Anal Cancer

Introduction

Cancer is where normal cells in the body change and start to reproduce in a non-controlled way, resulting in a tumour being formed. With anal cancer, it is the cells lining the anal canal which are affected. The anal canal is the final portion of the large bowel and is approximately 2-4cms in length, connecting the anal opening to the rectum above.

Anal cancer is uncommon in Australia - there are approximately 400 new diagnoses of anal cancer in Australia per year. Women account for more cases of anal cancer than men, and it is generally more prevalent in people aged over 50.

Symptoms

The following symptoms may be caused by anal cancer, however it is important to note that these symptoms may also be due to a number of other less serious conditions. In all cases it is advisable to see your doctor as soon as any of these symptoms develop to determine the exact cause.

Symptoms may include:

  • Bleeding from the anus.
  • Faecal incontinence.
  • Itchiness (in the area around the anus or in the groin).
  • Lump / growth (in the general area of the anus).
  • Pain / discomfort (in the area around the anus or in the groin).
  • Ulceration in / near the anus.

Types

There are two main types of cancer that can affect the anus. These are adenocarcinoma and squamous cell carcinoma. Other more rarer types of cancers around the anus include basal cell carcinoma, gastro-intestinal stromal tumour ('GIST'), lymphoma and melanoma.

Causes

The risk factors for developing anal cancer include:

  • Anal sex.
  • HIV / AIDS.
  • HPV (Human Papilloma Virus – specifically the cancer-causing strains which cause anal and genital warts).
  • Impaired immune system.
  • Smoking.

Tests & Diagnosis

A range of tests are used to determine the cause of symptoms and find out if anal cancer is present. These may include:

  • Reviewing the patient history and identifying risk factors, combined with a physical examination. This includes a digital rectal examination, checking for any lumps outside or inside the anus.
  • Anoscopy / Proctoscopy - these involve specialist instruments used to perform a visual check of the anus and rectum respectively.
  • Biopsy - a tissue sample, generally taken from the anus under anaesthetic.
  • Imaging tests such as MRI and/or PET scan. These are more commonly used once anal cancer has been diagnosed to determine the stage of the cancer.

Treatment

In general, anal cancers are treated with a combination of chemotherapy and radiotherapy. In certain circumstances where these treatments fail, surgery may be necessary.