Anal cancer is one of the rarest forms of cancer that occurs in the anal canal. About half of the anal cancers are fortunately diagnosed before the malignancy has spread beyond the primary side, i.e. the anus. About 13% to 25% of anal cancers are detected after the malignancy has reached lymph nodes and about 10% when it has reached to distant organs. The sooner is the diagnosis made; greater is the possibility of successful treatment.
The most common symptoms of anal cancer include-
- Formation of a lump near the anus
- Mucus discharge from anus
- Pressure or pain in the anal area
- Changes in bowel movements such as constipation, diarrhoea, etc.
- Anal bleeding
- Back pain (in women) due to pressure exerted on the vagina by the tumour
- Vaginal dryness
Irritation around the anal area can also be a symptom of anal cancer. However, many people mistake it for a symptom of haemorrhoids which leads to delay in cancer diagnosis.
Causes and Risk Factors
One of the most common causes of anal cancer is prolonged receptive anal intercourse. Hence, it has also been found that MSMs (men who have sex with men) are 20 times more likely to have anal cancer. Other causes of anal cancer include-
Smoking- Smokers are much more vulnerable to anal cancer in comparison to the non-smokers. In fact, smoking can give rise to the odds of developing many other types of cancer as well.
Age- Greater is the age of a person, greater are the chances of him or her developing anal cancer. However, age is directly proportional to the development of other cancers as well.
Weak Immune System- People who have a weak immune system are at a greater risk for developing anal cancer. This includes people who have had transplants, are diagnosed with HIV, or are taking immunosuppressant medications.
Other Cancers- Men who have had penile cancer and women who have had cervical or vaginal cancer are at a higher risk of attaining anal cancer.
Human Papilloma Virus (HPV)- Many types of HPV are closely related to the development of anal cancer. In fact, about 80% of the people diagnosed with anal cancer also have infection in their anal area with the HPV.
Number of Sexual Partners- People who have multiple sexual partners are more likely to develop anal cancer in comparison to those who have one or few sexual partners. This is because with more sexual partners the chances of being infected with HPV are higher, and hence are those of anal cancer.
The diagnosis for anal cancer generally starts with the patient seeing a general practitioner/ primary care physician. He will ask the patient about the symptoms and will perform a physical examination accordingly. He might also want to know about the patient’s medical history. After the check-up the patient is usually referred to a colorectal surgeon (a doctor who holds expertise in bowel related problems). The colorectal surgeon, who is also called a proctologist, then carries out the following tests:
Rectal Examination- A rectal examination may be discomforting to a patient, but it’s not painful. For this test a proctoscope is generally used, which is an instrument used by a doctor to examine the rectal area in more detail. This examination helps the doctor in deciding whether a biopsy is required.
Biopsy- In this test the doctor takes a small sample of tissue from the anal region and sends it to the lab for testing. At the lab the tissue is closely examined under a microscope.
If the result of biopsy comes out to be positive, i.e. if the same tissue is found to be cancerous then further tests are done to find out whether the cancer has spread, and if it has then to how much extent. These tests include –
Ultrasound Scan- In this scan sound waves are used to create an image of the target area. Instead of regular ultrasound the doctor may suggest a rectal ultrasound, in which the instrument is inserted into the anus to scan the target area.
MRI (Magnetic Resonance Imaging) Scan- In this scan various 2-D and 3-D pictures of the target area are taken with the help of radio and magnet waves.
CT (Computerized Tomography) Scan- In this scan x-rays are used to create a 3-D picture of the target area.
Depending on the severity of the tumour and the overall health of the patient the doctor may suggest a particular treatment from many. If the tumour is small then it could be easily removed with a surgery. A combination of radiotherapy and chemotherapy is also often used for the treatment of anal cancer.
One can prevent the development of anal cancer by reducing the chances of getting infected with HPV. Other than this, limiting the sexual partners and avoiding anal sexual intercourse can also be helpful in its prevention.