There are 160,000 men with prostate cancer in the UK who cannot enjoy a full sex life, with the problem set to get worse, a charity has warned.
Men with prostate cancer are four times more likely to experience erectile dysfunction than those without, according to Macmillan Cancer Support.
An increasing number of sufferers are now receiving surgery, radiotherapy and hormone treatment, all of which can lead to issues with erectile dysfunction, according to the charity.
There are currently 250,000 men in the UK living with prostate cancer - a number set to soar to 620,000 by 2030. That could lead to there then being 390,000 men in the UK unable to get an erection.
Professor Jane Maher, chief medical officer of Macmillan Cancer Support, said: "These figures highlight a major issue facing prostate cancer patients after treatment. The sheer volume of men affected shows the need for careful discussions before treatment. Many can be helped through early intervention and better support for men living with or beyond prostate cancer.
"Macmillan has worked closely with the NHS to develop a number of services to support cancer survivors after treatment. Some are already in place, but it is vital these services are implemented across the UK so men are not left isolated with this issue."
Surgery for prostate cancer can affect the blood supply to the penis, leaving some men unable to maintain an erection. For some there is permanent damage, while the condition can be treated for other patients.
Prostate cancer survivor Jim Andrews, 63, from London, said his sex life was destroyed after he was diagnosed with cancer. He said: "My reaction when I was told I had prostate cancer was whether it would kill me. The thought of libido-killing drugs and sexual dysfunction still seemed minor in comparison to the alternative. By the time I realised I was likely to survive, my sex life had been destroyed. I was devastated. It was not a subject that any professional talked to me about. It's been a lonely journey as no one talks about it."
Macmillan's consultant clinical psychologist Dr Daria Bonanno, who helps prostate cancer patients experiencing difficulties in their sex lives, said: "For many men with prostate cancer there is a certain stigma attached to talking about erectile dysfunction. Many may feel a sense of loss of masculinity and sadness around the inability to sustain an erection and will be reluctant to seek support. This can often cause them to emotionally isolate themselves from their partners and could make the issues worse."
Macmillan is encouraging men to seek help from their GP or from Macmillan for any issues around sex and cancer.