If there is any overlap in characteristics between ductal and interductal PC (and I really mean IF! Because I don't know! But Dr. WHO sort of suggests this above), then the reason pwallace's doctor correspondents suggested genomic testing may be this:/www.ncbi.nlm.nih.gov/pmc/articles/PMC5347709/
In a small sample (10), 4 patients with ductal PC had a DNA mismatch repair mutation. DNA mismatch repair mutation with advanced (and advancing on treatment) PC is FDA approved for Keytruda.
So if those (rare) genetic markers are way more common in ductal PC, at least for that, there is a potentially large treatment impact. See my .signature.
There are many caveats about
this, but at least do talk to your doctors. Especially if you are getting a biopsy on something other than bone! Because the testing would need to be done on that.