Try to get an earlier appointment with your oncologist to talk all this over.
My sister in law had metastatic endometrial cancer, very advanced on diagnosis. Chemo got rid of all her distant metastases, just didn't shrink her primary. What I'm saying is...it may not have done what the surgeon hoped for, but it may have destroyed those strays. Surgery will be rid of the primary. Your oncologist may well have another plan in mind.
I can fully understand your devastation ar the news. We are here to listen. Kath x