Anal Cancer - Types, Signs, Symptoms, Causes, and Treatment

What Is Anal Cancer?

Anal cancer, otherwise called carcinoma of the anal canal, is a rare type of cancer found in the anal canal, the tube present at the end of the digestive tract through which feces leaves the body. When the cells that line the anal canal become abnormal, they can form benign (noncancerous) or malignant (cancerous) tumors in the anus, resulting in anal cancer. This rare tumor can spread to other parts of the body, and a few noncancerous anal tumors can turn cancerous over time. Almost 50 % of all cases of anal cancers are diagnosed before cancer cells spread beyond the initial site. In 13 to 25%, it is diagnosed after cancer cells spread to the lymph nodes, and in 10%, after cancer cells have traveled to distant organs. Anal pain and rectal bleeding are common symptoms associated with this type of cancer.

When diagnosed early, anal cancer is highly treatable. The anus is lined by tissue from the skin and intestine. The most common type of anal carcinoma is SSC or squamous cell carcinoma, a type of skin cancer. The treatment is usually done with a combination of chemotherapy and radiation therapy. Combining two or three treatment options increases the chance of a cure, but it also increases the incidence of side effects. The five-year survival rate of people diagnosed with anal cancer is 67%.

What Are the Types of Anal Cancer?

The following are some common types of anal cancer:

1. Benign Anal Growths - Bening or noncancerous growths in the anus like skin tags, polyps, genital warts, and granular cell tumors.

2. Precancerous Lesions in the Anus - Benign growths that are capable of turning malignant over time. Examples include anal squamous intraepithelial neoplasia (ASIL) and anal intraepithelial neoplasia (AIN).

3. Squamous Cell Carcinoma - As mentioned before, it is the most common type of anal cancer. These are cancerous or malignant tumors in the anus that originate from abnormal squamous cells.

4. Squamous Cell Carcinoma In Situ - Otherwise called Bowen’s disease. Here, abnormal squamous cells are seen on the surface of the anal canal and not in the deeper layers.

5. Adenocarcinoma - Another rare type of anal cancer that originated from the glands present around the anus.

6. Basal Cell Carcinoma - It is also a type of skin cancer that forms in the skin exposed to the sun. It is a rare form of anal cancer.

What Are the Signs and Symptoms of Anal Cancer?

The possible signs and symptoms of anal cancer are:

• Rectal bleeding - blood in stools.

• Itching around the anus (pruritus).

• Anal pain.

• Lumps or bumps around the anus.

• Mucus discharge from the anus.

• Bowel incontinence or loss of bowel control (leaking stool).

• Constant urge to pass stools.

A few people with anal cancer do not experience any symptoms. These symptoms are not specific, and the chances of anal cancer are significantly less, even if you have these symptoms. Piles or hemorrhoids and anal fissures can result in similar signs and symptoms.

What Are the Causes of Anal Cancer?

Scientists believe that infection with the human papillomavirus (HPV) is linked to anal cancer. But, this does not mean that getting infected with HPV will definitely lead to anal cancer. HPV infection, along with other risk factors, are believed to trigger the growth of anal cancer. Certain risk factors turn healthy cells in the anal canal abnormal. These abnormal cells, unlike the healthy cells, do not grow and multiply at a set rate and die eventually, but multiply out of control and keep accumulating. The abnormal cells can also go deeper and invade nearby tissues and distant organs.

Who Is at Risk of Developing Anal Cancer?

Women are more at risk of developing anal cancer than men. About 1 in 500 to 600 people are affected by this cancer. There are various factors that increase the risk of a person developing anal cancer. The following individuals are more prone to anal cancer:

1. People who are 50 years or older.

2. Those who have multiple sexual partners in their lifetime.

3. Those who receive anal sex.

4. Smokers.

5. Those with a history of cervical, vulvar, or vaginal cancer.

6. HPV infection increases not only the risk of anal cancer, but also cervical cancer. This virus is transmitted sexually and can result in genital warts.

7. Having an anal fistula, an abnormal opening present between the anus and the surrounding skin.

8. Organ transplant patients, as they take immunosuppressive drugs to prevent organ rejection.

9. HIV (human immunodeficiency virus) infection, as it suppresses the immune system.

How Is Anal Cancer Diagnosed?

The doctor might conduct the following tests and procedures to diagnose anal cancer:

• Medical History - You will be asked about habits and previous history of illnesses and treatments.

• Digital rectal examination (DRE) - It is a type of physical examination of the rectum and anus. Here, the doctor inserts a lubricated (and gloved) finger into the anal canal to feel for abnormal growths and bumps.

• Anoscopy - A short and lighted tube called an anoscope is used to examine the anus.

• Proctoscopy - A thin tube with a light called a proctoscope is used to look inside the anus and rectum. It is used to look for abnormal lesions or growths and to collect tissue samples for testing.

• Biopsy - The collected tissue sample or biopsy during proctoscopy or anoscopy is viewed under a microscope to look for signs of cancer.

• Endo-anal Ultrasound - A ultrasound probe is inserted into the anus to get images of the anal canal.

Once these tests show you have an abnormal growth or tumor in the anus, the doctor will suggest getting computerized tomography (CT), magnetic resonance imaging (MRI), or positron emission tomography (PET) to assess if the cancer cells have spread to the surrounding lymph nodes or distant organs.

What Are the Treatment Options for Anal Cancer?

Based on your age and how advanced the cancer is, the treatment options include:

1) Chemotherapy - These drugs are used to kill and prevent cancer cells from growing. It can be taken orally or directly injected into the veins.

2) Radiation Therapy - High-energy X-rays are also commonly used to kill cells of anal cancer. It is a non-invasive treatment option and is used along with chemotherapy or surgery.

3) Surgery - Tumor in the anus that has not spread to nearby structures is usually treated surgically through local resection surgery. Here, the tumor, along with some healthy tissue surrounding it, is removed. This surgery is done if the tumor is diagnosed during the early stages. Abdominoperineal (AP) resection, a more invasive surgery, is done in late-stage anal cancers where other treatment options did not help much. Here, the anus, rectum, and parts of the colon are removed.

Prevention:

The following tips might reduce your risk of anal cancer:

1. Avoid or quit smoking.

2. Use condoms and practice safe sex.

3. Get vaccinated against the human papillomavirus (HPV).

Most people diagnosed with anal cancer live long and healthy lives. Early diagnosis is vital for this. The five-year survival rate for patients with anal cancer is 67 %, and localized anal cancers have a survival rate of 81.3 %. For more information, consult a surgical gastrologist or oncologist online.