lunes, 12 de marzo de 2012

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

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

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

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