Surgery for anorectal melanoma

Some people need a bigger operation to remove the cancer. Your doctor may suggest this operation if:

• you had a local excision but some cancer could not be removed or has come back
• the tumour is in a difficult area to remove with a local excision
• the tumour cannot be completely removed by a local excision, and involves structures in the anus or rectum that may cause a loss of bowel control (incontinence).

For an abdominoperineal resection, the surgeon removes all of the anus and rectum and a small part of your colon. They may also remove nearby lymph nodes if the cancer has spread there.

The surgeon closes the hole where the anus was. They make a cut on your abdomen (tummy) and join the end of your bowel to this opening. This is called a stoma or colostomy. Having a stoma means stools (poo) will no longer pass out of the rectum and anus in the usual way. Instead, they will pass out of the stoma into a disposable bag that is worn over it.

Being told you need a stoma can be distressing. Most people find they get used to the stoma over time. You will get support and advice from a stoma nurse in your hospital.

Some people have an anterior resection. This is when the surgeon removes the rectum. Sometimes the surgeon will also remove nearby lymph nodes. After the piece of bowel that contains the cancer is removed, the surgeon rejoins the two open ends of bowel. The first diagram shows the part of the bowel that is removed.

A diagram of anterior resection where part of the bowel has been removed

The second diagram shows how the two ends are joined together.

A diagram an anterior resection, where the two open ends of bowel have been joined together

Some people may have a temporary stoma after this operation. This is an opening that is made through the tummy (abdominal) wall and connects the bowel onto the surface of the tummy. Having a stoma means stools (poo) will no longer pass out of the rectum and anus in the usual way. Instead, they will pass out of the stoma into a disposable bag that is worn over it.

People with a temporary stoma will have a second, smaller operation a few months later. This second operation is to close the stoma and rejoin the bowel. It is called a stoma reversal.