Disclaimer: I don't know what I'm talking about.
I would think if you told them you wanted the cash pay price, you should be able to get it done easily on your own dime. You have to pay it in full, upfront. That's what a friend does when he doesn't want to run stuff (like a colonoscopy) through his insurance ... because when he mentions insurance, the amount he ends up paying towards the deductible is much higher than the cash price without insurance. It might work for a second opinion.
Reread Disclaimer at the top
Nov-2009 Early stage CRC found during routine colonoscopy
2010, 2011, 2014 Follow up colonoscopies, all clear
Jun-2016 CRC found during routine follow up colonoscopy, surgery, Stage 4, KRAS, inoperable lung mets
Aug-2016-May-2018 Folfox, 5FU & Avastin, 5FU, Folfiri & Cyramza
Aug/Sep-2018 YAG laser surgeries (Germany) on both lungs, 11 nodules (9 mets) removed
Oct-2018 ... holding pattern