Is it possible for an oncologist to need only inspect one lymph node to see if cancer has spread?

Yes: When a patient presents with signs suggesting malignancy and there are a cluster of serveral large, somewhat firm lymph glands then a selective biopsy has a high incidence of detecting an existing pathologic process. A core bx is better than aspiration but with a question, excision is best utilized for dx. If the bx neg. in some cases a bx of a second node would be indicated.