Should patients with extrapulmonary small-cell carcinoma receive prophylactic cranial irradiation?

INTRODUCTION: Extrapulmonary small-cell carcinoma (EPSCC) is a rare disease. Management is based on small-cell lung carcinoma. Prophylactic cranial irradiation (PCI) is not routinely administered in EPSCC. This study investigates the role of PCI in EPSCC, by analyzing the incidence, treatment, and survival of patients with brain metastases in a national cohort. Disease biology and epidemiology are also investigated.

METHODS: Patients diagnosed with primary EPSCC from the National Cancer Registry of Ireland from 1995 to 2007 were identified. The number of patients who developed brain metastases, their survival, and treatment data were documented. Patients who received PCI were investigated. Patient and disease characteristics, treatment, and survival data were stratified by stage and primary site.

RESULTS: Two hundred eighty patients were identified; 141 (50.4%) were men and 139 (49.6%) were women. One hundred eighty six patients (66.4%) had extensive-stage disease, 65 (23.2%) had limited-stage disease, and in 29 patients (10.3%) the stage was unknown. Eighteen patients (6.4%) developed brain metastases, with a median overall survival of 10.1 months. Eleven (61%) received cranial irradiation, and 12 (67%) received palliative chemotherapy. Two patients in the entire cohort (0.17%) received PCI. The most common primary sites included the esophagus (n = 43; 15.4%), cervix uteri (n = 17; 6.0%), bladder (n = 13; 4.6%), and prostate (n = 10; 3.6%). Median overall survival was 15.2 months (10.2-20.6) for limited-stage disease, 2.3 months (1.7-3.1) for extensive-stage EPSCC, and 3.7 months (1.3-8.3) for disease of unknown stage.

CONCLUSION: Brain metastases were uncommon in EPSCC compared with small-cell lung carcinoma. PCI is thus probably not warranted in this disease.