How Molecular Test Results and Delays Influence Treatment in NSCLC


During a Case-Based Roundtable® event, Julia Rotow, MD, continued a discussion on how biomarker testing for patients with non–small cell lung cancer impacts treatment decisions in the second article of a 2-part series.


  • How often do you receive a report on PD-L1 status prior to all remaining biomarkers?​
  • Do you initiate therapy before all results are returned?​
  • Do you read the entire molecular test report or review specific results?

JULIA ROTOW, MD: When you get your test results back, are you usually getting PD-L1 results much quicker, [in comparison]? I feel like I often have that back right away, and I don't have my next-generation sequencing for a while. Is that something [you all are] encountering as well?

Julia Rotow, MD

Julia Rotow, MD

Clinical Director, Lowe Center for Thoracic Oncology

Dana-Farber Cancer Institute

Assistant Professor of Medicine

Harvard Medical School

Boston, MA

KONSTANTINOS ARNAOUTAKIS, MD: Yes, PD-L1 usually comes back much more quickly than the molecular testing.

ROTOW: The big question, and the one that we all face, is how often do you find that you need to start systemic therapy before having all the test results back? Does that come up often? How do you handle that situation when it happens?

I'll say I encounter [this scenario]. I think we see sick patients who just can't wait to start therapy or the patient with the insufficient biopsy sample who needs a new biopsy, and it's going to be a month [before the test comes back]. We encounter these patients [and need to treat them quickly].

DAVID CHISM, MD: I would say [I encounter this scenario] at least 15% of the time, and sometimes I just put these patients on systemic treatment, wait for the results of the tests, and see how we're doing at that point. When I meet the patient, I tell them that this [long wait] could be a possibility in these cases.

ROTOW: If you do start systemic therapy for [patients with] adenocarcinoma, what's your go-to [therapy] in that situation?

CHISM: Certainly, pemetrexed, platinum chemotherapy, and then pembrolizumab [Keytruda].

ROTOW: Does anyone else find themselves starting that as a stopgap therapy?

RYAN CARR, MD: If I don't have [the molecular tests] back, and I'm suspicious that the patient may have an EGFR mutation, then I hold pembrolizumab for the first cycle and then switch over if it's a low chance of being positive.

ROTOW: Do you read the entire test report or use specific results? That feels like a judgmental question, and I suppose it's getting at [if] you are looking at those tier-1 mutations? I don't know how far people are getting down in the report when they're reviewing them.

ARNAOUTAKIS: I read the report and I read what they tell us about the genes, and sometimes I'll research the genes myself, because sometimes the [FoundationOne CDxTM test] description doesn't even apply to the to the mutation they are reporting; they're just giving us generic [information].


  • What would you offer a patient with non–small cell lung cancer positive for a ROS1 mutation?

NATALIE M. SPRADLIN, MD: I would choose entrectinib [Rozlytrek]. It is familiar and comfortable, and it's good to have the knowledge that I still have repotrectinib [Augtyro] in my back pocket, if and when they progress, because I would not feel nearly as comfortable going to crizotinib [Xalkori]. So, it's mainly to just play that game of chess and try to still have something that's effective available for use rather than going backwards.

ROTOW: Fair enough, so you're saving something for second-line treatment. I understand that perspective and I think it speaks to the variability of what’s used in the frontline setting.

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