In response to @stayfaithful, yesterday was my first consultation with the oncology team regarding the CT and MRI scans that they did.
Operating "could" be done, but since it is stage 4 (rectal tumor, liver, pancreas and other spots) surgery is not a good option. Surgery, as explained to me, would not be a "cure" whose benefits might be none or marginal - meaning that I would undergo a grueling and major disruption to my life with no promise of a benefit.
It sounds like your oncology team leader came to the same conclusion but without telling you so (or perhaps they did but you missed it under the avalanche of other information).

My onc team now want to biopsy the liver and pancreas to learn more about the cancers - the data will tell them which known therapies are most likely to be successful. Currently, the MRI/CT "shadows" on the liver and pancreas are mysterious but indicative of tumors.

So. . .it's into the machinery of modern healthcare I go. The unwanted adventure begins!