Molecular testing is central to the management of many cancers. We measured the extent to which FDA-approved and lab-developed tests (LDTs) are used in stage IV adenocarcinoma non-small cell lung cancer (NSCLC) patients, with a focus on EGFR mutations and ALKrearrangements.
A retrospective chart review of NSCLC patients was conducted between April and September of 2015. A representative sample of US oncologists was asked to complete an online form containing fields for anonymized patient information, including year of diagnosis, whether molecular testing was performed, and if so, which markers were tested, type of test used, and test location. 8,129 NSCLC-treating oncologists in the US were invited to participate in the study. Oncologists were eligible to participate if they personally managed at least 5 NSCLC patients per month, and diagnosed at least one NSCLC patients in the past 12 months
Information on 765 patient records was obtained from the 153 physicians who met eligibility criteria. Histological subtype split was as follows: 76% of patients had adenocarcinoma, 19% had squamous cell carcinoma and 5% had other types. Among the 579 patients with adenocarcinoma, 95% and 84% were tested for EGFR mutations and ALK-rearrangements, respectively. Sample was further reduced to only include patients for which the type of test was known, and whose diagnostic was performed after FDA approval of the relevant test (May 14, 2013 for EGFR and August 26, 2011 for ALK), resulting in 424 patients for EGFR, and 399 for ALK. 87% of adenocarcinoma patients were tested with non-FDA-approved tests for EGFR, and 49% for ALK.
This study highlights the prevalence of non-FDA-approved testing in the treatment of lung cancer. Further evaluation of the comparability of approved and unapproved tests currently being used interchangeably is needed to mitigate uncharacterized variability between tests.