[482] EBUS-TBNA Cytology of PET Positive Verse PET Negative Lymph Nodes. A Retrospective Study with Histology Correlation

R Zheng, R Yung, D Clark, QK Li. The Johns Hopkins Hospital, Baltimore, MD

Background: Positron emission tomography (PET) is a widely used procedure in the assessment of lymph node (LN) status in the staging of lung cancer patients. Clinically, a PET positive LN often requires histological confirmation of malignancy, since an increased FDG uptake may be related to non-neoplastic processes. Endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) is a recently developed technique for diagnosing and staging of the lung cancer. However, only a few studies have investigated the correlation between EBUS-TBNA cytology and PET scan findings. In this study, we have reviewed the EBUS-TBNA cytological features of PET positive LNs verse PET negative LNs.
Design: Cytological cases of EBUS-TBNA with PET scan were searched over a period of 12 months from a major medical center. A total of 105 cases were selected, including 129 PET positive and 48 PET negative LNs. Among 105 cases, 67 cases (63.8%) had corresponding surgical material which was also reviewed and correlated.
Results: The location of LNs were as follows: 3.1% of 2(L+R), 13.2% of 4L, 31.8% of 4R, 24.8% of 7, 27.1% of intrapulmonary. The size of PET positive LNs ranged from 0.5 to 3.9 cm with average of 1.2 cm, whereas the PET negative LNs ranged from 0.8 to 3.8 cm with average of 1.6 cm. The cytological diagnoses were summarized in Table 1.

Table1. Cytological diagnoses of lymph nodes.
DiagnosesPET positive LNsPET negative LNs
Number (%)Number (%)
Reactive20(15.5)19(39.6)
Granuloma11(8.5)7(14.6)
Malignant75(58.1)6(12.5)
Suspicious for ca10(7.7)1(2.1)
Non-diagnostic13(10.1)15(31.3)
Total129(100%)48(100%)



Conclusions: Approximately 60% of PET positive LNs were confirmed by EBUS as malignant, 24% of the PET positive LNs were reactive or granulomatous inflammation; the non-diagnostic rate of PET positive LNs was 10%, whereas approximately 10% of PET negative LNs were diagnosed as malignant by EBUS, approximately 55% of PET negative LNs were reactive or granuloma, and the non-diagnostic rate was 30%. Our data suggest that EBUS-TBNA is necessary to confirm the PET findings, and EBUS may pick up additional 10% of PET negative malignant LNs in the staging of lung cancers.
Category: Cytopathology

Tuesday, March 23, 2010 2:30 PM

Platform Session: Section D, Tuesday Afternoon

 

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