Post-operative radiotherapy improves progression-free survival in prostate cancer

October 26, 2004 --Immediate post-operative radiotherapy following surgery to remove the prostate results in improved progression-free survival for prostate cancer patients, according to study results presented today by Prof. Michel Bolla of CHU de Grenoble, Grenoble, France, at the 23rd Meeting of the European Society for Therapeutic Radiation and Oncology.

Prostate cancer is the most common cancer in men, but if it is detected early enough by individual testing or mass screening, the likelihood of cure is high. Surgical removal of the prostate (prostatectomy) is one of the standard treatments for localised prostate cancer.

From 1992 onwards, radical surgeryto remove the prostate (prostatectomy) was the usual treatment for patients with early stage prostate cancer, notably those whose tumor is clinically inapparent and found incidentally (e.g. during treatment for benign disease) or where the tumour is palpable but confined within the prostate gland itself.

Dr. Bolla's randomised clinical trial investigated the effect of radiotherapy given within four months after prostatectomy versus a wait-and-see policy, following radical prostatectomy.

Trial participants had no lymph node involvement and no metastatic disease but all displayed high risk factors for local disease recurrence (e.g. capsule perforation, positive margins or involvement of seminal vesicles).

The trial ran from 1992 - 2001 and, following review by an independent data monitoring committee in December 2003 (with a median follow-up of 5 years), early disclosure of the trial results was recommended. These are the efficacy results from this trial.

Of the study group (1,005 patients), 503 men received 60Gy conventional external beam radiotherapy delivered over 6 weeks following radical prostatectomy, while the remaining 502 men received no radiotherapy following radical prostatectomy. The outcome was first measured by assessing the biological progression-free survival measured by the level of prostate specific antigen (PSA) in the blood (time to twice confirmed PSA increase over basal levels, or first clinical failure, or death).

Biological progression-free survival at 5 years was 72.2% in patients who had received radiotherapy and 51.8% in patients who had prostatectomy alone. This demonstrates a clear benefit in terms of biological progression-free survival for men who received radiotherapy treatment in addition to surgery.

Clinical progression-free survival (i.e. where the disease has not spread to other sites, or where no tumour is detectable by endo-rectal examination) was improved from 74.8% to 83.3% at 5 years in men who received radiotherapy.

These data show a statistically significant improvement in clinical progression-free survival for men who received immediate post-operative radiotherapy.

The incidence of local disease recurrence was also significantly decreased following radiotherapy. Grade 3 side effects were found to occur in less than 5% of patients in both groups making post-operative irradiation suitable for all patients. Long-term follow up of the trial patients will allow clinicians to more accurately predict the long-term benefits of immediate post-operative radiotherapy in this setting.

"Based on these results I would recommend that all men with high risk of local failure after prostatectomy should be considered for immediate post-operative radiotherapy," Prof. Bolla said. "This approach has clear benefits that outweigh the risk of side effects which occur in a small proportion of men."