What are anorectal cancers?
Rectum is that part of the digestive system where food waste reaches after nutrients and water are absorbed in the small and large intestine respectively. Anus forms the outlet to the gastrointestinal tract or anal canal at the end of rectum. Food waste is temporarily stored in the rectum before being passed through the anal canal, out of the anus as stool.
Anal cancers are rare forms of cancer that occurs in the anal canal. Rectum cancer generally begins as cellular changes in the topmost layer of the epithelium.
What are the causes of the disorder?
Cancer develops when normal cells multiply at an uncontrolled rate and accumulate to form a mass of cells (tumour). Though the exact cause of anorectal cancer is not known but the following conditions increase a person’s risk towards developing the same:
For anal cancer:
- Age (especially over the age of 50)
- Multiple sexual partners and anal sex
- Human papillomavirus (HPV) infection
- Drugs or immunosuppressant drugs
For rectal cancer:
- History of colon cancer in family
- Inflammatory bowel disease like ulcerative colitis
- Polyps in rectum
- High fat, low fibre diet
What one needs to know about symptoms or signs?
A person suffering from anorectal cancer may experience the following symptoms:
- Bleeding from anus or rectum
- Pain in the region of anus or abdomen (for rectal cancer)
- Anal itching
- A mass or growth in the anal canal
- Changes in bowel habits (constipation or diarrhoea); urgency in bowel motions
- Sensation of full bowel even after emptying
Which specialist should be consulted in case of signs and symptoms?
A general practitioner must be consulted if a person experiences abdominal and bowel discomfort. The doctor will refer the patient to a gastroenterologist, who is a specialist doctor for treatment of diseases of the digestive system. Further diagnosis and tests may also require the expertise of an oncologist (specialist in treating cancer).
What are the screening tests and investigations done to confirm or rule out the disorder?
The cancer is diagnosed on the basis of the following tests and procedures:
- Physical examination – Through a digital rectal exam, the doctor inserts a gloved, lubricated finger into the patient’s rectum to feel for any lumps or growths.
- Visual inspection of anus and rectum – Using a short, lighted tube called the anoscope, proctoscope or sigmoidoscope, the doctor inspects the rectum and anal canal for abnormal changes.
- Ultrasound – A probe is inserted into the rectum, which emits ultrasound waves that generate an image of the anal canal and rectum.
- Biopsy – A small sample of the affected tissue is taken from the person’s body and examined in the laboratory for cancerous cells.
Staging the cancer: Once anorectal cancer diagnosis is confirmed, the doctor will conduct imaging tests like computerised tomography (CT) scan, magnetic resonance imaging (MRI) and positron emission tomography (PET) to determine the extent and spread of the cancer.
What treatment modalities are available for management of the disorder?
The mode of treatment recommended for a patient depends on the stage of the cancer and the physical condition of the patient. Treatment consists of the following:
- Early stage anal cancer surgery removes small cancers in the anus and along with some surrounding healthy tissue. Surgeons need to take care of removing the tumour without damaging the anal sphincter muscles that control bowel movement.
- Early stage rectal cancer surgery involves removal of cancerous rectal tissue along with surrounding healthy rectal tissue and lymph nodes either through the anus or small incisions in the abdomen.
- Advanced anorectal cancer surgery or abdominoperineal resection (AP resection) in which the surgeon removes the anal canal, rectum and part of the colon. The remaining part of the colon is then attached to an opening in the abdomen through which waste exits the body and collects in a colostomy bag. This procedure diverts the bowel from the anus and into the opening (stoma) and is used for anal and rectal cancers that require a large amount of tissue removal making it impossible to sew the tract back together.
What are the known complications in management of the disorder?
Chemotherapy drugs cause strong side effects like hair loss, nausea and vomiting. The treatment also kills healthy cells in the gastrointestinal tract and hair follicles. Radiation treatment can cause redness in the skin and sores in and around the anus, along with changes in the anal canal.
What precautions or steps are necessary to stay healthy and happy during the treatment?
Regular follow-up examinations and tests will monitor the success of the treatment and detect any abnormal changes.
How can the disorder be prevented from happening or recurring?
There is no known method to prevent anorectal cancer but people can reduce their risk factor towards developing it by following healthy lifestyle habits like quitting smoking and practising safe sex in order to avoid HPV infections.