One Nurse's Perspective

How Has Genetic Testing Changed Treatment Approaches for Patients With Lung Cancer?

Leslie B. Tyson, MS, ANP-BC, is a clinical research nurse practitioner on the thoracic oncology service at Memorial Sloan-Kettering Cancer Center in New York, NY.

In the past, patients with lung cancer were diagnosed primarily as having either non-small cell lung cancer (NSCLC) or small cell lung cancer (SCLC). As NSCLC subtypes, squamous cell and adenocarcinoma were treated as if they were the same disease. We now know that’s no longer true and that these cancers respond differently.

Studies have shown that patients with nonsquamous NSCLC have better responses with pemetrexed compared to those with squamous cell lung cancer. In fact, premetrexed is approved for use in those with nonsquamous NSCLC as opposed to NSCLC in general. Bevacizumab is also used only in nonsquamous NSCLC, because patients with squamous cell lung cancers were shown to have a higher risk of hemorrhage.
All new patients with lung cancer who come to us have their tumor automatically tested for cytogenetics and diagnostic molecular pathology. Even before biomarker testing, general patient characteristics would indicate better response rates to EGFR TKIs, such as Asian ethnicity, nonsmokers, and adenocarcinoma. Now, testing for EGFR and KRAS has a tremendous impact on an individual’s treatment, because identifying these mutations helps clinicians select treatment for lung cancer. Patients with EGFR mutations are often given erlotinib as part of initial therapy. Those with tumors that have KRAS mutations are naturally resistant to EGFR targeted therapy and are therefore given platinum-based chemotherapy.

One of the newer biomarkers in patients with lung cancer is EML4-ALK. It is a gene rearrangement seen most commonly in younger, never or light smokers and men more than women. It was originally discovered in 2007, and a drug, crozitinib, is already available to target this mutation. We’ve seen some remarkable responses, so naturally everyone’s excited.

We still meet patients who have not been tested when they come to us. Sometimes the appropriate testing is not always available in some communities. The old notion that testing for these mutations isn’t important because all of the subtypes of NSCLC are essentially the same disease still exists. And sometimes it can require real effort to properly identify mutations when patients have been diagnosed exclusively through cytology findings. In the end, identifying these mutations can make a world of difference in treatment outcomes.

—As reported to Contributing Editor Heather McCreery, RN, MBA, OCN^®, CCRC