opinion on treatment of both colon and breast cancer

[Ger57]

My sister was diagnosed with colon cancer with small metastasis on liver. The colon cancer is surgically removed and the plan was to remove the liver metastasis also surgically. No further treatment would be necessary.

To be sure that no other metastases were overseen, a PET scan was done. Besides the liver metastasis, some activity was seen in the breast area. Biopsy revealed breast cancer with a positive lymph node in the armpit.

A liver puncture is performed to determine the origin of this metastasis (colon or breast), results not yet known.

It seems that the doctors want to treat the breast cancer first and leave the colon metastasis on the liver for now, while I think that, when the metastasis is removed, my sister is facing "only" a breast cancer battle.

Please share your ideas on this sad topic.

[Ger57]

Please share your thoughts on this sad topic for both the scenarios:
1- liver metastasis is colon cancer
2- liver metastasis is breast cancer