The effect of radiometabolic properties on bronchoscopic cytopathology results in lung cancers: A multicenter retrospective study.

Background: Cytologic examination of bronchial washing fluid (BWF) in lung cancers (LC) has a low diagnostic rate. This study investigated the relationship between the cytologic diagnostic success of bronchial washing performed with fiberoptic bronchoscopy (FOB) in lung cancer cases and the radiometabolic (PET-CT) characteristics of the tumor.

Materials and methods: FOB reports of cases with a final diagnosis of lung cancer (LC) in our hospital bronchoscopy unit were scanned and the files of cases sent for BWF cytology were retrospectively reviewed. The clinical, demographic, radiologic, and PET-CT characteristics of the cases, and other diagnostic procedures performed during the FOB procedure were recorded. BWF cytologic examinations were divided into two groups as diagnostic and non-diagnostic. The characteristics of both groups were compared with each other.

Results: A total of 163 patients were included in the study, 118 (72.4 %) were male, 45 (27.6 %) were female, and the mean age was 65.4 years. In 75 (46 %) cases, BWF cytologic examinations were diagnostic and in 88 (54 %) cases they were non-diagnostic. The mean SUVmax value in the BWF diagnostic group was 15.8 ± 8.6 and in the non-diagnostic group it was 12.6 ± 7 (p = 0.015). In the ROC analysis, the optimal SUVmax cut-off value for predicting BWF diagnostic success was 12 (AUC: 0.617). At SUVmax 12 and above, the sensitivity was 70 % and specificity was 51 %. In the regression analysis performed for the independent factors affecting the diagnostic success of BWF cytologic examination, the SUVmax value was one of the independent factors (p = 0.026).

Conclusions: In LCs with relatively high SUV max values, the chance of diagnosis may be high in BWF cytologic examinations performed with FOB.