My friend has cancer of the throat and recently underwent surgery to remove the cancer? will he need radiation?

Depends: Location, nodal involvement and adequacy of resection will help to determine if he requires any additional treatment such as radiation therapy.

Short list.: Side effects include decreased saliva production, throat irritation and soreness with some discomfort on swallowing. Possible hoarse voice from vocal cord inflammation. These are from an oncologist's point of view; for more information contact your radiation therapist.