ASCO: Molecular Testing for All Lung Adenocarcinomas

Nick Mulcahy

October 13, 2014

A guideline that identifies which patients with lung cancer should be offered molecular testing has been endorsed by the American Society of Clinical Oncology (ASCO) and published online today in the Journal of Clinical Oncology.

The guidance was originally issued by the joint College of American Pathologists/International Association for the Study of Lung Cancer/Association for Molecular Pathologists.

Most notably, the guideline states that all patients with lung adenocarcinoma (or mixed lung cancers with an adenocarcinoma component) should undergo testing for epidermal growth factor receptor (EGFR) and anaplastic lymphoma kinase (ALK).

The testing should be done irrespective of characteristics such as sex, race, and smoking status.

"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 Dr Natasha Leighl, from the University of Toronto, Ontario, Canada, in a press statement. She is co-chair of ASCO's expert panel that endorsed the guideline.

EGRF-targeting drugs, such as erlotinib (Tarceva, Roche/Genentech) and afatinib (Gilotrif, Boehringer Ingelheim), and ALK-targeting drugs crizotinib (Xalkori, Pfizer) and ceritinib (Zykadia, Novartis) are effective only in patients with specific mutations in the related genes.

Clinicians should consider testing in patients with clinical criteria that are suggestive of the all-important EGFR mutations or ALK rearrangements, even if their tumor samples are not ideal.

"The guideline recommends that small tumor samples of other histologies, for which an adenocarcinoma component cannot be excluded because of sampling, can be considered for testing, particularly if clinical criteria are suggestive (eg, younger age, lack of smoking history)," write the ASCO authors.

The guideline also states that EGFR testing should detect mutations in samples composed of as few as 50% tumor cells. Sensitizing EGFR mutations with a population frequency of at least 1% should be reported.

The guidelines also outline what clinicians should expect from the labs that provide testing.

Laboratory turnaround times of 5 to 10 working days for EGFR and ALK results are recommended, with transport times of 3 days from day of request to an outside molecular facility and 24 hours within an institution.

The following are not recommended as predictive assays for treatment selection: immunohistochemistry for total EGFR, EGFR copy number, and ALK real-time polymerase chain reaction.

The guidance is likely to be updated sometime in the near future because there is new evidence regarding ALK testing; testing for molecular alterations associated with acquired resistance to EGFR and ALK inhibitors; new markers, such as ROS1, RET, ERBB2 (HER2), BRAF, and MET; and next-generation sequence testing.

Several members of the ASCO expert panel have ties to industry, including companies that make targeted therapies for lung cancer.

J Clin Oncol. Published online October 13, 2014. Abstract

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