Complete Case – Dr Michaud – Case Study Transcript
Gaetane C. Michaud, MD
A Case-Based Pulmonology Perspective to Biomarker
Testing in Advanced NSCLC
Hello, my name is Dr. Gaetane Michaud. I’m the chief of interventional pulmonary medicine at NYU Langone Health in New York City. My area of focus in pulmonary medicine has been in thoracic oncology. For the last 15 years I have been managing patient complications from tumors in the lung, as well as doing diagnostics for patients that have either lung cancer or other cancers affecting the lungs. We’re going to talk today about a case of a 64-year-old man with stage 4 adenocarcinoma of the lung presenting with progressive dyspnea.
The symptoms failed to respond to two courses of antibiotics so he was referred to see a pulmonologist. The chest x-ray shows a lung mass and this was confirmed by CT scan that also showed mediastinal lymphadenopathy. The pulmonologist performed an endobronchial ultrasound-guided core biopsy of the mediastinal mass as well as the affected lymph nodes. And multiple specimens were collected including specimens for dedicated molecular characterization. Essentially what we do when we do these endobronchial ultrasound guided biopsies, we generally try to do core biopsies and the reason that we do is it has a higher volume of tissue. There’s been lots of studies back in sort of 20 years ago that looked at the difference between an FNA versus actually a core biopsy and what they showed is that there’s an increased yield using a larger bore needle and doing core biopsies. The reason for wanting to get additional tissue is also predicated on the fact that in this era of molecular testing a lot of patients are still being put into clinical trials and FNAs, for the most part, have actually been not allowed for clinical trial purpose. So approximately 10 years ago I stopped doing FNAs and started doing core biopsies. We use multiple, we take multiple specimens and the reason we take multiple specimens is because we actually like to have tissue for immunohistochemistry but also for molecular characterization. Generally my practice what I’ll do is I’ll take three to four specimens per site of biopsy for immunohistochemistry alone and then take additional samples that are dedicated for molecular characterization. The best study is actually by a group at Hopkins that actually looked at the number of specimens needed to be able to do both immunohistochemistry and then molecular characterization, which shows it takes approximately four samples per site to be able to do that.
We can also use rapid on-site sample evaluation and we certainly do that in our institution. What they do with this is they actually tell you about the cellularity and actually tell you whether or not your sample is adequate for molecular characterization.
So the patient went on to having additional imaging for staging, which included a PET/CT, which confirmed the CT scan findings but in addition, there was a single bone lesion in the 7th rib. We generally don’t use the rib or bones to actually do tissue analysis for diagnostics. The reason we don’t do that is because as part of the processing to demineralize the bone it makes it really difficult to do the molecular testing. Because of the issues with respect to biopsying brain or alternatively the demineralization of the bone we prefer to actually, in this case, biopsy both the lesion as well as the mediastinal lymphadenopathy. That said, the other thing is when you are biopsying the mediastinum and the primary lesion what we tell you to do is to actually biopsy the highest stage lesion first, meaning that if you’re going to biopsy the mass at the same setting what you want to do is you want to biopsy your mediastinal lymph nodes first and go from N3 to N2 to N1 and then finally the primary mass.
The other important factor is actually having that collaboration with your pathologist and knowing what tissue that they want because I think your best diagnostic yields and your best staging yields come from actually having that conversation. Sitting down with your pathologist and having a conversation, asking them how they want their tissue prepared because I’ve worked in multiple different centers and I can tell you that our preparation is different in each different site and my diagnostic yield when I change sites usually actually goes down for the first couple weeks and then after I have the conversation with the pathologist and prepare the tissue exactly as asked my diagnostic yields bounce right back up and I think that’s really important.
Many times what happens is that a site is biopsied or the primary tissue is biopsied but we don’t actually have adequate staging or alternatively we don’t have molecular analyses so we don’t have a comprehensive panel that can help guide treatment. So we see these patients in the office. They’re then presented at our multidisciplinary tumor board, which occurs for us on Friday mornings. In that group we have thoracic surgery, medical oncology, radiation oncology, pulmonary and in addition we have pathology and radiology. We review all new cases and we talk about not simply the diagnostic approach and the staging approach but also ongoing clinical trial inclusion as well as what our therapeutics are going to be. I’ve worked in the multidisciplinary system since approximately about 2000 and I think this is actually really to the advantage of the patients because they get the upfront evaluation of their case from all the many specialties that’ll be involved in their care.
I’d like to thank you for joining me in this case review and I hope that you found this video very informative.
CASE STUDY ON BIOMARKER TESTING IN ADVANCED NSCLC
Patient Case: Biomarker Testing in Advanced NSCLC