Testicular cancer with metastatic lung cancer, after 4 rounds...

Of chemo the 5 original tumors in my lungs have reduced down to 4 with all of them dropping in size significantly except one. One tumor dropped from 23mm to 18mm and on recent PET scan shows its still active. All the other tumors show they are "cold". My oncologist is recommending surgery to remove that tumor rather than chemo. Ive never heard of this and Im trying to find out if this is common practice or if anyone that has had this form of cancer has gone through surgery rather than chemo to treat it.