Negative biopsies among early-stage prostate cancer patients who've chosen active surveillance are associated with a low risk of disease progression, but they aren't a sign that their cancer has completely vanished, a new study indicates.
Active surveillance refers to close monitoring for signs of cancer progression -- what's often called "watchful waiting." Patients sometimes get regular prostate-specific antigen (PSA) testing, prostate exams, imaging and repeat biopsies.
The objective of active surveillance is to avoid or delay treatment and its side effects without putting patients at risk of cancer progression and death.
Sometimes, active surveillance patients have negative biopsies that show no evidence of prostate cancer. While some of these patients may believe that their cancer has "vanished," they most likely have low-volume or limited, hidden areas of prostate cancer that weren't detected in the biopsy sample, according to the authors of the study published recently in The Journal of Urology.
"While a negative biopsy is good news, the long-term implications associated with such 'hidden' cancers remain unclear," said study author Dr. Carissa Chu, from the University of California, San Francisco.
For the study, Chu and colleagues analyzed data from 514 men undergoing active surveillance for early-stage prostate cancer between 2000 and 2019. All of them had at least three surveillance biopsies after their initial prostate cancer diagnosis. Median follow-up time was nearly 10 years.
Of those patients, 37% had at least one negative biopsy, including 15% with consecutive negative biopsies, according to the report.
Men with negative biopsies had more favorable disease characteristics, including low PSA density and fewer samples with cancer at the initial prostate biopsy. Negative biopsies were also associated with good long-term outcomes, the researchers said.
After 10 years, rates of survival with no need for prostate cancer treatment (such as surgery or radiation) were 84% for men with consecutive negative biopsies, 74% for those with one negative biopsy and 66% for those with no negative biopsies.
After adjusting for other factors, the researchers concluded that men with one or more negative biopsies were much less likely to have cancer detected on a later biopsy.
"For men undergoing active surveillance, negative biopsies indicate low-volume disease and lower rates of disease progression," Chu said in a journal news release. "These 'hidden' cancers have excellent long-term outcomes and remain ideal for continued active surveillance."
There's more on prostate cancer at the U.S. National Cancer Institute.
SOURCE: The Journal of Urology, news release, Nov. 17, 2020