Overview of Anal Cancer

Anal cancer is a type of cancer that starts in the anus, the short canal at the very end of the digestive tract. The anus is only about 1.5 inches long and serves as the body’s exit for waste after food has been digested. This area is made up of different types of cells, including squamous cells—thin, flat cells that form a skin-like lining—and gland cells, which produce mucus to keep the area moist. In anal cancer, cells in this area begin to grow abnormally, forming a tumor that can spread if not treated.

Although anal cancer is rare, its incidence has been increasing, and certain groups have a higher risk. These groups include individuals with HPV infections, people with weakened immune systems, and those who engage in receptive anal sex. Most cases of anal cancer are linked to human papillomavirus (HPV), a common virus that can cause changes in cells over time. Increasing awareness about HPV and vaccination is especially important for preventing anal cancer, particularly in communities that may face barriers to healthcare.

Anatomy of the Anus

To understand anal cancer, let’s look briefly at the anatomy of the anus and its role in the digestive system:

• Digestive Process: After food is broken down in the stomach and intestines, waste travels through the large intestine and into the rectum, where it waits until the body is ready to pass it.

• The Anus: The anus connects the rectum to the outside and allows waste to leave the body. It contains muscles and nerves that help control bowel movements, keeping the body’s waste system functioning properly. The anus is lined with different types of cells that, under normal conditions, grow, die, and are replaced at a healthy rate.

• Cell Types: Different cells in the anus serve different functions. Squamous cells form the lining, similar to skin cells, while gland cells produce mucus to lubricate the area. When cancer develops, it usually starts in these squamous cells.

Where Does Anal Cancer Fit Among Other Cancer Types?

Anal cancer is less common than many other cancers among the general population, however among gay and bisexual men, the risk is greater. Each year, about 9,000 people in the United States are diagnosed with anal cancer, accounting for a small fraction of all cancer cases. However, awareness of anal cancer is essential, especially in high-risk communities and in those with less access to healthcare, as early detection can improve treatment outcomes.

Anal cancer is often grouped with other gastrointestinal (GI) cancers but is distinct from other types, such as colon or rectal cancer. Colon and rectal cancers develop further up in the digestive system, where the body absorbs nutrients and water from food. Anal cancer, however, affects the very end of the digestive tract. Because of this, anal cancer is treated as its own category, with specific prevention and treatment methods.

Even though it’s not as common, anal cancer is becoming more widely recognized, especially as we understand more about its link to HPV. Awareness of HPV vaccination and safe sexual practices can help reduce the risk, particularly in communities where healthcare access, vaccine availability, and health information may be limited. If you’re unsure of available resources, many organizations work to provide low-cost or free HPV vaccines and screenings to help reduce barriers to care. Learning about this cancer type and understanding how it affects the body can help people take preventive steps, access resources, and seek early treatment if symptoms appear.