Anal cancer develops when abnormal cells grow uncontrollably in the tissues of the anus, the opening at the end of the digestive tract where stool leaves the body. Although relatively rare, its incidence has been increasing in recent decades, with persistent infection from high-risk human papillomavirus (HPV) identified as the primary cause.

The most common type is squamous cell carcinoma, which arises from the cells lining the anal canal. Less common types include adenocarcinoma, melanoma, and neuroendocrine tumors.

At OncoClinic, we support you with appropriate diagnostics, clear explanations, and a personalized care plan tailored to your diagnosis, overall health, and goals.

Signs and symptoms

• Rectal bleeding
• Pain or pressure in the anal area
• A lump or mass near the anus
• Anal itching
• Changes in bowel habits
• Discharge from the anus
• Narrowing of stools
• Other symptoms can include enlarged lymph nodes in the groin, difficulty controlling bowel movements, and fatigue or unintended weight loss

Persistent anal symptoms should be evaluated by a healthcare professional.

Risk factors

• Age: Older age, though it can occur in younger individuals
• HPV infection: Persistent HPV infection, especially HPV-16 (most important risk factor)
• Immune system: Weakened immune system, including HIV infection or immunosuppressive therapy
• Cancer history: History of cervical, vulvar, vaginal, or penile cancer
• Sexual activity: Anal intercourse and multiple sexual partners (related to HPV exposure)
• Tobacco use: Smoking
• Chronic conditions: Chronic anal inflammation or fistulas (less common)

Screening

There is no routine population-based screening for anal cancer in the general population.

Screening methods in high-risk groups may include:

• Anal cytology (anal Pap test)
• High-resolution anoscopy, when abnormalities are detected

Screening recommendation

Targeted surveillance may be considered for individuals at higher risk, such as:

• People living with HIV
• Individuals with a history of HPV-related cancers
• Organ transplant recipients or others who are immunosuppressed

Screening strategies should be individualized and discussed with a healthcare provider.

Diagnosis

Anal cancer is usually diagnosed after symptoms prompt evaluation or abnormal screening results.

Diagnostic evaluation typically includes:

• Physical examination, including digital rectal exam
• Anoscopy or proctoscopy, allowing direct visualization of the anal canal
• Biopsy, to confirm the diagnosis and determine tumor type
• HPV testing, in selected cases

Staging

Once anal cancer is confirmed, staging determines how far the disease has spread and helps guide treatment.

Staging evaluation may include:

• CT or MRI scans of the pelvis and abdomen
• PET/CT scan to assess lymph nodes and distant spread
• Assessment of inguinal (groin) lymph nodes

Anal cancer staging:

Anal cancer is staged from Stage I to Stage IV:

• Stage I: Small tumor confined to the anus
• Stage II: Larger tumor, still limited to the anal region
• Stage III: Cancer has spread to nearby lymph nodes
• Stage IV: Cancer has spread to distant organs such as the lungs or liver

Treatment and procedures

At our clinic, anal cancer care is delivered through a multidisciplinary, patient-centered approach. Treatment is tailored based on cancer stage, tumor characteristics, and overall health.

Chemoradiation: The standard treatment for most anal cancers is a combination of chemotherapy and radiation therapy, which can often cure the disease while preserving anal function.

Systemic therapy: Chemotherapy or immunotherapy may be used for advanced or metastatic disease.

Surgery: Surgery is usually reserved for cases where cancer does not respond completely to chemoradiation or for recurrent disease. When surgery is indicated, procedures are performed at our accredited partner hospitals, under the direct coordination and supervision of our medical team, ensuring continuity of care.

Palliative and Supportive Care: Supportive care focuses on symptom control, pain management, nutritional support, emotional well-being, and quality of life at all stages of disease.

References

Anal cancer overview

American Cancer Society, 2026

Anal cancer – patient version

National Cancer Institute (NCI), 2026

NCCN clinical practice guidelines in oncology: anal carcinoma

National Comprehensive Cancer Network (NCCN), latest version