Men with incurable prostate cancer halve their risk of death if given hormone therapy and radiotherapy, a new study found.
The longitudinal Nordic study found men given a combination of treatments halved the risk of patients dying from prostate cancer from 34 to 17 per cent over 15 years.
Their survival was prolonged by 2.4 years compared to those just receiving hormone therapy.
Prostate cancer is the most common cancer in British men with over 40,000 new cases diagnosed every year.
If diagnosed early the chances of survival are generally good.
Nine in ten men diagnosed with localised prostate cancer and locally-advanced prostate cancer known as Stage 1 and 2 will live at least five more years and 65 to 90 per cent will live for at least 10 more years.
If the cancer has spread from the prostate and may have grown into the tubes that carry semen, known as stage 3, there is a 70 to 80 per cent of chance of living for at least five more years.
But if the cancer is aggressive and spread into the lymph nodes or another part of the body there is only a 30 per cent chance of living for at least five more years.
Between two and three in ten men are diagnosed at this stage.
Hormone therapy does not cure the cancer but slows the progression of advanced prostate cancer and relieve symptoms.
Cancer cells need testosterone to grow so the therapy blocks the effects of testosterone.
This is done either by injections to stop the body making testosterone, called luteinising hormone-releasing hormone (LHRH) agonists, or tablets to block the effects or reduce the production of testosterone, called anti-androgen treatment.
Radiotherapy uses radiation to kill cancerous cells, curing localised and locally-advanced prostate cancer or slowing the progression of metastatic prostate cancer.
Professor Dr Anders Widmark said: “Before the turn of the century, it was tradition to castrate men with high-risk or aggressive local prostate cancer with no signs of spreading, as the disease at that point was thought to be incurable.
“When we published the first results of this study in the Lancet in 2009, we contributed to changing the attitude towards radiotherapy for older patients with advanced prostate cancer.
“In this follow-up study, we present even more evident results that clearly show how patients who previously were considered incurable, to a large extent can be cured and that these patients should therefore be offered radiotherapy as an additional treatment.”
The study published in European Urology compared a common Nordic pill-based hormone therapy with antiandrogen and the same treatment method with the addition of local radiotherapy.
It involved 875 patients treated for locally advanced prostate or aggressive prostate cancer at around 40 clinics in Sweden and Norway from 1996-2002 and then continued to follow the patients.
They were either given just hormone therapy or hormone therapy and radiotherapy.
Prof Anders added: “In patients with nonmetastatic locally advanced or aggressive prostate cancer, endocrine treatment and radiotherapy reduces the absolute risk of prostate cancer-specific death by 17 per cent at 15 years compared with endocrine treatment alone.
“The comparable 15 year prostate cancer-specific mortality rates being 17 per cent and 34 per cent.
“We are also in the process of evaluating how hormone therapy against prostate cancer affects the patients’ quality of life.
“We will publish that study shortly.”