Background-Despite abundant evidence of racial disparities in the use of surgical procedures, it is uncertain whether these disparities reflect racial differences in clinical appropriateness or overuse or under-use of care.

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Introduction MET gene copy number gain (CNG) may be a predictive biomarker for MET inhibition in lung cancer, but the most appropriate method and criteria for defining MET positivity are uncertain. Methods MET copy number was assessed by fluorescence in situ hybridization (FISH) in lung adenocarcinoma. Positivity criteria included mean MET/cell ≥5 (low ≥5 – <6, intermediate ≥6 –<7, high ≥7) and MET/CEP7 ratio ≥1.8 (low ≥1.8 – ≤2.2, intermediate >2.2 – < 5, high ≥5). Associated clinical and molecular characteristics were captured. Results 99/686 cases (14%) had mean MET/cell ≥ 5, 52/1164 (4.5%) had MET/CEP7 ≥1.8. Other oncogenic drivers (in EGFR, KRAS, ALK, ERBB2, BRAF, NRAS, ROS1 or RET) were detectable in 56% of the mean MET/cell ≥ 5 group and 47% of the MET/CEP 7 ratio ≥1.8 group, suggesting many MET ‘positive’ cases are not truly MET-addicted. Concomitant drivers in low, indeterminate and high categories of mean MET/cell were 32/52 (62%), 12/19 (63%) and 11/27 (41%) (p=0.2) and in MET/CEP7: 15/29 (52%), 9/18 (50%) and 0/4 (0%) respectively (p=0.04). MET/CEP7 ≥1.8, in the absence of other oncogenes, was associated with a higher rate of adrenal metastases (p=0.03), but not with never smoking status. Conclusions FISH MET/CEP7 ≥ 5 defined a MET ‘positive’ group with no oncogenic overlap. As this method and criteria are also associated with the highest response rate to MET inhibition it represents the clearest definition of a MET CNG-addicted state. However, a MET-associated phenotype may also exist across MET/CEP7 ≥ 1.8 cases when no other oncogene overlap occurs.

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Introduction Osimertinib is an Epidermal Growth Factor Receptor (EGFR) Inhibitor licensed for the treatment of EGFR mutant, T790M positive, non-small cell lung cancer (NSCLC). Previously unreported, common, transient asymptomatic pulmonary opacities (TAPOs) were noted at the University of Colorado in patients during osimertinib therapy. Methods CT imaging and clinical notes of NSCLC patients treated at the University of Colorado with osimertinib were retrospectively reviewed. Results Seven of twenty patients (35%), developed TAPOs while on osimertinib. The radiological patterns seen included ground-glass opacities with/without nodular consolidation. The median time to first lesion development was 8.7 weeks (range: 1.6 – 43 weeks) and 6 weeks (range: 1 – 11 weeks) to resolution during continued osimertinib. Conclusions TAPOs may be a previously unrecognized, benign feature associated with osimertinib therapy, which may be mistaken for isolated pulmonary progression or the beginning of more severe pneumonitis. If new onset pulmonary lesions, especially those associated with ground-glass appearances, are asymptomatic, localized and there is no evidence of disease progression elsewhere it may be reasonable to continue treatment with osimertinib and monitor these lesions for resolution.