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Lung guideline goals: more tests, treatment

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Karen Titus

March 2018—Among the many never-ending chores that humans undertake—paying bills, filing taxes, flossing—writing medical guidelines can seem like an especially perpetual task. Just ask the architects of an updated document on molecular testing for lung cancer, issued by the CAP, the International Association for the Study of Lung Cancer, and the Association for Molecular Pathology.

How empowering to produce a hefty, 18-statement-strong work (plus three specific changes to the previous guideline), aimed at selecting patients for treatment with targeted tyrosine kinase inhibitors (Lindeman NI, Cagle PT, Aisner DL, et al. Arch Pathol Lab Med. Published online ahead of print Jan. 22, 2018. doi:10.5858/arpa.2017-0388-CP).

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For lung cancer molecular biomarker testing, cell blocks were recommended over smear preparations in the 2013 guideline. The new guideline says any cytology sample with adequate cellularity and preservation can be tested. “We’re going to see significant patient benefit,” Dr. Dara Aisner (right) says of the change.

And how fatiguing to realize, even as the guideline neared completion, that compelling new research was already knocking at the door.

“One of the challenges in a systematic review process is that the information comes faster than you can establish the systematic review process,” says coauthor Dara Aisner, MD, PhD, associate professor, Department of Pathology, and director, Colorado Molecular Correlates Laboratory, University of Colorado School of Medicine, Aurora.

That’s not to say the guideline is deficient. Rather, the guideline reflects molecular testing in all its complexity and importance, says coauthor Philip Cagle, MD. “Just because something is newly described” doesn’t mean it’s earned guideline status, no matter how promising. “This is intended to assist physicians, their patients, and their families in selecting the best and most up-to-date treatment with these inhibitors. We don’t want to endorse something that may not pan out,” says Dr. Cagle, director of pulmonary pathology and professor, Department of Pathology and Genomic Medicine, Houston Methodist Hospital, and professor of pathology and laboratory medicine, Weill Cornell Medical College, New York.

It also serves as a welcome update to the previous guideline, published in 2013 (and a massive undertaking in its own right). The latest iteration doesn’t so much change the tenor of discussions as it addresses advances and technical knowledge that have emerged in recent years, says lead author Neal Lindeman, MD.

But he already spies areas where updates are likely to be needed. There is no rest for the weary. As the Almighty told ancient followers stamping their feet impatiently at the edge of the Promised Land, arrival brings both a blessing and a curse.

Among the new arrivals in this latest guideline is ROS1 testing, which joins EGFR and ALK as routine testing in lung adenocarcinoma cases. Testing for all three mutations must be performed on all patients, regardless of clinical characteristics.

“That’s probably the No. 1 change,” says Dr. Lindeman, associate professor of pathology, Harvard Medical School, and director, Center for Advanced Molecular Diagnostics, Brigham and Women’s Hospital.

A second highlight, he says, is the recognition that immunohistochemistry can be used as an alternative to FISH for testing ALK. The previous guideline recommended FISH; at the time, the ALK FISH break-apart assay was the only one supported by prospective studies.

Equally noteworthy is the guideline’s endorsement of multiplex-based approaches to testing. Though it’s not a requirement, the winds are noticeably shifting in that direction.

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