Customize
Quick Links
Specialties

Physicians’ Education Resource®, LLC, is accredited by the Accreditation Council for Continuing Medical Education to provide continuing medical education for physicians. These activites are not approved for AMA PRA Category 1 Credit™

Acknowledgement of Commercial Support

This activity is supported by an educational grant from AstraZeneca.

Medical Crossfire®: Leveraging Liquid Biopsies in Tumor Characterization for NSCLC Therapy PER Pulse™: Recap

PER Pulse Recap

PER Pulse™ Recap



1 of 3

Clinical Data With Liquid Biopsies in Patients With Lung Cancer

Medical Crossfire®: Leveraging Liquid Biopsies in Tumor Characterization for NSCLC Therapy featured nationally recognized lung cancer experts. The program chair, Benjamin P. Levy, MD, along with faculty, Philip C. Mack, PhD, Sarah B. Goldberg, MD, MPH, and Geoffrey R. Oxnard, MD, PhD, discussed the scientific basis for liquid biopsies, the limitations of both tissue and liquid biopsies, and applications of liquid biopsies in the clinic.

This first of 3 PER Pulse™ Recaps from this Medical Crossfire® focuses on clinical experience with liquid biopsies.

  • A prospective study was carried out by Sacher et al. to investigate the sensitivity, specificity, and turnaround time of plasma-based testing and tissue-based testing. The sensitivity of plasma-based testing compared with tissue-based testing correlated with the number of sites of metastasis, ranging from approximately 60% with 1 site to nearly 100% with ≥4 sites. The specificity for epidermal growth factor receptor (EGFR) exon 19 and L858R mutations was 100%. Turnaround time was much more rapid for plasma-based testing, with a median turnaround time of 3 business days, compared with 12-27 days for tissue-based testing.
  • Oxnard et al. carried out a comparison of plasma- and tissue-based testing for the EGFR T790M resistance mutation. In the case of a positive plasma result, the overall response rate (ORR) was 63% with osimertinib, similar to that of patients with tissue-positive T790M (62%). However, patients with tissue-negative results had an ORR of 26% with osimertinib, compared to 46% with plasma-negative results, suggesting the presence of false negatives with plasma-based testing, and the need to verify these results with tissue-based testing.


2 of 3
PER Pulse™ Recap

Interpretation of Results from Liquid-Based Molecular Testing

Medical Crossfire®: Leveraging Liquid Biopsies in Tumor Characterization for NSCLC Therapy featured nationally recognized lung cancer experts. The program chair, Benjamin P. Levy, MD, along with faculty, Philip C. Mack, PhD, Sarah B. Goldberg, MD, MPH, and Geoffrey R. Oxnard, MD, PhD, discussed the scientific basis for liquid biopsies, the limitations of both tissue and liquid biopsies, and applications of liquid biopsies in the clinic.

This second of 3 PER Pulse™ Recaps from this Medical Crossfire® focuses on interpretation of next-generation molecular testing results with liquid biopsies.

  • The first case involved a patient with lung cancer and a mutation in the epidermal growth factor receptor (EGFR) gene and acquired resistance to first-line EGFR tyrosine kinase inhibitor therapy. The results showed a 32.2% allele frequency for the original EGFR-L858R mutation. The results also showed T790M with a frequency of 1.8%. These results were discussed as showing the importance of seeing the original driver mutation to believe the detection of T790M; 32.2% was considered high and indicative of an aggressive tumor. For T790M, 1.8% was considered a positive result, however, the proportion was small, so T790M may not be the dominant resistance mechanism.
  • The second case involved a patient who had undergone tissue-based testing, which was negative for oncogenic drivers. The patient was started on chemotherapy; a second biopsy resulted in insufficient tissue for testing. After progression on chemotherapy, plasma-based testing was carried out, showing the presence of an anaplastic lymphoma kinase (ALK) gene rearrangement, with a frequency of 0.9%. It was pointed out that the median for plasma analysis is approximately 0.5%, to indicate that this would be considered positive for ALK. Additionally, an allele frequency of 0.9% does not mean that 99% of the tumor does not have the oncogenic driver; the frequency has to do with the kinetics of cell-free DNA being released, and is affected by several factors, including aggressiveness of the tumor and disease burden.
  • In the third case, the presence of P53 as a positive control was discussed. The results in this case did not show any oncogenic driver, but the frequency of P53 was only 0.1%, suggesting a low level of sensitivity of the test, and that tissue-based testing should be done to verify the lack of an oncogenic driver.

3 of 3
PER Pulse™ Recap

Current Applications of Liquid-Based Molecular Testing

Medical Crossfire®: Leveraging Liquid Biopsies in Tumor Characterization for NSCLC Therapy featured nationally recognized lung cancer experts. The program chair, Benjamin P. Levy, MD, along with faculty, Philip C. Mack, PhD, Sarah B. Goldberg, MD, MPH, and Geoffrey R. Oxnard, MD, PhD, discussed the scientific basis for liquid biopsies, the limitations of both tissue and liquid biopsies, and applications of liquid biopsies in the clinic.

This third of 3 PER Pulse™ Recaps from this Medical Crossfire® focuses on the current applications for liquid biopsies.

  • Acquired resistance to targeted therapy
    • A tissue-based biopsy is the standard; if tissue is not available, plasma-based testing is reasonable.
    • However, the experts thought that plasma-based testing could also be used as a test before tissue biopsy.
    • If a patient is experiencing rapid progression, arranging for both plasma- and tissue-based testing would allow for the ability to most quickly choose subsequent therapy.
  • Treatment-naïve setting
    • Liquid biopsies are currently not sufficient for lung cancer diagnosis; tissue is still needed.
    • However, after diagnosis, if there is inadequate tissue for molecular testing, then liquid-based testing is reasonable; in this case, plasma should be collected before starting chemotherapy.
PER® Practice Pulse
Practice Pattern Questions
How often do you attend society oncology/hematology meetings? (ASCO, ASH, SABCS)
Practice Pattern Questions
What is the most significant barrier to implementing new information in your clinical practice?






Become a Member

Forgot Password?
Calendar of Events
SUNMONTUESWEDTHURSFRISAT
     12
3456789
10111213141516
17181920212223
24252627282930
31
Filter By