Physician attitudes and prevalence of molecular testing in lung cancer
Background EGFR mutations and EML4-ALK rearrangements are key therapeutic targets in nonsquamous non–small-cell lung carcinoma (nsNSCLC). Current guidelines recommend testing all patients with advanced nsNSCLC (stages IIIB and IV).
Objective To evaluate physician attitudes about molecular testing for nsNSCLC and to determine the rate of testing, the effect of biopsy sample size, and prevalence of driver mutations.
Materials and methods In this retrospective study, 206 cases of advanced nsNSCLC were identified from the tumor registry from 3 hospitals within a health network (February 2011-February 2013). EGFR and ALK testing was performed using commercial laboratories and mutation prevalence was determined. A survey was sent to practitioners who care for patients with lung cancer to evaluate their attitudes toward molecular testing.
Results The prevalence of EGFR mutation (7.8%) and ALK rearrangement (2%) was lower than reported in the literature. Large biopsy samples were more likely to be analyzed for EGFR mutations and ALK rearrangements (P = .023 and P = .007, respectively) than were smaller samples. There was a high level of agreement among survey respondents that mutation testing was essential. Nevertheless, we found that fewer than half of the eligible patients had been tested for these critical driver mutations.
Limitations Small sample size
Conclusion Despite current recommendations to test patients with advanced nsNSCLC for EGFR mutations and ALK rearrangements and physician assertions that they deemed mutation testing essential, fewer than 50% of the patients at the 3 hospitals had been assayed. Our findings imply that large biopsy samples, such as those from surgical or core biopsies, are better than small samples, such as those from needle aspiration for the purpose of molecular testing. In addition, the prevalence of driver mutations among patients who were treated at the cancer center is lower than that published in the literature.
Accepted for publication January 9, 2017
Correspondence Rohit Rao, MD; rohit.rao@ahn.org
Disclosures The authors report no disclosures/conflicts of interest.
Citation JCSO 2017;15(3):e147-e154
©2017 Frontline Medical Communications
doi https://doi.org/10.12788/jcso.0326
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Conclusions
Despite current guidelines for testing driver mutations in advanced nsNSCLC, a large segment of our patients are not being tested for those genetic aberrations. There are several barriers that continue to thwart the recommendation, including failure to integrate driver mutation testing into routine pathology practice (ie, reflex testing), insufficient tissue obtained from biopsy, and difficulty in obtaining tissue because of tumor location or risk of complications from the biopsy procedure. More important, these trends are not isolated to our institution and reflect a significant challenge within the oncology community. Our data show that for the purpose of driver mutation testing, larger-sample biopsies, such as surgical/core biopsies, are better than small-sample biopsies, such as needle aspiration. We have also demonstrated that the prevalence of driver mutations is lower in Western Pennsylvania, which is served by our network, than elsewhere in the United States.
