A cat scan of abdomen found that i have an enlarged prostate measuring 4.9 cm in traverse axis. should i be concerned about this? any treatment needed?

Depends....: It’s enlarged but concerns depends on family history , your symptoms and other laboratory testing as PSA. Reason you had CT ? Many times CT can show “ coincidental findings “ which would otherwise not be found nor be concern . Consult with your doc in view of you history and current health status . Maintain annual exam and healthy lifestyle, exercise , avoid smoking .