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P1.04 - Immunooncology (Not CME Accredited Session) (ID 936)
- Event: WCLC 2018
- Type: Poster Viewing in the Exhibit Hall
- Presentations: 1
- Coordinates: 9/24/2018, 16:45 - 18:00, Exhibit Hall
P1.04-16 - Comparison of Clinical Response to Checkpoint Inhibitors in Advanced NSCLC with High PD-L1 Expression Tested on Cytology Versus Biopsy Samples (ID 12525)
16:45 - 18:00 | Author(s): Alan Spatz
PD-L1 immunohistochemistry (IHC) expression correlates with clinical response to checkpoint inhibitors in advanced-stage NSCLC. PD-L1 IHC testing is usually performed on tissue blocks from core needle biopsy or surgical resection, but appears to be feasible on cytology cell blocks as well. In this retrospective study, we assessed the clinical response to checkpoint inhibitors in patients with NSCLC and high PDL1 IHC expression on cytology specimens in comparison with tissue biopsy specimens.a9ded1e5ce5d75814730bb4caaf49419 Method
Between August 2015 and April 2018, 116 patients with NSCLC received immunotherapy at our institution. Only cases with known PD-L1 expression from IHC testing performed on small biopsies or cytology cell blocks were included. A total of 65 consecutive cases were reviewed, including 40 small biopsies and 25 cytology samples. A Tumor Proportion Score (TPS) was categorized as high (≥ 50% tumor cell staining) or low (<50%). Response to treatment was categorized as disease control (DC, including complete and partial response and stable disease) or progression (PD). The primary outcome was the rate of disease control.4c3880bb027f159e801041b1021e88e8 Result
Patients were mostly current or ex-smokers (91%), Caucasians (82%) and non-squamous carcinomas (85 %). High TPS was seen in 44 (68%) cases. Immunotherapy was given in the first line setting in 20 (31%) patients, the second line in 36 (55%), and the third line in 9 (14%). 50 (77%) patients received Pembrolizumab, 10 (15%) Nivolumab and 5 (8%) others received immunotherapies on RCTs. Overall, there was DC in 40 (62%) patients and PD in 17 (26%). There was no significant difference in DC rate between the cytology and the small biopsy groups in high TPS group.
PD-L1 expression on cytology cell blocks and on small biopsies appears to have similar clinical significance. Further prospective trials are needed to confirm these findings.6f8b794f3246b0c1e1780bb4d4d5dc53
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