Diagnostic Process

If you or your healthcare provider suspect anal cancer due to symptoms or risk factors, the next step is a series of tests. Identifying anal cancer early can significantly improve outcomes. Diagnosis typically involves biopsy, physical exams, imaging to assess abnormalities.

Physical Exams

The screening and diagnostic process often starts with a physical exam, allowing the healthcare provider to detect visible or felt abnormalities in the anal area. These exams are quick, usually performed in a doctor’s office, and though they may feel invasive, they are generally not painful.

• Digital Rectal Exam (DRE): A provider inserts a gloved, lubricated finger into the rectum to feel for lumps, swelling, sphincter tone, or other abnormalities.

• Anoscopy & Proctoscopy: If needed, your doctor may use a small, lighted tube to take a closer look inside the anal canal.

• Inguinal Lymph Node Examination: This is a physical check of the lymph nodes in the groin area to see if they are swollen, enlarged, or firm.

Tests to Confirm a Diagnosis

If physical exams show something abnormal, further testing can help determine if changes are benign (i.e. precancerous) or malignant (i.e. cancerous).

• Anal Pap Smear: This test is similar to a cervical Pap test. The provider collects cells from the anal canal with a small swab, which are then examined for abnormal or pre-cancerous cells. This test is especially recommended for high-risk individuals, such as men who have sex with men (MSM), HIV-positive individuals, and people with a history of HPV.

• High-Resolution Anoscopy (HRA): If an anal Pap smear shows abnormal results, the provider may suggest an HRA. This procedure uses a magnifying device to closely examine the anal canal, helping the provider spot small or hard-to-see lesions. HRAs are often performed by specialists trained in this technique.

• Biopsy: If screening detects suspicious cells or growths, the provider may perform a biopsy. This involves removing a small sample of tissue from the abnormal area, which is then analyzed for cancer cells. A biopsy is the only way to confirm an anal cancer diagnosis. Local anesthesia may be used to minimize discomfort, and results are usually available within a few days.

What to Expect: Screening tests, especially biopsies, may require a short office visit or a referral to a specialist. Although biopsies may cause mild discomfort, they provide crucial information for an accurate diagnosis.

Understanding the Extent of the Cancer

If a biopsy confirms anal cancer, imaging tests help determine the stage and extent of the cancer. Imaging tests are generally painless, but may take more time than anticipated. Some scans may require contrast dye injections, which can cause a warm sensation or metallic taste. Your provider will explain each test in detail and let you know what to expect.

• Computed Tomography (CT) Scan: A CT scan uses high energy photons to create detailed cross-sectional images of the body. You’ll lie on a table that slides into a circular scanner, which takes images of the pelvic area, abdomen, and lymph nodes. Sometimes, an iodine-based contrast dye is used to improve clarity.

• Magnetic Resonance Imaging (MRI): MRI uses magnets and radio waves to create detailed images of soft tissues. Compared to CT, MRI can provide a more clear image of the soft tissues around the anus and rectum. You’ll lie still in a tube-like machine that takes multiple images, and a contrast dye (not iodine based) may be used to enhance the images. Due to the use of magnets, you will not be able to wear anything metal during this procedure.

• Positron Emission Tomography (PET) Scan: A PET scan detects areas of high metabolic activity, which can indicate cancer. Before the scan, you’ll receive a small injection of radioactive glucose. Cancer cells in addition to other cell types (e.g. cell of the heart) use more glucose, allowing the scan to detect  cancer.

What to Expect: Imaging tests are generally painless, but some, like PET or MRI scans, may take longer. Some scans may require contrast dye injections, which can cause a warm sensation or metallic taste. Your provider will explain each test in detail and let you know what to expect.

Putting It All Together

The diagnostic process for anal cancer includes physical exams, screening tests, and imaging to evaluate symptoms and confirm the diagnosis. By combining these methods, healthcare providers can accurately diagnose anal cancer, assess its stage, and create an effective treatment plan.

If you experience symptoms like rectal bleeding, pain, lumps, itching, or changes in bowel movements, consult a healthcare provider. Early detection is key, and understanding each step in the diagnostic process can help you feel informed and empowered on your healthcare journey.