Anal Cancer: Symptoms, Causes, Types, Stages, Treatment and Prevention  

Introduction

Noticing rectal bleeding, persistent anal discomfort, or changes in your bowel habits can be concerning. However, these symptoms do not always mean that something is wrong, as they can have several causes. In some cases, though, they may point to a rare type of cancer, the anal cancer¹.  

This blog will discuss anal cancer in detail. It will cover the anal cancer symptoms, causes, types, stages, management options, and prevention of anal cancer. 

What Is Anal Cancer?

Anal cancer is a type of cancer that develops in the tissues of the anus (which is the external opening through which stool is excreted from the body). The anus is located at the end of the digestive tract and connects to the rectum (the last part of the large intestine). It is surrounded by ring-like muscles called sphincters that help control the passage of stool². 

Anal cancer can develop in different types of cells in and around the anus. Most cases begin in the cells (mucosa) of the lining of the anal canal or the skin around the anus (perianal skin)². The type and location of the cancer can help doctors determine an appropriate treatment plan. 

Types of Anal Cancer

Anal cancer can be classified based on where it develops and the type of cells involved. The main types include⁶: 

• Squamous Cell Carcinoma: Squamous cell carcinoma is the most common type of anal cancer. It develops from the squamous cells that line most of the anal canal and the skin around the anus. 
• Adenocarcinoma: Adenocarcinoma is a rare type of anal cancer that develops from glandular cells in the upper part of the anus or from glands beneath the anal lining.  
• Basal Cell Carcinoma: Basal cell carcinoma is a rare type of skin cancer that can develop in the skin around the anus (perianal skin).  
• Melanoma: Anal melanoma is a very rare cancer that develops from pigment-producing cells called melanocytes.  
• Gastrointestinal Stromal Tumour (GIST): GISTs are tumours that usually develop in the stomach or small intestine but can very rarely occur in the anal region.  
• Lymphoma: Anal lymphoma is extremely rare and develops from lymphatic tissue (a network of tissues, vessels, and organs) in the anal region. 

Symptoms of Anal Cancer

Anal cancer may not cause any noticeable symptoms in its early stages. When anal cancer symptoms  do occur, they may include^1,7: 

• Pain, discomfort, or pressure around the anus 
• Persistent itching around the anal area 
• Mucus or other discharge from the anus 
• Changes in bowel habits (such as more frequent or loose stools) 
• Bleeding from the anus or rectum 
• A lump or growth in/around the anus 

Important: Many of these anal cancer symptoms can also occur with common conditions such as haemorrhoids (piles), fistulae or anal fissures⁷. Therefore, if you have any concerning symptoms, consult a doctor. 

Causes of Anal Cancer

Anal cancer develops when changes in the DNA of cells in or around the anus cause them to grow and divide abnormally⁸. Although the exact anal cancer causes are not always known, most anal cancers are linked to infection with HPV⁹. 

HPV is a common infection that can spread through skin-to-skin contact in the genital area and through sexual contact, including vaginal, anal, or oral sex. It can also be transmitted through sharing sex toys⁹. HPV may cause benign warts (non-cancerous growths on skin) in most individuals, but persistent infection with certain high-risk types (like types 16 and 18) can lead to cell changes that may eventually develop into anal cancer¹⁰. 

Risk Factors for Anal Cancer

Certain factors could increase a person’s risk of developing anal cancer. These include^1,9: 

• Weakened immune system: Conditions such as HIV or long-term use of medicines that suppress the immune system (including after an organ transplant) can increase the risk. 
• Previous HPV-related cancers: A history of cervical, vaginal, or vulvar cancer may increase the risk of anal cancer. 
• Certain sexual practices: Having unsafe anal sex or multiple sexual partners can increase the likelihood of HPV infection, which may raise the risk of anal cancer. 
• History of anal warts or sexually transmitted infections: These may be associated with a higher risk of anal cancer. 
• Smoking: Cigarette smoking is linked to an increased risk of anal cancer, particularly among people who currently smoke. 

How Is Anal Cancer Diagnosed?

If anal cancer is suspected based on symptoms or a physical examination, your doctor may recommend several tests to examine the anus and rectum. These tests help identify abnormal areas and confirm whether cancer is present. Common tests used to diagnose anal cancer include^1,11: 

• Digital rectal examination (DRE): A gloved, lubricated finger is gently inserted into the rectum and anal canal to check for lumps, swelling, or other unusual changes. 
• Anoscopy: A short, lighted instrument called an anoscope is inserted into the anus to examine the anal canal and lower rectum.  
• Proctoscopy: A thin, lighted instrument called a proctoscope is used to examine the anus and rectum for abnormal areas. 
• Endo-anal or endorectal ultrasound: An endoscopic ultrasound probe is inserted into the anus or rectum to create images of the surrounding tissues and help assess the extent of an abnormal growth. 
• Biopsy: If an abnormal area is found, a small tissue sample may be removed during an examination and examined under a microscope. A biopsy is usually needed to confirm a diagnosis of anal cancer. 

Stages of Anal Cancer

The stage of anal cancer describes how large the tumour is and whether the cancer has spread to nearby lymph nodes, organs, or other parts of the body. Doctors usually use the following staging system to determine the stage, which is then classified from Stage 0 to Stage IV (mentioned below)¹². 

• Stage 0: Abnormal cells are found in the innermost lining (mucosa) of the anus. These cells may become cancerous and spread to nearby tissues.  
• Stage I: Cancer has formed, but the tumour is 2 cm or smaller. 
• Stage II: Stage II is divided into two groups: 
  • Stage IIA: The tumour is larger than 2 cm but not larger than 5 cm. 
  • Stage IIB: The tumour is larger than 5 cm. 
• Stage III: Stage III is divided into IIIA, IIIB, and IIIC, depending on the tumour size, spread to nearby organs, and involvement of nearby lymph nodes. 
  • Stage IIIA: The tumour is 5 cm or smaller and has spread to lymph nodes near the anus or groin. 
  • Stage IIIB: The tumour may be any size and has spread to nearby organs such as the vagina, urethra, or bladder, but not to lymph nodes. 
  • Stage IIIC: The tumour may be any size and may have spread to nearby organs, with cancer also present in lymph nodes near the anus or groin. 
• Stage IV: The tumour can be any size and may have spread to nearby lymph nodes or organs. It has also spread to distant parts of the body, such as the liver or lungs. 

Treatment of Anal Cancer

If you are wondering if anal cancer is curable, the answer depends on factors such as its stage, type, and response to treatment. 

Depending on your overall health, your doctor may involve one or more approaches, such as surgery, radiation therapy, or chemotherapy. The main anal cancer treatment/management options include¹³: 

• Surgery: Surgery may be used to remove small tumours. It removes the tumour along with some surrounding healthy tissue while preserving other muscles and organs.  
• Radiation therapy: Radiation therapy uses high-energy radiation to destroy cancer cells or stop them from growing. It may be given externally or, in some cases, internally. 
• Chemotherapy: Chemotherapy uses medicines that kill cancer cells or stop them from dividing. Drugs (such as capecitabine, cisplatin, fluorouracil, and mitomycin) may be used sometimes in combination with radiation therapy. 

Possible Complications of Anal Cancer

Anal cancer can lead to complications, particularly when it is diagnosed at an advanced stage or spreads to nearby tissues or other parts of the body. Possible complications include¹⁴: 

• Persistent pain or bleeding 
• Spread to nearby lymph nodes 
• Invasion of nearby organs, such as the bladder, urethra, or vagina 
• Distant spread (metastasis) to other parts of the body 
• Recurrence after treatment 

Can Anal Cancer Be Prevented?

Anal cancer cannot always be prevented, but you can lower your risk with healthy lifestyle choices and HPV prevention. Common anal cancer prevention steps include^1,9: 

• Get the HPV vaccine: HPV vaccination is one of the most effective ways to reduce the risk of anal cancer and other HPV-related cancers. 
• Practice safer sex: Limiting the risk of HPV infection through safer sexual practices can help reduce your risk. 
• Avoid smoking: Quitting smoking lowers the risk of anal cancer and supports overall health. 
• Manage conditions that weaken the immune system: People with HIV or other conditions affecting immunity should follow regular medical care and recommended screening. 
• Get regular screening when recommended: People at higher risk, including adults with HIV, may benefit from regular anal cancer screening.  

When Should You Consult a Doctor?

You should see a doctor if^1,7: 

• You have anal cancer symptoms, such as bleeding, pain, itching, discharge, or a lump around the anus. 
• You notice any new or unusual change (including any skin changes) around your anus that does not go away. 
• Your symptoms persist or get worse, even if you think they may be due to haemorrhoids or an anal fissure. 
• You have unexplained changes in your bowel habits, such as frequent or loose stools or difficulty controlling bowel movements. 
• You have risk factors for anal cancer, such as a weakened immune system, a history of HPV infection, or a previous history of cervical, vaginal, vulvar, or anal cancer. 

Also Read: ​​Prostate Cancer: Causes, Early Signs, Treatment Options & How to Lower Your Risk 

Conclusion

Anal cancer is rare, but recognising its symptoms and understanding its risk factors can help with early detection and timely treatment. Since most cases are linked to high-risk HPV infection, HPV vaccination is an important preventive measure.  

If you notice persistent bleeding, pain, itching, a lump, or other unusual changes around the anus, consult a doctor for evaluation. Anal cancer can often be managed effectively, especially when detected early, with appropriate diagnosis and treatment. 

Frequently Asked Questions (FAQs)

References

1. Anal Cancer. Medline. Accessed August 28, 2026.  https://medlineplus.gov/analcancer.html 

2. What Is Anal Cancer? NCI. March 9, 2026. Accessed August 28, 2026. https://www.cancer.gov/types/anal/what-is-anal-cancer  

3. Gondal TA, Chaudhary N, Bajwa H, Rauf A, Le D, Ahmed S. Anal Cancer: The Past, Present and Future. Curr Oncol. 2023;30(3):3232-3250. doi:10.3390/curroncol30030246. https://pubmed.ncbi.nlm.nih.gov/36975459/ 

4. Siegel R, Niklas Werner R, Koswig S, Gaskins M, Rödel C, Aigner F. Anal Cancer—Diagnosis, Treatment and Follow-Up. Dtsch Ärztebl Int. 2021;118(13):217-224. doi:10.3238/arztebl.m2021.0027. https://pmc.ncbi.nlm.nih.gov/articles/PMC8572542/ 

5. Sathishkumar K, Chaturvedi M, Das P, Stephen S, Mathur P. Cancer incidence estimates for 2022 & projection for 2025: Result from National Cancer Registry Programme, India. Indian J Med Res. 2022;156(4-5):598-607. doi:10.4103/ijmr.ijmr_1821_22. https://pubmed.ncbi.nlm.nih.gov/36510887/  

6. Anal Cancer. American Cancer Society. Accessed August 28, 2026. https://www.cancer.org/cancer/types/anal-cancer.html  

7. Symptoms of anal cancer. NHS. March 28, 2024. Accessed August 28, 2026. https://www.nhs.uk/conditions/anal-cancer/symptoms/  

8. Causes & Risk Factors. NCI. March 9, 2026. Accessed August 28, 2026. https://www.cancer.gov/types/anal/causes-risk-factors  

9. Causes of anal cancer. NHS. March 28, 2024. Accessed August 28, 2026. https://www.nhs.uk/conditions/anal-cancer/causes/  

10. Ebrahimi F, Rasizadeh R, Jafari S, Baghi HB. Prevalence of HPV in anal cancer: exploring the role of infection and inflammation. Infect Agent Cancer. 2024;19:63. doi:10.1186/s13027-024-00624-0. https://pubmed.ncbi.nlm.nih.gov/39696546/  

11. Diagnosis & Prognosis. NCI. March 19, 2026. Accessed August 28, 2026. https://www.cancer.gov/types/anal/diagnosis-prognosis  

12. Stages of Anal Cancer. NCI. March 9, 2026. Accessed August 28, 2026. https://www.cancer.gov/types/anal/stages  

13. Treatment for Anal Cancer. NCI. March 9, 2026. Accessed August 28, 2026. https://www.cancer.gov/types/anal/treatment  

14. Ramos Santillan V, Kaur A, Menon G, Babiker HM, Cagir B. Anal Carcinoma. In: StatPearls. StatPearls Publishing; 2026. Accessed August 28, 2026. http://www.ncbi.nlm.nih.gov/books/NBK441891/  

15. Piles (haemorrhoids). NHS. Accessed August 28, 2026. https://www.nhs.uk/conditions/piles-haemorrhoids/  

16. Anal Cancer Causes, Risk Factors, and Prevention. American Cancer Society. Accessed August 28, 2026. https://www.cancer.org/cancer/types/anal-cancer/causes-risks-prevention.html  

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