CT v PETScan

Hi Tkoss, lots of factors including cost come into play for PET-Ct vs just Ct scans. If you are 3c and have had all melanoma removed at SLNB and are presently NED and on Opdivo then for most patients scans would come every 3 months and usually just a CT scan. If they find something on images then a PET might be order to see how much SUV uptake or how active the tumor is. During my trial on checkmate 067 I had Ct scan every 6 weeks for first year and a half but that was in a trial and I was a partial responder with visible tumor on lung on ct scans so they were watching me closely. One thing to consider is the fact that not that long ago at 3c opdivo would not have been an option and many patients would have been in watch and scan mode. The MSLT-2 trial that looked at follow up after CLND used ultra sound to scan the lymph node basin, so by comparison to have Ct vs PET-Ct is a giant step forward in follow up. Something to consider is MRI of brain since we now know based on research coming out of MD Anderson, looking at 2000 patients in US and Australia, that risk of developing brain mets while on adjuvant treatment has higher chance based on specific factors like age, gender, mitotic rate and location of primary tumor, depth of primary, see following video from Dr. Michael Davies of MD Anderson from yesterday. https://www.facebook.com/MDAMelanomaMedicalOncology/videos/180389743368950/ https://ascopubs.org/doi/full/10.1200/JCO.19.01508

As Ed described, the CT is the normal standard of care for evaluation of the chest and abdomen. The other consideration is that a PET scan uses a radioactive tracer agent, and so exposes you to significantly more radiation than a CT (which is essentially a series of X-rays that are reconstructed by a computer into a 3D image).

My doctor had been ordering only CT scans, and we could see the tumours shrinking on those. Only the size shows, though. Now she wants me to have a PET scan to see how active (or hopefully not active!) the leftovers are. It could just be dead tissue. CT scans wouldn’t show that.