Why is my oncologist sure it's cancer without biopsy results?

I fail about three months ago never had trouble with my hip till I fell. They found a lesion. They still know it says it’s unspecified they’ve done PET scan bloodwork and nothing is showing up so they’re doing a bone biopsy Monday. The oncologist is saying she sure is cancer. How can she really say that without the biopsy? None of my blood work are scans have shown anything but normal