what exactly is fistula
A fistula is an abnormal opening or channel that joins two or more structures or spaces within the body. For example, a fistula can develop between two organs of the body, such as the bowel and the bladder, or the bowel and the skin.A cancer fistula is rare. It develops because of cancer or its treatment. If it is caused by cancer treatment, itâs often a late side-effect and may take many months or years to develop.istulas are more common in the pelvic area. Fistulas are a rare side effect of cancer treatment. They can also develop as the result of a cancer growing. Symptoms of a fistula depend on where it is in the body. Common symptoms include: 1  leaking urine through the vagina or back passage.