Anal cancer grows at different rates for different people. It develops quickly in some individuals and slowly in others. Treatment is most likely to be effective when a doctor detects anal cancer early.

In many cases, a doctor can detect anal cancer in its early stages. In some cases, a delay in diagnosis can allow the cancer to advance before it is found.

Anal cancer is when the cells of the anus grow and divide abnormally quickly, forming anal tumors. As this cancer grows, the tumors will get larger and possibly more numerous. Anal cancer may also spread to other body parts.

A 2022 article notes that anal cancer is rare, consisting of 2.5% of all cancers affecting the digestive system. In the United States, the probability of a person developing anal cancer during their lifetime is 0.2%. However, anal cancer is a potentially life threatening condition, especially in its later stages.

This article examines how fast anal cancer grows. It also looks at how it progresses and a person’s outlook.

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Anal cancer is not universally fast growing or slow growing.

According to the same 2022 article, anal cancer can grow slowly in some people but quickly in others. Scientists do not understand why this difference exists.

Metastasis is when a cancer that began in one organ spreads to a different area of the body.

There are many ways that anal cancer could spread to other body parts. However, as a study in Gastrointestinal Tumors explains, anal cancer cells typically enter the lymphatic system. They will then travel to either of the following lymph nodes:

  • the internal iliac lymph nodes
  • the superficial inguinal lymph nodes

From these lymph nodes, the cancer cells can spread to distant organs. This might be via the lymphatic system again or through the blood.

Where does it usually spread to first?

If anal cancer does metastasize, it most commonly spreads to the liver, followed by the lungs.

In theory, anal cancer could metastasize to any organ. Anal cancers have spread to the brain, the irises, and various lymph nodes. However, it is unusual for anal cancer to metastasize in these ways.

The outlook for those with anal cancer depends on how much it has developed.

According to the American Cancer Society (ACS), the 5-year relative survival rate for anal cancer is as follows:

  • Localized: These anal cancers have not spread outside of the anus. The 5-year relative survival rate is 83%.
  • Regional: These anal cancers have spread to nearby organs or lymph nodes. The 5-year relative survival rate is 67%.
  • Distant: These anal cancers have spread to distant organs. The 5-year relative survival rate is 36%.

The overall 5-year survival rate for anal cancer is 70%.

Outlook without treatment

Doctors have developed several methods for treating anal cancer. According to the National Cancer Institute (NCI), common treatment methods include:

  • surgery
  • radiation therapy
  • chemotherapy

It is difficult to estimate how treatment affects the outlook for people with anal cancer.

Curing anal cancer should reduce symptoms and improve survival rates. An article in the British Medical Journal states that the cure rate for anal cancer is 75–95%.

However, although this figure is high, the matter is complicated. Some people with anal cancer can develop this condition again, even after treatment.

Anal cancer is neither fast nor slow growing. It develops quickly in some people and slowly in others. The reasons for this are unclear.

Anal cancer can spread to other organs. This process usually begins when cancer cells enter the lymphatic system. They will then enter the lymph nodes before spreading further throughout the body via the bloodstream or lymphatic system.

In the early stages of anal cancer, the 5-year survival rate is high. The survival rate drops as the cancer develops. However, some anal cancer treatments are very effective.