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Anal cancer is a type of cancer that develops in the tissues of the anus, the opening at the end of the digestive system. It is uncommon, but understanding its symptoms and risk factors can help people recognize unusual changes and seek medical care when needed.

Some risk factors can be reduced, while others cannot be changed. Learning about prevention and regular medical care can also help lower certain risks.

What Is Anal Cancer?

The anus is the final part of the digestive tract. It allows stool to leave the body.

Anal cancer develops when abnormal cells in this area begin to grow uncontrollably. Different types of cells are found around the anus, so anal cancer can have different forms. Squamous cell carcinoma is the most common type.

Anal cancer is different from colorectal cancer, which begins in the colon or rectum.

What Are the Symptoms of Anal Cancer?

Anal cancer may cause symptoms that can look like hemorrhoids, infections, or other common problems. This is one reason persistent symptoms should not be ignored.

Common symptoms can include:

Bleeding From the Anus

Blood on toilet paper, in the toilet, or mixed with stool can occur. Although hemorrhoids are a common cause of rectal bleeding, unexplained or repeated bleeding should be checked by a healthcare professional.

Pain or Pressure

Some people may experience pain, pressure, or discomfort around the anus. The discomfort may become more noticeable during bowel movements.

A Lump or Growth

A lump, swelling, or unusual growth around or inside the anus may be a warning sign.

Changes in Bowel Habits

Some people may notice changes such as:

• Diarrhea or constipation

• Narrower stools

• A feeling that the bowel has not emptied completely

• Increased urgency to have a bowel movement

• Itching or Discharge

Persistent anal itching or unusual discharge can also occur.

These symptoms do not necessarily mean cancer. Conditions such as hemorrhoids, anal fissures, and infections can cause similar problems.

What Are the Major Risk Factors?

Several factors can increase the chance of developing anal cancer.

Human Papillomavirus

Human papillomavirus (HPV) infection is the most important known risk factor for anal cancer. Certain high-risk types of HPV can cause changes in cells that may eventually become cancerous.

HPV is very common, and having HPV does not mean that someone will develop cancer.

Weakened Immune System

People with weakened immune systems may have a higher risk. This can include people taking certain medicines that suppress immunity or those living with conditions that affect immune function.

Previous HPV-Related Conditions

A history of certain HPV-related cancers or abnormal cell changes may be associated with increased risk.

Smoking

Smoking is associated with a higher risk of anal cancer. Tobacco contains chemicals that can damage cells and interfere with the body's ability to deal with abnormal cell changes.

Increasing Age

The risk of anal cancer generally increases with age, although it can occur in younger adults as well.

Previous Anal or Cervical Conditions

A history of certain cancers or precancerous conditions involving the cervix, vagina, vulva, or anus may increase risk because these conditions can be linked to HPV infection.

Can Anal Cancer Be Prevented?

Not every case can be prevented, but some steps may lower the risk.

HPV Vaccination

HPV vaccination can protect against HPV types that are responsible for many HPV-related cancers. Vaccination is most effective when given before exposure to the virus, but eligibility can vary by age and individual circumstances.

Avoid Tobacco

Not smoking can reduce the risk of several cancers, including cancers associated with tobacco exposure.

Practice Safer Sex

Using condoms and other barrier methods can reduce the chance of HPV transmission, although they do not provide complete protection because HPV can infect areas not covered by them.

Regular Medical Care

People with increased risk may benefit from discussing screening or other preventive care with a healthcare professional.

How Is Anal Cancer Diagnosed?

If symptoms are present, a doctor may perform a physical examination and inspect the area around the anus.

A digital rectal examination may also be used to check for unusual lumps or changes.

An anoscopy may allow a healthcare professional to examine the anal canal more closely. If an abnormal area is found, a biopsy may be performed.

During a biopsy, a small tissue sample is removed and examined under a microscope to determine whether cancer cells are present.

Additional imaging tests may be used if cancer is diagnosed to understand its size and whether it has spread.

When Should You See a Doctor?

Persistent anal bleeding, pain, a lump, unusual discharge, or changes in bowel habits should be discussed with a healthcare professional.

Because these symptoms can have many causes, they do not automatically mean cancer. However, getting persistent symptoms checked can help identify the correct cause and allow treatment to begin when necessary.

FAQs

What is the most common risk factor for anal cancer?

Persistent infection with certain high-risk types of HPV is the most important known risk factor.

Is anal cancer the same as colorectal cancer?

No. Anal cancer begins in the anus, while colorectal cancer develops in the colon or rectum.

Can HPV cause anal cancer?

Certain high-risk HPV types can cause changes in anal cells that may eventually lead to cancer.

Can anal cancer be prevented?

Some risk can be reduced through HPV vaccination, avoiding tobacco, practicing safer sex, and receiving appropriate medical care.

Is anal bleeding always a sign of cancer?

No. Hemorrhoids, anal fissures, infections, and other conditions can cause bleeding. Persistent or unexplained bleeding should still be evaluated.

Conclusion

Anal cancer is uncommon but can cause symptoms such as anal bleeding, pain, a lump, itching, discharge, or changes in bowel habits. HPV infection is the most important known risk factor, while smoking, a weakened immune system, age, and certain previous conditions can also increase risk.