Anne Tsao, MD: I’m of the belief that all patients should be tested for next-generation sequencing. A large part of this though is due to the fact that we need to learn more about patients’ tumors. Right now for standard of care, we strictly look at genetic sequencing. Most of these tests are occurring in our adenocarcinoma patients. Some, in our never smoking squamous cell, and of course, we look for PD-L1 [programmed death-ligand 1], but that’s an immunohistochemistry marker.
There are definitely challenges to doing next-generation sequencing from the tumor tissue. Obviously, you have to have a very good biopsy. And oftentimes even when you have a good biopsy, you may not be able to extract enough tumor DNA to do the full next-generation sequencing panel, as well as doing the PD-L1, which you need.
Tumor tissue next-generation sequencing can be pricey, and you have to have enough tumor DNA. There are a lot of groups that are now looking at doing profiling from the plasma, and so that may certainly be a cost-effective measure to consider if your patient doesn’t have adequate tumor DNA to do this sort of sequencing.
Benjamin Levy, MD: When we order next-generation sequencing we have to be patient, which is very difficult for us who treat patients with non—small cell lung cancer. The turnaround time, depending on the platform used, can be anywhere from 2 to 4 to even 6 weeks. So we are waiting sometimes for this result to come back, and there are a lot of questions on what you should do. I would say if a patient is asymptomatic, that we should err on the side of caution and wait for that test to come back before we make a decision. However, if a patient is symptomatic and needs to start on treatment, I would start them on a treatment with chemotherapy, and then of course switch them to targeted therapy if we identified a specific genotype. So to me the decision on turnaround time and when to start is, if the patient’s really symptomatic, go ahead and start them on treatment. If they’re not, wait for that test to come back, but it can take up to 4 weeks in some centers to get those results back.
Anne Tsao, MD: Next-generation sequencing in the tumor tissue can take sometimes up to 3 to 4 weeks if you factor in the time it takes to do a good biopsy, and then to get the tumor tissue over from the pathology laboratory to perhaps the molecular pathology lab. So this can certainly be challenging for your patients who have to get started on treatment quickly.