Anal Cancer can develop without a clear cause, but there are things that can increase risk:
- Age – the risk of anal cancer increases with age, particularly in people over 50
- Smoking – tobacco use is linked to a higher risk of developing anal cancer
- Immune system – people who are on immunosuppression drugs, like organ transplant recipients, or those with a weakened immune system, such as people living with HIV
- Other cancers – A history of cervical, vaginal or vulvar cancer
Anal Sex and Anal Cancer
While the vast majority of people who have anal sex won’t be diagnosed with anal cancer, the disease is slightly more common in people who engage in receptive anal intercourse (this includes cis women, trans women and men who have sex with men).
90% of anal cancers are linked to the Human Papillomavirus (HPV) infection. Around 50% of people carry HPV, but (for reasons that are not fully understood) there are a fraction of people who go on to develop cancer. HPV (in particular high-risk strains like HPV-16 and HPV-18) can lead to the development of pre-cancerous lesions known as Anal Intraepithelial Neoplasia (AIN).
Lower risk strains of HPV which cause anal warts (HPV-6 and HPV-11) and a history of transmitted infections from anal sex (STIs) are also linked to anal cancer.