2 doctors that my boyfriend consulted with told him that portal vein blockage would eliminate the use of chemoembolization, others said the same about radioembolization (theraspheres and sirspheres) At the Mayo Clinic, they recommended both for him.
Ultimately he went with a leading intervention radiologist at John's Hopkins, Dr. Geschwind who debunked this opinion, stating that this has been done for years and that it is an old notion that this procedure cannot be done with portal vein thrombosis.
A catheter is run from the femoral artery at the hip up to the liver or site of the tumor, from there I don't know the exact mechanics just that the radiologist will find entryways into the tumor to administer the chemo...
If you would like further information about to expect, I can provide you with more details. My boyfriend had 2 of these procedures done at Johns Hopkins.