SESSION TITLE: Lung Cancer Screening & Diagnosis Posters
SESSION TYPE: Original Investigation Poster
PRESENTED ON: Wednesday, October 28, 2015 at 01:30 PM - 02:30 PM
PURPOSE: To report the yield of epidermal growth factor receptor testing based on the percentage malignant cells (PMC) in the pleural fluid.
METHODS: The clinical data of 1291 patients who had diagnostic thoracentesis for pleural effusion between January 2009 and July 2014 were reviewed. Data collection included demographics, prior lung cancer history, the histologic subtype, PET scan results, and volume of pleural effusion along with the PMC, Immunohistochemistry (IHC), and EGFR testing results. The study cytologist reviewed the cytology slides and the PMC was reported. PMC was divided into two categories <10% (PMC1) and >10% (PMC2). Using the pyrosequencing method, only patients in the PCM2 group were eligible for EGFR mutation testing.
RESULTS: Out of 1291 cases of thoracentesis, 143 had lung adenocarcinoma of which 61 (42.7%) had malignant pleural effusion. 38 of the 61 patients (62.3%) were in the PCM2 group, which represent the thoracentesis yield for EGFR testing eligibility. In PCM2 patients group, the yield of successful EGFR mutation testing was 95.5%. Only one patient in the PMC2 group did not have sufficient specimen for EGFR testing. As PMC increased, so did the rate of ordered molecular testing (p=0.018); while patients with low PMC tended to be older (p=0.039). The thoracentesis volume was not significantly different between PMC1 and PMC2. Pleural PET- avidity was not significantly different between PMC1 and PMC2.
CONCLUSIONS: The thoracentesis yield for EGFR testing eligibility is 62.3%. The yield of successful EGFR testing is 95.5%.
CLINICAL IMPLICATIONS: Using the pyrosequencing method, the overall throacentesis EGFR yield in patients with malignant pleural effusion secondary to adenocarcinoma is moderately low.
DISCLOSURE: The following authors have nothing to disclose: Hassan Hatoum, Ylagan Lourdes, Samjot Dhillon, Grace Dy, Juan Mena-Guerrero, Debra Dolan, Kassem Harris
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