Facts and figures about anal cancer
Anal cancer is rare, approximately 1,200 new cases each year in the UK which accounts for about 0.4% of all new cancer cases. Higher incidence in women, male to female ratio is approximately 10:18.
Age related, incidence rises sharply from the 35 years, approximately 50% diagnosed in those over 65 years and an average of 25% of cases are in the 75+ years age group.
Majority of them are squamous cell carcinomas with a very small number of adenocarcinomas which behave differently and therefore should be treated like rectal cancers. Risk factors include HPV infection (90% are linked to HPV infection), multiple sexual partners, anal intercourse, genital warts and previous cancer of the cervix, vaginal or vulva, smoking and HIV infection.
Anal cancer symptoms
- 20% of patients have no symptoms at diagnosis.
- Rectal bleeding – often ascribed to haemorrhoids, subsequently diagnosis can be delayed.
- Small lumps around the anus- often ascribed to haemorrhoids.
- Ulcers around the anus.
- Pain, discomfort or itching in the area.
- Passing mucus from the rectum.
Diagnosis of anal cancer
Investigations may include:
- Physical examination (including internal examination).
- Anoscopy – tissue samples may be taken for analysis.
- Endo-anal or endo-rectal ultra sound.
- CT scan.
- PET scan.
- MRI scan.
Anal cancer treatment
Depends on several factors:
- The type of tumour.
- The position of the tumour.
- The stage of the cancer.
- General health.
Surgery is not often used for anal cancer now, the preferential treatment being a combination of radiotherapy and chemotherapy. Occasionally used for small tumours if the chemoradiation hasn’t cleared the disease. This may be a local resection removing small tumours on the outside of the anus (if this is the initial treatment, chemoradiation may be recommended after surgery).
In some cases, more extensive surgery may be recommended and this involves the removal of the anus and rectum (abdominoperineal resection), which will require a permanent colostomy.
Radiotherapy in combination with chemotherapy is usually the main treatment for anal cancer as it can be effective and avoids major surgery.
Intensity Modulated Radiotherapy (IMRT) is now being used in some radiotherapy centres and in some cases of anal cancer is proving to increase the effectiveness of treatment by enabling the disease to be targeted very accurately hence reducing dose to healthy tissue and reducing side effects.
Image guided radiotherapy (IGRT) also enables the radiotherapy to be precisely delivered to the intended area which reduces potential radiation dose to healthy tissues by allowing the radiography team to review organ position and ideally adapt the patient position on a daily basis to ensure precision.
Chemoradiation will also treat disease that has grown into nearby tissues and lymph nodes. Palliative radiotherapy may be given to try and shrink the tumour to relieve symptoms.
Chemotherapy is used with radiotherapy (chemoradiation). The chemotherapy drugs are usually fluorouracil (5FU) and mitomycin C. Chemotherapy may be given if the disease has recurred in other parts of the body to help control and relieve symptoms.