Prostate Cancer Treatment Challenge
Despite great improvements in medicine's ability to detect and treat prostate cancer, many men still die of the disease after undergoing treatment. To address this ongoing challenge, researchers from Brigham and Women's Hospital (BWH) and Dana-Farber Cancer Institute (DFCI) looked closely at a diagnostic tool that had not previously been studied " prostate-specific antigen (PSA) nadir " the lowest PSA level achieved after treatment for prostate cancer. Among men who relapsed (experienced PSA failure) after radiotherapy or surgery and subsequently received hormonal treatments, researchers found that those men whose PSA did not drop to an undetectable level (less than 0.2 ng/mL) had a much poorer outcome than those whose levels did drop. Details of this research are published in the September 20, 2005 issue of the Journal of Clinical Oncology.
Prostate Cancer Treatment and Symptoms
According to lead author Alexandra J. Stewart, MD, formerly of BWH and DFCI and currently with the Royal Marsden Hospital, England, "Many men with relapsed prostate cancer will still have a median survival of more than a decade after being given hormonal treatment. However some men will have shorter survival. These are the men whose PSA does not drop below 0.2 ng/mL. This indicates that PSA nadir could be used as an additional diagnostic tool to help determine the success of treatment and, if PSA nadir failure is detected earlier, it could prompt physicians to more aggressively treat the disease."
Researchers studied 747 men, ages 45 to 88 years, who were followed for up to 9.5 years. These men underwent androgen suppression therapy (AST) after they experienced rising PSA despite having had surgery or radiation therapy. Of the 28 observed prostate cancer deaths in this group, 21, or 75 percent, occurred in men whose PSA nadir was more than 0.2 ng/mL and who had a PSA doubling time of less than three months (a known indicator of aggressive disease). Patients whose PSA nadir was more than 0.2 ng/mL experienced a 20-fold increase in death from the disease. According to the researchers, this indicates that the PSA level after treatment could be an indicator of prostate cancer-specific mortality and may require more aggressive treatment including chemotherapy, specifically Docetaxel. Recent research has indicated that Docetaxel can help reduce disease among men with very advanced prostate cancer.
According to study author Anthony D'Amico, MD, PhD, chief of Genitourinary Radiation Oncology at the BWH and DFCI and professor of Radiation Oncology at Harvard Medical School, "These findings could also represent a new end-point to be used in prostate cancer clinical trials. If a new endpoint were available that were a surrogate for survival then it would be known whether a new drug has a beneficial effect much earlier."
Prostate cancer is the second most common cancer in men and the cause of approximately 30,000 deaths each year in the US. Currently, PSA testing " a simple blood test performed during a routine visit with a primary care physician " helps provide evidence that the disease is present and also indicates how aggressive it is.