Should patients with extrapulmonary small cell carcinoma receive prophylactic cranial irradiation? An Irish experience.

Abstract

2609 Background: Extrapulmonary small cell carcinoma (EPSCC) is a rare disease. Management is based on small cell lung carcinoma, and experience of disease biology on single institution studies. 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. Secondary aims were to investigate disease biology and epidemiology. Methods: An audit was undertaken of patients diagnosed with primary EPSCC from the National Cancer Registry of Ireland, between 1995-2007. The number of patients who developed brain metastases, received cranial radiotherapy, and their survival data, were documented. Patient and disease characteristics, treatment, and survival data stratified by stage and primary site, were tabulated. Results: 280 patients were found. 141 (50.4%) patients were male, and 139 (49.6%) were female. 186 (66.4%) patients had extensive stage disease, 65 (23.2%) had limited stage disease, and in 29 (10.3%) patients the stage was not known. 17 patients (5.4%) developed brain metastases, 11 of which (64.7%) received cranial irradiation. These patients had a median progression-free survival (PFS) of 5.2 months, and a median overall survival (OS) of 10.2 months. The commonest primary sites were the oesophagus (n=43, 15.4%), cervix uteri (n=17, 6.0%), bladder (n=13, 4.6%) and prostate (n=10, 3.6%). There were 315 events of distant metastasis, and 21 local recurrence events. The commonest metastatic sites were the liver, 110 (34.9%), lymph nodes 58 (20.7%), lung 38 (12.1%), and bone 36 (12.8%). The median PFS and OS for limited stage EPSCC was 8.8 months and 14.9 months, and 1.5 months and 2.3 months for extensive stage EPSCC. Conclusions: Brain metastases were uncommon in this cohort (5.4%), and patients lived longer, suggesting a low rate of mortality from brain metastases. PCI is thus probably not warranted in EPSCC. Prospective data are necessary to support PCI in EPSCC. This is one of the largest datasets on EPSCC, providing insights into disease biology.