Assessing quality of care in early stage resected stage non-small cell lung cancer (NSCLC): An evaluation of epidermal growth factor receptor (EGFR) testing and adjuvant (adj) therapy (tx).
Authors: Mulherin Brian Patrick , Zeng Jia , Vasudevan Anupama , Alwon Erin , Gart Mike , Blanc Simon , Divers Stephen G. 
Published: June 2024

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Background: In December 2020, the FDA approved the use of osimertinib in the treatment of stage IB-IIIA (ES) NSCLC patients (pts) with EGFR exon 19 deletions and exon 21 L858R mutations (EGRFm) following tumor resection. Using real-world data, we sought to understand EGFR testing rates among ES pts and whether pts received osimertinib in the adjuvant setting based on EGFRm. Methods: We used the Integra Connect PrecisionQ real-world de-identified database of over 3 million cancer pts across 500 sites of care. From this database, we identified Stage IB – IIIA pts evaluated via medical chart curation who underwent lung cancer resection (R) between 12/1/2021 to 7/31/2023 (N = 803). We assessed adj treatment by stage, EGFR testing rates overall and by stage, EGFR testing rates by adjuvant treatment and non-adj treatment pts, timing of EGFR testing, and treatment rates with an EGFR TKI among EGFRm pts. Descriptive analyses were used and proportions were compared using a chi-squared test. Results: The mean age of the 803 ES R pts in the sample was 69 (SD = 8.3), 53.3% of the pts were female, , and 12% never smoked. We found adj treatment rates among ES R pts to be 56%; these were highest among stage IIIA (N = 245) pts at 70.2%, compared to stage IIB (N = 241) at 68.8%, stage IIA (N = 69) at 53.6% and stage IB (N = 240) at 31.7% (p < 0.001). Among ES R pts, 70% (N = 563) were tested for EGFR; this rate was 78% (N = 455) among ES pts who were R and received adj treatment, compared to 59% (N = 348) among ES R pts who did not receive adj treatment (p < 0.001). EGFR testing rates were highest among stage IIB pts at 76%, compared to stage IIIA pts at 73%, stage IIA pts at 72%, and stage IB pts at 60% (p < .001). Among ES pts who were R and tested for EGFR (N = 563), 14% were tested before surgery, 38% were tested after surgery but before adj treatment, and 48% were tested after initiating adjuvant therapy. EGFRm was found in 10.4% of EGFR tested pts. Among EGFRm ES R pts (N = 59), 54% were treated with an EGFR TKI. EGFRm ES R pts treated with an adj EGFR TKI were highest among stage IIB pts (N = 14) at 93%, compared to stage IIA pts (N = 5) at 60%, stage IB pts (N = 20) at 45%, and stage IIIA pts (N = 20) at 35% (p < 0.01). However, only 69% (N = 41) of EGFRm ES R pts received adj treatment (either chemotherapy or EGFR TKI) and among those pts, 78% (N = 32) received an EGFR TKI. Conclusions: Based on our findings using real-world data for EGFR testing and adjuvant osimertinib use, and in light of the published results from the ADAURA trial which showed disease free survival benefit (HR 0.2) and overall survival benefit (HR 0.49) of adjuvant osimertinib in ES NSCLC, we have identified an opportunity to improve patient outcomes following resection of ES NSCLC by increasing EGFR testing and encouraging treatment with EGFR TKI in exon 19 deletion or exon 21 L858R mutated pts.