Lung Cancer Cytology: Can Any of the Cytological Methods Replace Histopathology?

Background: Diagnosis of lung cancer can be made in two ways: histopathological and cytopathological. Cytological methods in the diagnosis of lung lesions are generally thought to be one of the most successful tactics. Aims: This study aimed at comparing the efficiency of selected cytological techniques in lung lesions by correlating them with histopalhological diagnosis. In addition, we had answered the question whether any of the cytological methods can replace histopathology. Materials and Methods: The study group consisted of 633 patients and 1085 cytological specimens. Cytology samples included: induced sputum, bronchial washing (BW), bronchial brushing (BB), fine needle aspiration (FNA), and cell block (CB). In every case of CB immunocytochemistry (ICC) was performed. For each cytological method sensitivity, specificity, effectiveness, positive predictive value, and negative predictive value were assessed. Results: BW and BB showed the lowest diagnostic parameters. The most valuable diagnostic procedure was CB based on FNA. Close by CB, FNA had the highest diagnostic rate. However, possibility to evaluate tumor cell structure and apply the ICC, give CB an advantage over FNA. Using only morphologic criteria, we had subclassified nonsmall-cell lung cancer (NSCLC) into squamous cell carcinoma (SCC) and adenocarcinoma (AC) as 60.04% of SCC and 32.52% of AC. The use of CB and ICC decreased the NSCLC diagnoses from 22.1% to 2.8% while the percentage of AC and SCC diagnoses increased from 4.11% to 12.64% and from 6.64% to 11.06%, respectively. Metastatic lung tumors were diagnosed based on both the cell morphology and according to the ICC results. Conclusion: Despite the limitations of the cytological procedures, we recommend using CB and ICC to evaluate cytological samples derived from FNA. It can in many cases replace a conventional histopathology.