Six Months Hormonal Treatment in Addition to Radiotherapy Improves Survival for Men With Localized Prostate Cancer
Men with localized prostate cancer that is at risk of growing and spreading have a lower risk of disease progression and recurrence if they are treated with radiotherapy combined with androgen-deprivation therapy, according to new research. The findings, which were presented at the 33rd Conference of the European Society for Radiotherapy and Oncology in Vienna, may change clinical practice.
“Although we need longer follow-up to assess the impact on these men’s overall survival, these findings need to be taken into account in daily clinical practice. They show that three-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,” Michel Bolla, MD, a Professor of Radiation Oncology at Grenoble University Hospital, France, told conference attendees. “Therefore, during multidisciplinary team meetings to discuss a patient’s treatment, 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.”
Multicenter Trial
Dr. Bolla and colleagues from 37 centers in 14 countries recruited 819 men to a clinical trial. Patients had early-stage prostate tumors (as confirmed by analyses of biopsy samples and levels of prostate-specific antigen [PSA]) that were at intermediate or high risk of growing and spreading to other parts of the body.
Patients were randomly assigned to receive either radiotherapy alone or radiotherapy and two subcutaneous injections of luteinizing hormone-releasing hormone analogs, which lower levels of testosterone to cause reversible chemical castration. Each drug injection lasted 3 months; the first was given on the first day of irradiation and the second 3 months later. Patients took an oral antiandrogen for 15 days before the first injection in order prevent testosterone flares.
Lower Risk of Progression With Combination Regimen
Doctors chose between one of three radiation doses, 70, 74, or 78 Gy. On an average of 7.2 years follow-up, researchers found that, regardless of the radiotherapy dose and whether it was intensity-modulated or not, the 403 men who had been treated with radiotherapy combined with hormone treatment were significantly less likely to have suffered a relapse and progression of their cancer than the 407 men who had been treated with radiotherapy alone. (Nine men did not receive the planned treatment).
Men receiving the combined treatment had nearly half the risk (47%) of biochemical progression of their disease compared to men treated with radiotherapy only. In the combined treatment group, 118 men had a biochemical progression of their disease compared with 201 men in the radiotherapy only group.
Five years after their treatment, the men in the combined treatment group were doing significantly better. “They had better survival without biochemical progression,” Dr. Bolla said. “Among those receiving the combined treatment, 17.5% had progressed compared to 30.7% receiving radiotherapy alone.”
When the researchers looked at clinical progression of the disease, they found that 5 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 only.
Adverse Events
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 vs 3.6% of patients on radiotherapy alone. Problems with sexual function were higher in the combined treatment group: 27% vs 19.4%.
Dr. Bolla concluded: “These results show that, in men with localized prostate cancer that is at risk of recurring and spreading, the addition of 6 months of hormonal treatment to radiotherapy improves the time these men survive without their disease progressing. It is important to ensure that the radiation treatment is of the best quality; further clinical research is required to optimise radiation techniques and to find new hormonal treatments.”
Vincenzo Valentini, MD, President of ESTRO and a radiation oncologist at the Policlinico Universitario A. Gemelli, Rome, Italy, commented, “The results from this trial are important and practice-changing…. This option should now be considered for all these men with prostate cancer that is at risk of growing and spreading.”
The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.
