Clinicopathological indicators of survival among patients with pulmonary carcinoid tumor

Abstract

Background: Pulmonary carcinoids (PC) are rare malignant neoplasms that cover approximately 1% of all lung cancers. PCs are classified by histological criteria as either typical (TC) or atypical (AC). Histological subtype is the most studied prognostic factor. The aim of this study was to evaluate if other tissue or clinical features are associated with patient outcomes.Material and methods: We retrospectively reviewed clinical records of 133PC patients who underwent operation in the Helsinki University Hospital between 1990 and 2013. Tissue specimens were re-evaluated, processed into tissue microarray format and stained immunohistochemically with serotonin, calcitonin, adrenocorticotropic hormone (ACTH), thyroid transcription factor-1 (TTF-1) and Ki-67. Survival and risk analyses were performed.Results: Based on histology, 75% (n=100) of the tumors were TCs and 25% (n=33) ACs. TCs had higher 10-year disease-specific survival (DSS) rate than ACs (99% (95% CI, 93-100%) for TCs vs. 82% (95% CI, 61-92%) for ACs). Hormonally active tumors expressing serotonin, calcitonin or ACTH were noted in 53% of the specimens but hormonal expression was not associated with DSS. TTF-1 was positive in 78% of the specimens but was not associated with DSS. Ki-67 index varied between