Anal Cancer: Causes, Symptoms, Diagnosis, and Treatment

Anal cancer is one of the least common cancers of the large intestine. It involves the anal region. It is most commonly seen in Caucasian females and least commonly seen in Asian males. It accounts for 2.5 % of all digestive system cancer. It is most commonly seen in the individual with high-risk sexual activity, with a history of any associated malignancy, or in an individual with a previous history of any Human Papilloma Virus infection. Peak incidence is seen at 70 years of age but is highly variable.

Classification of anal cancer is provided as follows −

  • Squamous cell carcinoma

  • Adenocarcinoma

  • Small cell carcinoma

  • Undifferentiated carcinoma

Anal Cancer: Causes

The probable causes of anal cancer may include −

  • Human Papilloma Virus infection

  • HIV-positive individual with low CD 4 cell count

  • High-risk sexual behavior; most common in homosexual males with almost 15 times more risk.

  • Immune deficiency condition such as after transplant or steroid ingestion.

  • Anal warts can lead to anal cancer

  • History of cervical or vaginal cancer or cancer of the vulva.

  • Multiple sexual partners.

  • Smoking can cause anal cancer

  • Abnormal proliferation of the anal cells due to innate and genetic factors.

Most anal cancers arise from the pre-cancerous changes of the anal canal and the skin layer present around the anal canal. It is most commonly derived as Squamous cell cancer and it can obviously spread to other parts of the body.

Anal Cancer: Symptoms

The following are the major symptoms of anal cancer −

  • Stool stained with blood or rectal bleeding

  • Anus or rectal pain or discomfort while defecating

  • A tumor or mass in the rectum or anus

  • An itchy or discharging anus

  • A modification in bowel patterns, such as diarrhea or constipation

  • A sensation of satiety in the anus or rectum

  • A modification in the stool's form or characteristics

Anal Cancer: Risk Factors

The major risk factors of anal cancer include −

  • Human papillomavirus (HPV) infection − This is the biggest risk factor for anal cancer since some HPV strains are known to alter the anus cells in ways that can cause cancer.

  • Anal intercourse − Males who have sexual intercourse with other men, in particular, are more likely to develop anal cancer.

  • Smoking − Smoking increases your risk of getting anal cancer. The cells in the anus can be harmed by the chemicals in cigarette smoke, raising the risk of cancer.

  • Anal precancerous lesions (anal dysplasia) − Anal cancer risk is increased by a history of precancerous anal lesions (anal dysplasia). HPV infection may be the cause of these aberrant cells.

  • Anal cancer in the family − People who have a family history of the disease may be at a higher risk of getting it themselves.

  • Chronic inflammatory diseases − Some inflammatory diseases, like Crohn's disease and ulcerative colitis, can raise the chance of developing anal cancer.

  • Age − As people age, their risk of developing anal cancer rises; people over 50 accounts for the majority of cases.

  • HIV infection − Anal cancer is more likely to strike those who have the virus.

  • Immune system weakness − Individuals with immune system weakness, such as those with HIV or taking immunosuppressive medication, may be more susceptible to developing anal cancer.

Anal Cancer: Diagnosis

To diagnose anal cancer, some of the prominent methods are −

  • Biopsy to confirm the diagnosis of anal cancer

  • Detailed medical history

  • Detailed clinical full-body examination

  • Rectal examination with fingers

  • Complete blood counts with kidney function test

  • Proctoscopy − Visualization of the anal canal with a special instrument directly by the naked eye

  • MRI scan of the pelvis region

  • CT scan of the abdominal and thoracic region

  • In females’ genital examination to rule out other malignancy

  • Test for HIV

  • Biopsy of the lymph nodes

  • PET scan

  • Colonoscopy

  • Ultrasound of the anal region

Anal Cancer: Treatment

Major methods of treatment include the following −

  • Abdominoperineal resection − Previously this surgery was advisable for most of the patients but with the latest advancement in other modalities of treatment this procedure is no longer the treatment of choice.

  • Radiation therapy − This therapy can lead to a 5-year survival rate in 70% of the patient, but there are very high side effects of this procedure that lead to fibrosis or stiffening of the anal region.

  • Chemotherapy − Chemotherapy with 5 Fluoro Uracil and cisplatin along with low-dose radiation therapy has a better 5-year survival rate with very few patients requiring any need of secondary procedures. With low-dose radiation, the toxic effect of the radiation can be avoided.

  • Radiation therapy along with Mitomycin C has shown a better outcome in a few studies.

Anal Cancer: Prevention

Following are the steps that can be taken to reduce the risk of anal cancer −

  • To reduce the incidence and treat the HPV infection at the earliest.

  • HIV patients should be screened if they have any such symptoms.

  • Sexual orientation and activity should be taken proper care of.

  • Cessation of cigarette smoking.

  • Any symptoms with the alteration in bowel habits should be discussed with the experts.


Anal cancer is a disease of the elderly but can occur in any age group with female gender preponderance. The high-risk individual should be given proper medical advice and proper screening should be done. Symptoms such as bleeding from the anal region, excessive itching, mass near the anus, discharge from the anus, and change in bowel habits should be screened thoroughly.

With the advent of modern diagnostic tools, the disease can be identified at an early stage, and with advanced treatment modalities such as radiation therapy, chemotherapy, and surgical techniques the survival rates of the patients can be increased and it could reduce the mortality and morbidity also. Patients with anal cancer need proper emotional, medical, and physical help to carry out their activity; therefore, self-help groups along with NGOs should come forward to provide such care and support.

Dr. Durgesh Kumar Sinha
Dr. Durgesh Kumar Sinha


Updated on: 16-Feb-2023


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