ASCO Endorses Lung Cancer Guidelines for Molecular Testing

ASCO has endorsed a clinical practice guideline from several associations on when to offer molecular testing for EGFR and ALK mutations in lung cancer patients.

The American Society of Clinical Oncology (ASCO) has endorsed a clinical practice guideline from several other professional associations aimed at guiding decisions on when to offer molecular testing for epidermal growth factor (EGFR) and anaplastic lymphoma kinase (ALK) mutations in patients with non–small-cell lung cancer (NSCLC). Research on drugs targeting some of these mutations has exploded in recent years, and clinicians in practice may have had trouble keeping up with when exactly testing should be done in order to guide use of those new therapies.

“This guideline is incredibly important, as it increases the ability to personalize lung cancer care and improve outcomes for patients with advanced lung cancer,” said Natasha B. Leighl, MD, co-chair of ASCO’s panel that endorsed the new guideline, in a press release. “It describes the current evidence and helps oncologists and pathologists understand and put molecular testing into clinical practice.”

The guideline is a joint product of the College of American Pathologists, the International Association for the Study of Lung Cancer, and the Association for Molecular Pathology. It contains 37 distinct recommendations, opinions, or suggestions, focusing on when to test for EGFR and ALK mutations; it was published on October 13 online in the Journal of Clinical Oncology.

The primary recommendation is to offer EGFR and ALK testing to all patients with lung adenocarcinoma (or mixed lung cancers with an adenocarcinoma component), regardless of characteristics such as smoking status, gender, or race. Small tumor samples of other histologies could be considered for testing, particularly if “clinical criteria are suggestive”-this would include younger age, and a lack of smoking history, among other factors.

The guidelines also contain instruction on specifics of the testing process. For example, EGFR testing should be restricted to detecting mutations in samples composed of at least 50% tumor cells, though a test with sensitivity to detect mutations down to as low as 10% tumor cells is “strongly encouraged.” Certain tests, including immunohistochemistry for total EGFR, EGFR copy number, and ALK real-time PCR are not recommended tests.

Molecular testing has rapidly become an important step in the treatment of patients with NSCLC. Drugs such as erlotinib and afatinib for EGFR mutations, and crizotinib and ceritinib for ALK mutation-positive patients, are becoming much more widely used, and clearly the molecular details of a patient’s disease are crucial in order to put these agents to best use.

The panel members concluded that this guideline represents a “great advance toward standardization of testing for EGFR and ALK alterations.” They noted, however, that even more recent work is starting to identify yet other possible targets, such as RET and ROS1 rearrangements, and subsequent research and guidelines will likely need to incorporate those as well.