The study addresses an important question for men newly diagnosed with prostate cancer and at minimal risk of cancer progression or metastases: when to actively treat versus when to observe and closely monitor. Radiation therapy and surgery are effective treatments but can be associated with serious long-term side effects such as incontinence and erectile dysfunction.
Investigators in the study show that two separate biopsies are needed to determine optimal selection of patients for active surveillance, also known as "watchful waiting" when patients decide not to undergo immediate treatment.
Study author Scott Eggener, MD, assistant professor of surgery at the University of Chicago Medical Center, notes there are no widely-accepted recommendations on which patients are appropriate candidates for active surveillance or when to perform second or "restaging" biopsies. The authors show that a restaging biopsy provides doctors with additional information regarding the cancer and is the best way to ensure the short-term success of active surveillance.
"When or if to treat men with low-risk prostate cancer has always been a challenging question that faces patients and urologists," Eggener says.
"Some men may be rushing into treatment that won't necessarily benefit them, prevent problems, or prolong life. Close observation in certain patients may provide and maintain quality of life without increasing the chances of the cancer spreading," he says.
The study suggests that before electing active surveillance, it is important for patients to undergo a restaging biopsy following the initial diagnostic biopsy. A similar study released last year by many of the same authors found that approximately 30 percent of patients were no longer appropriate candidates for active surveillance following a restaging biopsy.
Eggener adds that the study was precipitated by the estimated 20-50 percent of men diagnosed with prostate cancer in the U.S. who will eventually die from another cause, but not from their prostate cancer. This represents a large number of men who do not benefit from treatment.
The study conducted between 1991 and 2007 involved 262 men from four hospitals in the U.S. and Canada who met the following criteria: under age 75; prostate-specific antigen (PSA) below 10 ng/ml; clinical stage T1-T2a; Gleason score 6 or below; and 3 or fewer positive cores at diagnostic biopsy. In addition, participants underwent a restaging biopsy and had no treatment for six months following the repeat biopsy. They subsequently underwent physical exams and PSA tests every six months with biopsies recommended every 1-2 years.
Of that initial pool electing surveillance of their cancer, 43 patients eventually chose treatment or had evidence of cancer progression prompting recommendation of treatment by their physician. Following delayed treatment (radiation or surgery,) all but one were cured of their cancer. The remaining 219 patients remained on active surveillance without evidence of metastases.
"Active surveillance with delayed treatment, if necessary, for select patients appears to be safe and associated with a low risk of metastatic spread," the study concludes.
Unlike many past studies on active surveillance that used data before PSA tests were widely available, this multi-center study is based on patients who were screened with the PSA blood test. The PSA test is a widely used cancer screening tool that predicts a man's chances of having prostate cancer.
"Active surveillance is not a total disregard for patients with prostate cancer. Instead, it identifies men unlikely to be affected by their cancer and encourages frequent monitoring, and then starting therapy at a later appropriate time if needed. Cure rates appear to be identical when these men choose immediate treatment or delayed treatment when prompted by new information about their condition," Eggener says.