Skip to nav Skip to content

The experts at Moffitt Cancer Center are often asked what causes anal cancer. Unfortunately, as of yet there are no clear-cut answers. Scientists have confirmed that cancer forms when healthy cells undergo changes that cause them to multiply uncontrollably or remain viable long after they should die. The excess cells can bind together and form masses, or tumors, which can potentially invade nearby lymph nodes and spread to distant organs. The underlying causes of these cellular mutations, however, remain uncertain.

What are some common causes of anal cancer?

One theory suggests that anal cancer may be connected in some way to the human papillomavirus (HPV), a sexually transmitted infection. This is based on the fact that evidence of HPV is found in nearly all patients with anal cancer, especially those with squamous cell carcinomas. Nevertheless, the majority of patients with HPV do not develop anal cancer. Research is underway to clarify the role of HPV, if any, in the development of anal cancer.

In addition to what is known about HPV, other possible causes of anal cancer include:

  • A weakened immune system – If the body’s ability to fight off infections is impaired by the use of certain medications or the human immunodeficiency virus (HIV), viruses like HPV tend to become more active, which can possibly trigger anal cancer.
  • Smoking – The cancer-causing chemicals contained in tobacco smoke can travel from the lungs to other areas of the body, including the anus. Smoking can also impair the body’s immune system, making it less effective at fighting off HPV and other infections.
  • Other types of cancer – While a causal link has not been conclusively established, anal cancer sometimes develops in women with cervical, vaginal or vulvar cancer, and men with penile cancer.

It’s important to note that, in many cases, anal cancer appears to be unrelated to any of these factors, and its specific causes are unknown. The respected researchers at Moffitt Cancer Center, a National Cancer Institute-designated Comprehensive Cancer Center, continue to learn more about how to prevent, detect and treat anal cancer, and how to enhance the lives of patients who have the condition.

If you’d like to discuss current theories on what causes anal cancer, including HPV, call 1-888-663-3488 or complete a new patient registration form online. No referrals are required.