Does a person always need a colostomy bag after colon cancer and if not why not ? thanks all

No,: it depends on the size, extent, and location of the tumor and other clinical factors. Sometimes a primary re anastomosis can be performed, where the 2 ends of the colon are reconnected following resection of the diseased part.

No. It depends on: several factors such as the location of the cancer in the colon, the size and spread of the tumor, etc.