Anal Cancer

How is anal cancer diagnosed?

A healthcare provider will ask you about your symptoms, including how long you’ve had them. They’ll ask about your medical history, including conditions that affect your immune system. They may also ask about your sexual activity.

What tests will be done to diagnose this condition?

Your provider will do a digital rectal examination. They’ll do an anal Pap test or biopsy to obtain cells for a medical pathologist to examine under a microscope. (Women and people AFAB may have pelvic examinations.) Your provider will also do endoscopic tests and imaging tests.

Endoscopic tests

Providers do endoscopic tests to look inside your rectum and anus. They do these tests using special instruments that are thin, flexible tubes that have a light, a lens and a video camera. They may take tissue samples (biopsy) for pathologists to examine. Endoscopic tests include:

• Anoscopy, which involves providers using a short lighted tube called an anoscope to look at your anus and lower rectum.
• Flexible sigmoidoscopy to check for tumors and polyps in your rectum and anus.
• Colonoscopy to look at your entire colon for signs of tumors and polyps.

Imaging tests

Imaging tests help providers learn more about tumors, including tumor size and specific location. Imaging tests may include:

• Magnetic resonance imaging (MRI) scan.
• Transrectal ultrasound.
• Computed tomography (CT) scan.
• Positron emission (PET) scan.

Anal cancer staging

Healthcare providers use cancer staging systems to plan treatment and set prognoses, or what you can expect to happen after treatment. They consider factors like tumor size, if there’s cancer in your lymph nodes and whether the tumor has spread or metastasized. There are five stages of anal cancer:

Stage 0

There are abnormal cells in your anus’ mucosa, which is the innermost lining of your anus. The abnormal cells aren’t cancerous but may become cancerous. Stage 0 anal cancer is also called high-grade squamous intraepithelial lesion (HSIL).

Stage I

Cancer cells have formed a tumor that measures 2 centimeters or less, or about the size of a peanut.

Stage II

Stage II anal cancer is divided into two stages:

• Stage IIA means there’s a tumor that’s larger than 2 centimeters but smaller than 5 centimeters.
• Stage IIB means that a tumor is 5 centimeters — about the size of a lime — but hasn’t spread from your anus.

Stage III

Stage III is divided into three stages:

• Stage IIIA, when a tumor is 5 centimeters or smaller and has spread to lymph nodes in your anus or groin.
• Stage IIIB, when anal cancer spreads to nearby organs like your vagina, urethra or bladder.
• Stage IIIC, when there’s cancer in nearby organs and it’s spread to lymph nodes near your anus or groin.

Stage IV

There’s cancer in your lymph nodes that are far away from your anus and in distant organs like your lungs or your liver.