April 9, 2014 - Men with early stage prostate cancer that is at risk of growing and spreading have a lower risk of relapse if treated with 6 months of hormone suppressants in addition to radiotherapy, suggests preliminary research presented to the annual European Society for Radiotherapy and Oncology in Vienna yesterday.
Lead researcher, Michel Bolla, Professor of Radiation Oncology at Grenoble University Hospital, France, said, “They show that 3-dimensional conformal radiotherapy, whether intensity modulated or not, and regardless of the dose level, has to be combined with short-term androgen deprivation therapy in order to obtain a significant decrease in the risk of relapse. This combined treatment approach should be one of the options proposed for men with localized prostate cancer that has an intermediate or high risk of growing and spreading.”
Their findings are based on 819 men with early stage prostate cancer, confirmed by biopsy and levels of prostate specific antigen, from 37 centers in 14 countries. Their tumors were at intermediate or high risk of growing and spreading to other parts of the body. They were randomly assigned to receive either radiotherapy alone or radiotherapy and two injections under the skin of luteinizing hormone-releasing hormone analogues (LH-RH analogues), which lower levels of testosterone to cause reversible chemical castration.
Each drug injection lasted three months; the first was given on the first day of irradiation and the second three months later. To prevent the ‘flare’ effect on testosterone levels of LH-RH analogues, the men took an oral anti-androgen (bicalutamide, 50 mg a day) for 15 days before the first injection.
Doctors could choose between one of three irradiation doses of 70, 74 or 78 Grays. They monitored the men for an average of just over 7 years and found that, regardless of the radiotherapy dose and whether it was intensity modulated or not, the 403 men given the combination treatment fared better than the 407 men who had been treated with radiotherapy alone.
Those given the combination had nearly half the risk (47%) of their disease progressing as those treated with radiotherapy alone. And biochemical progression occurred in 118 men given the combination treatment compared with 201 men given radiotherapy alone.
Five years after completing treatment, the men in the combined group were doing significantly better. “Among those receiving the combined treatment, 17.5% had progressed compared to 30.7% receiving radiotherapy alone,” said Professor Bolla.
When the researchers looked at clinical progression of the disease, they found that five years after their treatment 88.7% of the men in the combined treatment group had not progressed, compared with 80.8% of men receiving radiotherapy alone.
So far, 152 patients have died, of which 25 died from prostate cancer. Side-effects, relating mainly to problems with urination, were seen in 5.9% of patients receiving the combined treatment compared with 3.6% of patients on radiotherapy alone. Problems with sexual function were also higher in the combined treatment group: 27% compared with 19.4%.
“These results show that in men with localised prostate cancer that is at risk of recurring and spreading, the addition of six months of hormonal treatment to radiotherapy improves the time these men survive without their disease progressing,” commented Professor Bolla, adding that it was important to ensure that the radiotherapy was of the highest quality.
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