Merkel cell carcinoma arising in the head and neck - Optimizing therapy

Merkel cell carcinoma (MCC) is a rare and aggressive neuroendocrine dermal neoplasm. Because of the limited number of cases described in the literatur e (approximately 600 to date), statistically significant data regarding tre atment are difficult to obtain. The majority of MCC cases affect the head a nd neck and are thought to be caused by the actinic damage associated with sun exposure. This study evaluates cases of head and neck MCC at Naval Medi cal Center San Diego (NMCSD) and compares the treatment regimens and outcom es from multiple institutions. This study is a retrospective outcomes analy sis of all cases of head and neck MCC seen at NMCSD, between January 1, 198 8 and June 30, 1998. The records of the NMCSD Tumor Registry were searched for patients with that diagnosis, and supplemental information was retrieve d from the Radiation Oncology and Head & Neck Surgery Clinic charts. Eight of nine patients in this study were treated with either wide-local excision or Mohs microsurgery. The surgical margins were free of disease in all eig ht patients. One patient presented with distant metastatic disease, and two others were subsequently found to have nodal involvement. Subsequent thera py varied among the patients. Survey of the available literature revealed i nconsistency in terms of which treatment regimens are optimal. Tumor resect ions are recommended by most groups to include a 2-cm to 3-cm tumor-free ma rgin around the primary lesion when possible, but this is often difficult t o achieve in the head and neck. Data, which do not reach statistical signif icance, suggest improved outcomes with tumor-free margins. Treatment of the regional draining lymph nodes is also recommended in most series. Prophyla ctic lymph node dissection or radiation therapy to the nodal chain may decr ease local recurrence but does not consistently affect overall survival. Ad juvant chemotherapy is advocated by most groups in the treatment of metasta tic disease because MCC is pathologically similar to small-cell lung carcin oma. However, no chemotherapy protocol has been shown to improve survival. Head and neck MCC is a rare and aggressive dermal tumor of neuroendocrine o rigin that requires multimodality therapy, including surgery, radiation the rapy, and possibly adjuvant chemotherapy. Multiinstitutional studies are cr ucial to obtain sufficiently large populations to investigate and optimize therapy in this disease.