Hi Maria,

This isn't my specialist subject (I have cancer of the oesophagus) but I do know that the HPV virus isn't solely passed on through sexual contact. I had warts and veruccas as a child, but these were passed from child to child through non-sexual contact. Some of the websites which mention anal cancer seem to  be both simplistic and almost judgemental about the possible causes - and imply assumptions in their advice on reducing risk. Like many cancers, the biggest avoidable risk is smoking. That said, CRUK figures show that 40% of cancers are avoidable - which implies that 60% of them are unavoidable. 

I hope you get a few more responses from people with appropriate experience.

Best wishes

Dave