Merkel cell carcinoma therapy depends on tumor stage, patient health

Key Points

St. Louis - Merkel cell carcinoma (MCC) is a neuroendocrine tumor of the skin that is very aggressive and potentially lethal. As such, treatment approaches and disease management should also be aggressive and appropriately address the patient's disease and symptoms. Treatment choices depend on the stage of the tumor, however, as well as the general health of the affected patient, according to Ryan C. Fields, M.D., Barnes-Jewish Hospital, Washington University School of Medicine, St. Louis.

"Different therapeutic options are available for the treatment of MCC, however, adjunct therapy such as radiation and chemotherapy should be reserved for particular patient populations who would derive the most benefit from such therapeutic measures," Dr. Fields says.

Disease stage

According to Dr. Fields, a wide local excision of the primary tumor is typically recommended. A clear distinction must be made, however, between those patients who present with clinically involved or palpable lymph nodes that can be found on physical examination versus those patients who just have isolated disease to that primary tumor on physical examination.

Because MCC is a very radiosensitive tumor, Dr. Fields says some centers will advocate radiation therapy to the primary tumor in the very elderly and/or debilitated patients or where MCC is found in very cosmetically sensitive areas. But Dr. Fields says he and many of his colleagues believe that the evidence backing this approach is not strong.

Radiation therapy could be the treatment of choice in those patients who are contraindicated for surgery, but, according to Dr. Fields, this scenario is not very common because there are few patients who would be too sick to undergo superficial skin surgery.

"Surgical excision remains the optimal and widely accepted treatment approach and I would always recommend a wide local excision of the primary tumor whenever possible. In larger cases, flaps and/or graft techniques could be employed to close larger defects if needed," Dr. Fields says.

Minding margins

If the pathology report of the excised primary tumor shows very close or positive margins, Dr. Fields suggests either a re-excision or following up with radiation therapy. A re-excision is generally recommended because it is a one-time treatment and relatively simple to do, he says. However, if the surgical site is in an area that cannot be re-excised without a larger operation or if it is a cosmetically sensitive area, he says he recommends radiation treatment.

Following a wide local excision of the primary tumor, Dr. Fields says he usually also performs a lymph node biopsy to try to determine whether the tumor has spread microscopically to the lymph nodes, the results of which would guide further treatment.

"In a patient with a positive sentinel lymph node biopsy, we typically would either recommend completion lymph node dissection removing all the lymph nodes in the area or radiation therapy, but not both because though it is crucial to clear the patient of tumor cells, we do not want to overtreat the patient," Dr. Fields says.