(Medical Xpress)—Contrary to the standard approach to treating metastatic prostate cancer, direct treatment of the primary tumor appears to prolong survival significantly, a new study by researchers at the University of Virginia School of Medicine and Norfolk's Eastern Virginia Medical School suggests. The surprising findings have prompted the researchers to launch clinical trials that could upend the accepted treatment of the disease.
Prostate cancer is the most common form of cancer in American men and the second-leading cause of cancer death in men. Localized prostate cancer – meaning the cancer is contained within the prostate – has a five-year survival rate of almost 100 percent. But that number drops dramatically if the cancer is metastatic, meaning it has spread beyond the prostate. In that case, five-year survival is only 28 percent.
In their new study, the researchers compared the outcomes of 250 men with metastatic cancer who received direct treatment of the tumor versus the outcomes of 8,000 who received androgen-deprivation therapy without direct treatment.
The results defied conventional wisdom on how to best treat the disease. Five-year overall survival among patients who received a radical prostatectomy, for example, was more than 67 percent, while overall survival of patients who did not receive surgery or radiation therapy was 22.5 percent.
"When we compared their survival, we noted that patients who had definitive treatment of the primary tumor had significantly improved survival compared to those who didn't," urologist Dr. Stephen H. Culp of the U.Va. Cancer Center said. "Even when we separated it based on the stage of metastatic disease, you still saw that survival advantage. Based on this, we can formulate the hypothesis that treatment of the primary tumor does affect survival in patients with metastatic prostate cancer, and therefore trials should be initiated to further examine this as an option for metastatic prostate cancer."
The researchers note in their paper that this is the first large, population-based analysis, to their knowledge, to find that prostatectomy and other primary treatments of the prostate can increase lifespan. The study did not address the best form of direct treatment for extending survival.
It's important to note that the authors stopped short of advocating that direct treatment become the norm, but instead emphasized the need for clinical trials to determine effectiveness and identify the patients most likely to benefit. They acknowledge there were limitations to their review – such as a lack of information on whether the patients had other medical conditions that could have affected mortality – that necessitate further investigation.
"We're not suggesting everyone drop the existing approaches and do this," Culp said. "We need to organize trials to figure out whether this is real."
To that end, U.Va. has launched a trial to further the pioneering research, and Eastern Virginia Medical School is organizing its trial. Other sites are in the pipeline as well. (For information on participating in U.Va.'s clinical trial, IRB No. 16946, contact Kathleen Lee at 434-924-2124.)
The study, published by the journal European Urology, quickly ignited an impassioned debate in the medical community, prompting multiple editorials in response.