Overview
Anal Cancer Anal Cancer is a malignancy or cancerous growth in or near the anal region of the human excretory system.
Associated Anatomy of Anal Cancer
Anus is the opening of the rectum or the canal at the end of the alimentary tract for the passage of feces.
Stages of Anal Cancer
- Stage 0: Also called as carcinoma in situ, here the abnormal cancerous cells are present in the lining of the anus only.
- Stage I: The tumor is around 2 cm and is localised with minimal or no spread to lymph nodes or other parts of the body.
- Stage II: The tumor is more than 2 cm in size with minimal or no spread to lymph nodes or other parts of the body.
- Stage IIIA: The tumor eventually spreads to either the nearby lymph nodes or to organs, such as the urethra, bladder, or a woman’s vagina.
- Stage IIIB: The tumor has invaded other nearby organs, but lymph node spread is limited to the area around the rectum; there is no distant spread.
- Stage IV: The tumor has definitely spread to the distant lymph nodes and to other parts of the body.
- Recurrent: Recurrent cancer is cancer that has come back after treatment.
Anal Cancer Causes
- Receptive anal intercourse: Anal intercourse predisposes the receiving partner to anal cancer.
- Human Papillomavirus (HPV) infection: HPV infection affects the reproductive system mainly through sexual contact which predisposes an individual to anal cancer.
- Immunocompromised patients: Individuals who have a deficient immune system especially those with HIV or AIDS have a higher chance of developing anal cancer.
Anal Cancer Symptoms
- Pain in the anal region that may disturb daily activities.
- Abnormal anal discharge and leakage.
- Painful bowel movements.
- Change in bowel movement patterns such as constipation, hard stools, and/or watery stools.
- Anal bleeding and/or ulceration.
- Skin itching near the anus.
- Presence of a lump or swelling in the anal region.
- Signs- tenderness and lumps felt on rectal digital examination.
Anal Cancer Diagnosis & Tests
- Detailed patient history is taken consisting of medical history, sexual history, and any other drugs being taken.
- Digital rectal examination is performed by an oncologist (doctor who specialises in cancer) or certified medical professional to palpate the anus, rectum, and surrounding tissues to confirm the presence of any lumps, ulceration, and/or swelling and tenderness.
- Other tests include proctoscopy or anoscopy (screening the rectum and anus through a tiny camera), biopsy to assess the mass for cancerous cells, and an MRI to rule out other possible reasons for a mass. PET CT is needed to stage the disease.
Differential Diagnosis of Anal Cancer
- Anal fissures and hemorrhoids are the most common diagnosis in the initial stages of symptoms. Symptoms are very common and therefore need a high degree of suspicion for anal cancer diagnosis.
- Other conditions to be ruled out are anal fistulas (openings or abnormal pathways), chancroids, Paget disease, psoariasis (skin disease), and genital warts.
Anal Cancer Treatment
- Radiation: Radiation therapy with high-energy x-rays is utilised before a surgical approach as the first line of treatment to clear the cancerous tissues.
- Chemotherapy: Chemotherapy drugs are also helpful in mild or early stages of Anal Cancer before surgery is performed.
- Surgery: Surgery, in most cases is reserved for patients with anal cancer unresponsive to radiation or chemotherapy. Surgery involves removing the tumor as a whole without damaging healthy tissues called a local excision. Robotic surgery offers the option of scarless surgery with rapid & enhanced surgery.
- Another approach is the abdominoperineal resection, where the anus, rectum, and some parts of the bowel are removed along with lymph nodes.
- Counselling: Patients and caregivers must be counselled for further management and home care. They should be educated about good hygiene and maintain regular follow up with treating doctors.
Risk Factors of Anal Cancer
- Age: Anal cancer occurs in individuals above the age of 50. It is a non-modifiable risk factor.
- Human Papillomavirus (HPV) disease: The presence of either oral or urogenital HPV disease may increase the risk of anal cancer.
- Smoking is an important modifiable risk factor - One can quit smoking to reduce this risk. Consumption of tobacco has also been known to cause Anal Cancer.
- Research has suggested that Anal intercourse can cause Anal Cancer and multiple sexual partners with or without protection may cause individuals to develop sexually transmitted diseases and subsequent Anal Cancer.
Anal Cancer Prevention
Primary Prevention of Anal Cancer
- If practiced, anal intercourses should be performed with proper precautions.
- Self-examination: One must observe for signs and symptoms of anal cancer such as an abnormal lump, discharge, pain, change in bowel movement patterns.
- Quit smoking or do not start smoking
- Get an HPV vaccine to minimize the risk of HPV infection.
Secondary Prevention of Anal Cancer
- Completion of radiation and chemotherapy protocol to prevent recurrence of the tumor.
- Regular follow-up with a treating doctor.
- Practice safe sex.
Possible Complications of Anal Cancer
- After an abdominoperineal resection surgery, a colostomy bag is attached to the abdomen to facilitate the excretion of stools from the intestines. Infection can develop because of unhygienic conditions.
- Damage or loss of bowel and bladder function can occur due to metastasis or surgical complications.
- Treatment with radiation and chemotherapy has side effects but is manageable with proper measures.
Anal Cancer Epidemiology
- Age: Commonly seen in people above the age of 50.
- Race and religion: Race and religion do not affect the occurrence of anal cancer.
- Gender: Men are more prone to get anal cancer than females.
- Immunocompromised state: Individuals who are on drugs for conditions that cause immune system deficiency are at a higher risk for anal cancer. Examples include HIV and AIDS.
Expected Prognosis of Anal Cancer
Anal cancers are treatable with a life expectancy of more than 90%. Most tumours respond well to chemotherapy and radiation therapy. Quality of life is high in most cases.
Natural Progression of Anal Cancer
If left untreated, anal cancer can metastasize to other organs and lymph nodes and lead to death.
Pathophysiology of Anal Cancer
The development of abnormal anal fistulas and lumps may disturb normal bowel movement patterns and can also cause diarrhea.