THE IMPORTANCE OF POSTOPERATIVE RADIATION-THERAPY IN THE TREATMENT OF MERKEL CELL-CARCINOMA

Purpose: To determine the role of postoperative radiation therapy in the treatment of Merkel cell carcinoma (MCC). Methods and Materials: Eighty patients with MCC of the skin were treated with curative intent at the Queensland Radium Institute between 1981 and 1991. Fifty-one patients (63.7%) were referred after initial biopsy for further treatment and 29 patients (36.3%) were referred with locally recurrent disease following primary surgery elsewhere. Thirteen patients (16.3%) presented with nodal disease without a clinically definable primary skin lesion. Results: Of the 80 patients, 38 had undergone surgery (S) alone, 34 surgery plus radiotherapy (S + RT), 7 RT after incomplete S, and 1 patient had chemotherapy (CT) plus RT, Overall survival at 36 months for all patients was 68%, All of the 38 patients treated with S alone relapsed, The median time to recurrence was 5.5 months, Ten of the 34 patients treated with S + RT relapsed. The median time to recurrence was 16.5 months. Of the 80 patients, 55 have relapsed after primary treatment, 25 have developed systemic metastases, and 26 patients have died as a direct result of MCC. Conclusion: Our large series confirms earlier reports from this Institute and highlights the importance of S + RT over S alone in preventing local recurrence of this highly malignant skin cancer.