A comparison of two of the most common combination therapies for locally advanced prostate cancer shows the more aggressive option is linked to a higher rate of survival.

High-risk prostate cancer, that which has continued to grow but not yet metastasized, is commonly treated with combination therapies. Each method has pros and cons, but there is little clarity on whether one might be more effective than the other.

For the first time, researchers have shown that more patients live longer if treated with the combination of prostate removal plus radiation therapy. The research was published September 25th in the journal Cancer. 

Radiation therapy

“There’s a lot of debate about whether to remove the whole prostate and follow up with radiation therapy. Or, as a second option, to spare the prostate and treat it using radiation therapy plus hormone-blocking therapy,” said senior author Grace Lu-Yao, Ph.D., Associate Director of Population Science at the Sidney Kimmel Cancer Center – Jefferson Health.

“Our study suggests that removing the prostate followed by adjuvant radiotherapy is associated with greater overall survival in men with prostate cancer,” said Lu-Yao.

The risks of prostate removal, or prostatectomy, are well known and include a higher chance of developing incontinence and erectile dysfunction. There are some risks associated with radiation treatment and hormone therapy, but they are less common and are typically thought to have a lower impact on quality of life.

“Prostatectomy is an unpopular treatment,” said Lu-Yao. “Our study showed that only six percent of men with high-risk cancer were treated with it.” It’s not just the risk of side effects.

"For some men, especially those who are not fit enough for the surgery, prostatectomy is not an option. However, this may be an option for some patients to reconsider,” said Lu-Yao.

In the largest population-based retrospective study to date, Dr. Lu-Yao and colleagues examined the records of 13,856 men in the Medicare-SEER registry diagnosed with locally advanced prostate cancer — cancer growth that had not yet metastasized to distant sites in the body.

Dr. Lu-Yao and colleagues looked at the patients who were treated either with prostatectomy plus adjuvant radiation as one group and compared them to another group who were treated with radiation therapy plus hormone-blocking therapy.

They matched the comparison groups by age, race, and comorbidity to control for factors that may influence patient outcomes, and analyzed which group did better 10 to 15 years after their procedures.

They found that  10 years after treatment, 89% of the prostate removal plus radiation group was still alive. That compared with the 74% survival at ten years in the group that received only radiation plus hormone therapy, amounting to a 15% survival advantage in the group that was treated with prostate removal.  

“For high-risk prostate patients we started the use of aggressive radiation therapy after surgery 20 years ago,” said Adam Dicker, Senior Vice President and Chair of the Department of Enterprise-Radiation Oncology at Jefferson Health, who was not involved in the study. “We recognized that it might have curative potential.”

“However, the proportion of men undergoing prostatectomy plus radiation therapy decreased significantly over time, and there were trade-offs for the survival advantages,” said Dr. Lu-Yao.  

Men who received the combination of surgery and radiotherapy had higher rates of erectile dysfunction (28% vs. 20%) and higher rates of urinary incontinence (49% vs. 19%).