Prostate cancer can spread over time, and if a man's tumor has characteristics that indicate slow growth, he can choose active surveillance over immediate treatment. Men on active surveillance receive routine PSA blood tests and prostate biopsies and are only treated if cancer progresses or shows signs of increasing activity. However, when it comes to treatment, up to one-third of men opt-out. A new study has found that some of these men can safely put off treatment for a while.
The University of California, San Francisco researchers identified 531 men whose cancers progressed while they were under active surveillance. All of the men were initially diagnosed with Grade Group 1 prostate cancer, the lowest rung on a classification system that ranks cancers from low to high risk of aggressive spread. The biopsies of the men's tumors showed that they had moved into higher-risk grade groups, which are usually treated within an average of 25 months.
Within six months of their tumour upgrade, 192 men underwent prostate removal surgery. However, 125 men waited up to five years before having the operation, and 214 men chose not to be treated at all.
Results and observations
When the researchers compared the long-term outcomes of men who had surgery within six months to those who had to wait longer, they discovered a minimal difference. Within three years after surgery, 45 men from both groups combined had their cancer recur. However, the percentage of men who avoided a cancer recurrence was similar in both groups: 80 percent of men who had surgery early were cancer-free three years later, compared to 87 percent of men who waited up to five years to have surgery.
Furthermore, pathologist examination of prostate tissues shortly after surgery revealed similar rates of unfavorable biological characteristics that portend poorer long-term results. This sort of disease was found in nearly half of the males in both groups' tumors. Based on what they found, the authors came to the conclusion that "a subset of patients with biopsy progression can safely stay on active monitoring."
The difficulty is figuring out who those patients will be ahead of time. Unfortunately, genetic research revealed little about which males progressed more quickly than others. More research is needed, according to the authors, to see how genetic tests can help men on active monitoring make treatment decisions. In an editorial comment, Dr. Christopher Morash of the University of Ottawa noted that the three-year follow-up is insufficient and that differences between the early- and late-surgery groups may emerge in the future.
"This is an important study that continues to support active surveillance not only in men with Grade Group 1 cancers, but also in those who progress to Grade Group 2 cancers over time," says Dr. Marc Garnick, the Gorman Brothers Professor of Medicine at Harvard Medical School and Beth Israel Deaconess Medical Center, editor of the Harvard Health Publishing Annual Report on Prostate Diseases, and editor in chief of the Harvard Health Publishing Annual Report on Prostate Diseases. "New biomarker and genome findings should continue to help us figure out who can safely put off treatments and who can't, even if the disease is getting worse," the researchers said.