Value of cytology in small cell lung carcinoma diagnostic--single-center study

Small cell carcinoma of the lung (SCLC) together with the large cell neuroendocrine carcinoma (LCNEC), typical carcinoid (TC), and atypical carcinoid (AC) make a group of morphologically identifiable neuroendocrine tumors. The differential diagnosis of SCLC includes, first of all, other neuroendocrine tumors, and primary or metastatic non-small cell carcinomas. Although the criteria for the morphologic separation from other tumors of the lung are defined, in everyday practice it can be a problem, both in cytology and with histological samples. Accurate and early differentiation of the SCLC is important because it exhibits aggressive behavior, rapid growth, early spread to distant sites, but also exquisite sensitivity to chemotherapy and radiation. The study included 127 patients who underwent bronchoscopic examination or percutaneous transthoracic fine-needle aspiration (PTTFNA) during the period from early 2003 to 2007 in University Hospital Center Osijek whose cytological diagnosis was SCLC. The value of cytological diagnosis was determined by comparing it with histological findings obtained from a biopsy sample during bronchoscopy or on a resection specimen in 50 patients. In the remaining 77 patients, histological verification of cytological diagnosis was not made and the patients were treated based on cytological diagnosis of small cell carcinoma. In 76% of cases (38/50) cytological diagnosis of small cell lung carcinoma was also confirmed histologically. In 8% of cases (4/50) adenocarcinoma was histologically confirmed, in 10% (5/50) of the cases the squamous carcinoma was confirmed, and there was one case of urothelial carcinoma, one case of sarcoma and one undifferentiated carcinoma. Cytological diagnosis of SCLC was made in all cases in a brush smear while the catheter aspirate was positive in only 32 cases (25.8%). Median survival in the group of patients with histologically confirmed small cell cancer was 238 days, for women 250 days, and for men 237 days. Cumulative survival was 63.2% for 6 months, 26.3% for 12 months, 13.2% for 18 months and 7.9% for two years. In conclusion, cytology is a reliable and relatively non-invasive method for patients. Our results confirm that there is a good correlation between cytology and histology diagnoses, especially when it comes to malignant lesions. In determining the type of tumor cytology must be supported with additional methods, especially in cases when it is not possible to take samples for histological verification.