Pre- and postresection thoracic washings in non-small cell carcinoma of the lung: A cytological study of 44 patients without pleural effusion

Abstract

The presence of malignant pleural effusion in patients with non-small cell bronchogenic cancer has a poor prognostic significance and is indicative of advanced disease (T4, IIIB). The present study will investigate the role of cytology and identify the various cellular components seen in thoracic washings, in the absence of an effusion, and will identify the potential pitfalls in diagnosing these specimens. The sensitivity, specificity, and positive and negative predictive values will be determined, as well as the associated predictive factors. From November 1996 to July 1997, 96 thoracic washings were performed on 44 patients with non-small cell carcinoma of the lung prior to and following resection. The specimens were processed routinely. To assess the false-negative or false-positive cases, all cases were rescreened and then correlated with the surgical pathology. Seven (15.9%) patients had positive findings detected on the pre- and/or postresection thoracic washings. One (2.3%) patient had a negative preresection, but cytologically atypical cells were found on the postresection. Thirty-six (81.8%) patients had negative pre- and postresection thoracic washings. There were no false-positive diagnoses in the study; however, two false-negative diagnoses were made. The finding of positive cytology in 7 of 44 (15.9%) patients appears significant. Thoracic washings may provide evidence of cancer beyond the pleura in patients without pleural effusion which may be indicative of advanced disease.