I saw the pulmonologist today and he indicated that the 4mm lung lesion was too small to be biopsied successfully with a needle biopsy. He called the interventional radiologist, who agreed with this assessment. The pulmonologist thought that the 4mm lesion didn't look like lung cancer, which means it might be either metastatic breast cancer or another cancer (like colon) that metastasizes to the lungs. He also thought that doing another kind of biopsy would mean removing more lung than would be necessary at this time.
These docs would like me to have a PET scan, and if this lesion lights up, we would consider treating it as metastatic breast cancer, then re-scan. And if it doesn't light up, do another CT scan in 2 months. The pulmonolgist will call my oncologist and fill him in. I hope Dr. G will agree with this assessment!
So for now I am canceling the appointment with the thoracic surgeon scheduled for tomorrow, and waiting to get a call about setting up the PET scan. At least this way I can travel at a moment's notice if needed.