Anne S. Tsao, MD, begins the conversation regarding molecular testing results in non-small cell lung cancer (NSCLC) by stating that current guidelines suggest that 2-3 weeks is an acceptable time to wait for test results. However, if results are not available at 2 weeks and a patients is symptomatic, Tsao adapts the guidelines and will begin treatment with chemotherapy.

For patients with oncogene-driven NSCLC following progression, Mark A. Socinski, MD, is an advocate for rebiopsying a tumor for the loss of a mutation or a possible acquired mutation, such as T790M. Corey J. Langer, MD, agrees and notes that following progression some patients wtih EGFR mutations may emerge with small cell histology, which dramatically changes their treatment options. However, Langer notes, the decision to rebiospy should be affected by the patient's access and willingness to participate in clinical trials.

To advance the field, Tsao believes that it is important to realize that not all lung cancers are the same and that rebiopsying should be emphasized. Socinski agrees, to an extent, by saying that rebiopsying should be done as a part of clinical trials that explore novel drugs in new or molecularly-defined populations. Tsao agrees, and notes that rebiopsying should be crucial since promising second generation targeted agents may be available in clinical trials.

Gandara closes by pointing out that research has shown that over 50% of patients test negative for the EML4-ALK fusion in a rebiopsy following progression on crizotinib. For these patients, a rebiopsy will dramatically alter their treatment and may even indicate an acquired EGFR mutation.