07/04/2008 - Articles

Radiation after surgery improves prostate cancer survival

By: Susan Aldridge, medical journalist, PhD

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Summary

After prostatectomy, it is not clear what should be done on recurrence. A study from Johns Hopkins University now reveals that giving radiotherapy in this instance improves survival compared to 'watchful waiting'. However, the study was an observational one so has to be regarded as preliminary. It paves the way for new clinical trials that could highlight the role of radiotherapy in prostate cancer.

Introduction

There are many options for men diagnosed with prostate cancer - there is surgery (prostatectomy), hormone treatment, radiotherapy (both internal and external) and 'watchful waiting' which involves ongoing monitoring. And these approaches may be used in combination. There's a need for more information about what the best approach is for men with various stages of prostate cancer.

In the United States, 27 percent of men newly diagnosed with prostate cancer had a radical prostatectomy. Surgery is proven to control the cancer, but still 15 to 40 percent of them experience a recurrence within five years. Normally recurrence is indicated by a rise in prostate specific antigen (PSA) levels which would be revealed by routine ongoing monitoring. However, these observations do not distinguish between a local recurrence or a spread of the cancer. Nor is it known whether these men should have so-called salvage radiotherapy to try to mop up any rogue cancer cells. Another issue is whether the timing of the radiotherapy makes a difference, or whether it might be more effective in specific subgroups of men with a recurrence. These questions are really important - because 65 percent of men with these recurrences will go on to experience a spread of their cancer if left without any intervention and most of them will then die of their disease.

Recently, clinical trials have shown that adjuvant radiotherapy in men with advanced prostate cancer improves recurrence-free survival but not overall survival. Adjuvant radiotherapy is treatment given straight after surgery, rather than waiting for the recurrence. So should men who have had a prostatectomy receive adjuvant radiotherapy, or should they wait for a recurrence and have salvage radiotherapy? This is the question addressed by a study from Bruce Trock and colleagues at Johns Hopkins University.

What was done

This was a retrospective analysis of 635 men in the United States who had undergone prostatectomy between 1982 and 2004 and had experienced a recurrence. Of this group, 160 had salvage radiotherapy alone, 78 had radiotherapy and hormone therapy, while the rest did not have active treatment - they comprised the 'watchful waiting' subgroup. The researchers followed the participants to the end of 2007, recording deaths from all causes and prostate cancer.

What was found

With an average follow-up time of six years and nine years after surgery, 18 percent of the group died from prostate cancer. This figure includes 22 percent who had 'watchful waiting', compared to 11 percent who had salvage radiotherapy and 12 percent who had radiotherapy and hormone therapy. Therefore, salvage chemotherapy on its own was linked to a three-fold increase in prostate cancer-specific survival compared to those who did not have the salvage treatment. Addition of hormone treatment did not improve survival.

The benefits, however, were restricted to the men who had a rapid increase in their PSA levels within six months of their surgery. Also, starting with salvage radiotherapy more than two years after recurrence did not lead to an increase in survival. And men whose PSA level never became undetectable after salvage radiotherapy did not benefit from increased survival.

What this study means

It looks as if men who have an aggressive prostate cancer that is evidenced by higher PSA readings after surgery could benefit from having salvage radiotherapy. But this was an observational study, so it would be useful to set up a clinical trial comparing adjuvant and salvage chemotherapy among men with aggressive prostate cancer after surgery.

Source

Prostate cancer-specific survival following salvage chemotherapy vs observation in men with biochemical recurrence after radical prostatectomy
BJ. Trock, M. Han,  et al., Journal of the American Medical Association, June 18 2008, vol. 299, pp. 2760--2769

Created on: 07/04/2008
Reviewed on: 07/04/2008

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