Background: Extrapulmonary small cell carcinoma (EPSCCA) is often an underrecognized clinicopathologic entity, distinct from small cell lung carcinoma. The purpose of this study was to review the study institution's experience with EPSCCA with specific emphasis on the epidemiology and response to treatment of these uncommon neoplasms.
Methods: Using the tumor registry database of the study institution, the authors retrieved and reviewed the records of all patients with EPSCCA treated between 1974 and 1994. Study eligibility required that the patients had a normal chest radiograph, computed tomography scan of the chest, sputum cytology, and/or negative bronchoscopy. Patients with well differentiated neuroendocrine carcinomas and Merkel cell carcinomas of the skin were excluded.
Results: Primary sites of EPSCCA in the current series were: gastrointestinal system in 29 patients, ear, nose, and throat in 14, genitourinary system in 12, internal genitalia in 10, upper respiratory system in 5, unknown primary-lymph nodes in 5, unknown primary-other in 2, the thymus in 3, and the peritoneum in 1. After the initial evaluation and confirmation of histologic diagnosis, 10 of 81 patients had been lost to follow-up. Of the remaining 71 patients, 54 had limited disease. Forty of the 54 patients underwent surgical treatment of their malignancy; 10 patients (25%) remained alive and disease free at least 3 years after surgery, whereas 30 patients (75%) relapsed with a median disease free survival of 6 months. Six patients of 54 with limited disease were treated with chemotherapy and radiation. Five of these 6 (83%) relapsed at a median time of 11.5 months. Another 8 of the total of 54 patients received only radiation therapy and all had disease recurrence at a median time of 5 months. In the group of patients with extensive or recurrent disease, platinum-based chemotherapy was employed in 22 patients. There was a 72% response rate with a median duration of 8.5 months. Seven patients had doxorubicin-based chemotherapy. There was a 57% response rate with a median duration of 4.5 months. In the current study group of patients, the 3-year disease free and overall survival rates were 26% and 38%, respectively, whereas the 5-year disease free and overall survival rates were each 13%.
Conclusions: EPSCCA is usually a fatal disease, with a 13% 5-year survival rate. In a small percentage of patients, surgery can be curative if the tumor is small and confined to the organ of origin. Because of the poor overall outcome, one needs to consider the possible use of adjuvant chemotherapy in appropriate circumstances if surgery is to be employed. In most patients with limited disease, the combination of chemotherapy and radiation as the primary treatment can be as effective as surgery. EPSCCA is responsive to commonly employed regimens for small cell lung carcinoma; however, the responses are short-lived. The extent of disease at diagnosis represents the most sensitive predictor of survival.