If the oncologist says biopsy results show no cancer would it be smart to get a 2nd opinion just like someone would get if one had biopsy and cancer?

SECOND OPINION: That is always your perogative. I notice you have posted several questions regarding cancer treatment and spilling cells into blood, etc? Do you have an anxiety disorder? I am suspicious that this may be playing a role especially since you never mention what the tumor was and where it was. Did you have a history of cancer in past? why are you seeing an oncologist? There is a lot missing from this.