Some men with prostate cancer should be offered "surveillance" rather than treatment, according to NHS guidance.
Doctors treating sufferers deemed to have "intermediate" or "low" risk prostate cancer should consider offering monitoring rather than radical surgery or radiotherapy, according to updated guidance from the National Institute for Health and Care Excellence (Nice).
Prostate cancer can be "slow growing" and many men will have cancer that will not cause them any harm in their lifetime, Nice said.
Meanwhile treatment options, including surgery and radiotherapy, can have "serious side effects", such as erectile dysfunction, fertility problems and continence.
The updated prostate cancer guidance suggests that for some men with the disease, "active surveillance " should be offered instead of extreme treatment options.
The guidance sets out a new protocol detailing how men who choose this option should be monitored with blood tests, biopsies and physical examinations, to see if and how the cancer is developing.
Prostate cancer is the most common cancer in men in the UK, with more than 40,000 cases diagnosed every year.
Professor Mark Baker, director of Nice's Centre for Clinical Practice, said: "Prostate cancer can be very slow growing and whilst many men will have a cancer that won't cause them any harm in their lifetime, nearly 10,000 men still die every year in England and Wales.
"The updated guideline includes a number of new recommendations on the swift diagnosis and treatment of different stages of the disease and a new protocol for men who choose active surveillance, which involves regular check-ups to see if and how the cancer is developing, rather than radical treatment.
"The aim of this Nice guideline is to ensure that excellent treatment is provided for men who will benefit from it."
Dr John Graham, chair of the guideline development group, added: "All treatments for prostate cancer have serious side effects which can affect the quality of life, especially their effects on erectile function, fertility and continence.
"This is why it is so important that men are able to understand the treatment options available to them and, with the support of their healthcare professional, are able to make a choice to suit their individual needs, both clinically and related to their quality of life.
"It is important that information and support is available and easily accessible to ensure patients can make the most appropriate decision for them in terms of treatment. This guideline acknowledges that, and makes recommendations about supportive care."