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P3.01 - Advanced NSCLC (Not CME Accredited Session) (ID 967)
- Event: WCLC 2018
- Type: Poster Viewing in the Exhibit Hall
- Presentations: 1
- Coordinates: 9/26/2018, 12:00 - 13:30, Exhibit Hall
P3.01-22 - An Exploratory Analysis of PD-L1 Expression and Smoking History in a Cohort of Advanced Non-Small Cell Lung Cancer Patients (ID 14052)
12:00 - 13:30 | Author(s): Kate Birchall
Response to PD-1 checkpoint inhibitors in NSCLC is associated with PD-L1 expression. One hypothesis is that high PD-L1 expression may correlate with tumour mutational load, the latter reflecting past tobacco exposure.a9ded1e5ce5d75814730bb4caaf49419 Method
We examined PD-L1 expression by tumour proportion score (TPS) in patients with advanced NSCLC and correlated this with the subjects’ smoking history. Number of pack-years was estimated by the same individual during the initial consultation. Demographic characteristics, performance status(PS), stage, histology were obtained from the electronic patient records. PD-L1 testing was performed using the Dako PD-L1 IHC 22C3 pharmDx test in all but 3 cases where the SP263 Roche antibody was used. We compared pack-years and smoking status of subjects with PD-L1 negative(TPS<1%), weakly-positive (TPS1-49%) and strongly positive (TPS≥50%) NSCLC.4c3880bb027f159e801041b1021e88e8 Result
Between 12/2016-3/2018, 54 biopsy specimens from 52 patients with advanced NSCLC were tested for PD-L1 expression at UHB. In 5 biopsies, material was not tested, as unsuitable in 4(<100 tumour cells present) and testing was cancelled in 1 patient who declined treatment. For the remaining 47 biopsies patient characteristics were: Median age 70 (43-82), male/female 26/21, PS 0/1/2/3-4 was 10/26/8/3, stage IIIA/IIIB/IV 3/18/26, histology adenoca/squamous/mixed 33/11/3. Median pack-years in PD-L1 negative 30(0-60), PD-L1 weakly positive 35(0-80), PD-L1 strongly positive 33(0-100); current+former smoker/never smoker numbers: PD-L1 negative 14/3(82.4%/17.6%), PD-L1 weakly positive 11/1(91.7%/8.3%), PD-L1 strongly positive 15/3(83.3%/16.7%). Strong/weak PD-L1 expression was seen in 3/1 never smokers; of these 2 had EGFR mutation. Weak expression was also seen in 1 ALK-positive NSCLC patient, former light smoker (5pack-years).
In this small retrospective cohort there were no differences in median pack-years of smoking or proportions of current+former/never smokers between PD-L1 negative and positive tumours. Smoking history alone may not be the only factor influencing PD-L1 expression. Never smoking status and EGFR-mutated/ALK-positive NSCLC should not be excluded from PD-L1 testing.6f8b794f3246b0c1e1780bb4d4d5dc53
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