Anal canal is a short tube-like structure, about 2-3 cm in length, at the end of the digestive tract or large intestine. It throws the solid waste out of the body, thus playing a vital role in the human digestive system. Anal cancer is a rare condition in which due to certain genetic mutation normal cells of the anal canal begin to grow abnormally at an uncontrolled rate.
Anal cancer is more commonly found in men in the age group of 50-60 years. Almost 50% of the anal cancer cases are diagnosed in early stages while 15-30% when the cancer has spread and about 10-20% in advanced stages.
There are four stages of anal cancer as shown below:
- Stage 0 is known as carcinoma in situ. In this stage, only the cells found in the innermost lining of the anus begins to divide uncontrollably.
- Stage 1 occurs when the tumour has become about 2cm in size.
- Stage 2 is characterised by further growth of tumour to a size greater than 2cm.
- Stage 3 involves spreading of cancer to the lymph nodes near the rectum and other nearby organs such as vagina, bladder and urethra.
- Stage 4 is when the tumour spreads beyond lymph nodes and nearby organs to more distant parts of the body.
What are the causes and risk factors?
Exact reason cannot be ascertained but following are considered to increase the risk for anal cancer:
- Those people who are between 35-60 years of age
- Single men compared to married men
- Anal sex
- Anal infection with Human Papillomavirus (HPV)
- Genital warts
- Drugs or conditions that suppress immunity system such as HIV
- Having multiple sexual partners
- Anal fistulas
- Excessive use of tobacco
What are the signs and symptoms?
- Anal or rectal bleeding
- Anal itching
- Pain or pressure in the anus
- Unusual discharge from the anus
- Lump or abnormal growth near anus
- Change in bowel habits
If any of such symptoms bother you, then you need to talk to your medical practitioner immediately.
How is anal cancer diagnosed?
There methods are used for diagnosing anal cancer:
- Routine Digital Rectal Exam (DRE)
- Invasive procedures such as anoscopy, proctoscopy or endorectal ultrasound
What is the treatment?
Treatment varies depending on the stage, overall health and preference of the patient. It involves the use of chemotherapy, radiation therapy or surgery. Sometimes a combination of chemotherapy and radiation therapy is used to increase the impact but it aggravates the side effects also.
- Chemotherapy involves the use of cancer-fighting drugs which are administered through either injection or as pills
- Radiation therapy involves the use of high powered beams like x-rays
- Generally doctors recommend surgery for either early-stage anal cancer or late-stage if not responded to chemotherapy/radiation therapy. In surgery, tumour is removed along with little bit surrounding healthy tissue.
- In case of advanced stages of anal cancer, a more extensive operative procedure called abdominoperineal resection (AP resection) is done. In AP resection surgery, surgeon removes the anal canal, rectum and a portion of the colon. The remaining part of the canal if then joined with an abdominal opening through which waste will leave from the body and collects in a colostomy bag.
How to prevent anal cancer?
There is no such sure shot way to prevent anal cancer but following are advised:
- Practice safe sex and limit the number of your sex partners
- Abstain from anal intercourse
- Get vaccinated against HPV infection
- Stop smoking and use of other types of tobacco