenhorn. The benefits of radiation also were apparent across gender and race/ethnicity lines.
Even though less than half of those with the cancer nationwide now receive adjuvant radiation therapy, Ellenhorn says most MCC patients at City of Hope undergo the treatment, and he hopes the study will encourage the practice elsewhere. “Many physicians don’t know how to treat it,” he said. “The tumor looks innocuous and is managed by simple excision, and many physicians don’t think of treating it with radiation. The idea behind this paper was to use the largest possible database to determine whether radiation treatment was effective.”
Mojica-Manosa, a surgical oncology fellow at City of Hope, will be returning to his home in Puerto Rico in July when he completes a 2-year surgical oncology fellowship. He plans to undertake surgical oncology practice and teaching.
For more information about MCC go to www.cancer.gov/cancertopics/factsheet/Sites-Types/merkel-cell.