I had surgery to remove my prostate gland. Should I also have radiation therapy to improve my chances of curing my prostate cancer? This is a common question for which we had little data to answer this concern.
Three randomized clinical trials have begun to answer this question. The trials have concluded that routinely giving post-surgical radiation does not improve outcomes after five years compared with giving radiation only if the prostate specific antigen (PSA) blood test signals a cancer recurrence. The papers about these trials were published last month in the Lancet and Lancet Oncology.
"All the surgeons have always struggled with this," said Alexander Kutikov, a urological oncologist at Fox Chase Cancer Center. "You don't want to overtreat, but you don't want to lose the window of opportunity. These trials really crystallize that you can hold off on radiation. It has changed my practice."
Claire Vale, a researcher at University College London who led one of the other trials', a meta-analysis, said the studies they analyzed could spare many men from overtreatment. "Guidelines and policy regarding the standard of care for prostate cancer should be updated based on the findings."
Prostate cancer diagnosis and treatment is fraught with risk-benefit tradeoffs. The first of these tradeoffs start in the beginning, with PSA testing to screen for prostate cancer. Current guidelines are often in conflict and are confusing.
Overall, many of the guidelines say doctors should not do routine screening without first discussing concerns that PSA testing can lead to finding and treating cancers that would never have become a threat if left alone.
However, studies suggest that up to 40% of men may be at high risk of recurrence despite surgery. That's because the cancer was aggressive, or some malignant cells escaped during surgery, or the cancer had spread to tissue near the prostate if not treated.
Numerous earlier randomized trials have tried, and failed, to definitively answer which men, if any, benefit from post-surgical radiation rather than waiting until the PSA rises. Although giving radiation sooner rather than later reduced the risk of recurrence, it did not improve survival. It did increase side effects leading to a decrease in the quality of life.
What's more, some of the studies didn't monitor the PSA level, or didn't give radiation until the cancer was advanced, or both, so the results were hard to interpret.
The three newer studies referred to earlier in this post also have limitations. For example, one of these trials enrolled men who would not usually receive post-surgical radiation because of their favorable risk profile. And the three trials varied in their use of hormones blocking drugs that fuel prostate cancer.
Also, five-year survival data for prostate cancer has not yet matured.
Ten- and fifteen-year data will provide us with a much better understanding.
"Nonetheless, these studies represent an important step forward and support" adding radiation only if the cancer comes back, wrote Derya Tilki of the University Hospital Hamburg-Eppendorf in Germany, and Anthony V. D'Amico of the Dana Farber Cancer Institute in Boston.
Data from the meta-analysis, which included 2,153 men followed for an average of five years, found that 88% of men who did not have radiation did not have a relapse, compared to 85% who had radiation soon after surgery. Among those who held off, 67% still didn't need radiation up to eight years later.
The most common reported radiation side effects in these studies was urinary incontinence, which was worse at one year for men with post-surgical radiation. And 6% of them had difficulty urinating because of damage to their urethra, compared to 4% of men who postponed radiation.
"The idea was always that you were missing an opportunity" for a cure, Kutikov said. "These studies tell me we can hold off, even in those men," at higher risk of recurrence.
