Radiation safe in Merkel cell carcinoma; resulted in low local regional failure

Lok B. Cancer. 2011;doi:10.1002/cncr.26738.

Issue: January 25, 2012

The use of radiotherapy in the treatment of patients with Merkel cell carcinoma appeared to be well tolerated in a group of site-specific patients with adverse features, according to the results of a study conducted at Memorial Sloan-Kettering Cancer Center.

The purpose of the study was to examine the rates and patterns of failures in patients who had undergone radiotherapy for Merkel cell carcinoma of the head and neck, the practice of which is controversial.

To examine these rates, researchers studied the records of 145 patients with the disease between 1988 and 2009. Forty-eight patients were identified who had received radiotherapy at the institution.

“Despite the presence of adverse clinical and pathologic features in many patients,” only five patients (10%) experienced locoregional recurrence at 5 years, the researchers said.

Two of those five patients had locoregional failures that were local and at the edge of the radiation treatment field. The other three patients had failures occur in the lymph nodes, outside the treatment field.

“The propensity for Merkel cell carcinoma to recur at the edge of the treatment field suggests that generous margins are appropriate when radiation therapy is administered,” the researchers wrote.

Twenty-five percent of patients developed distant metastatic failure. Overall, the rates of locoregional failure, disease progression and disease-specific death were low (see Table).

“Further work is needed to determine clinical, histopathological and molecular features that identify the patients who are most likely to benefit from adjuvant radiation therapy,” the researchers wrote.

Table. Outcomes at 5 years post radiation in Merkel cell carcinoma (n=145)

Outcome	Percentage of patients
Locoregional failure	10%
Disease progression	30%
Disease-specific death	21%

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