Long-Term Outcomes after Treatment with External Beam Radiation Therapy and Palladium-103 for Patients with Higher Risk Prostate Carcinoma, Michael Dattoli, MD, Kent Wallner, MD, Lawrence True, MD, Jennifer Cash, MS, and Richard Sorace, MD, PhD. Cancer, 2003;97(4):979-983.
|Type of Study||Examined long-term outcomes for higher risk prostate cancer patients following a combined treatment with external beam radiation therapy and brachytherapy with palladium-103(using the TheraSeed® device).|
|Purpose||To determine the significance of prostatic acid phosphatase (PAP) levels in patients with higher risk, early-stage prostate cancer.|
|Issue||How effective is brachytherapy?|
|Number of Patients||161|
|Type of Patients||
|Length of Time Patients Were Followed||118 of the patients were followed more than five years.|
|Notes||Freedom from biochemical failure was defined as a serum PSA level less than or equal to 0.2 ng/mL at last follow-up.|
|Results and/or Conclusions||
Researchers studied the long-term outcome of 161 higher risk prostate cancer patients treated with a combination of brachytherapy using palladium-103 (using the TheraSeed® device) and external beam radiation therapy. Each patient had a Gleason score of 7 or more and/or a PSA level greater than 10. Patients received external beam radiation therapy followed four weeks later by brachytherapy with palladium-103.
“The biochemical cure rate was remarkably high among the 161 patients evaluated,” the researchers concluded. Actuarial analysis indicated 79% of patients are disease-free 10 years after treatment. “We are encouraged that aggressive, brachytherapy-based treatment seems to provide long-lasting biochemical disease control, even in patients with PSA levels greater than 20… Although longer follow-up is needed, the apparent plateau on the freedom from failure curve suggests that malignant prostate tumors have been eradicated rather than simply suppressed.”
The objective of the study was to address the significance of prostatic acid phosphatase (PAP) levels in predicting the return of prostate cancer following treatment of patients diagnosed with higher risk, early-stage disease. Prior to the discovery of prostate specific antigen (PSA), PAP levels were the principal factor used to measure the presence of prostate cancer in patients. Because of PSA’s greater sensitivity for detecting disease and monitoring residual prostate carcinoma, it replaced PAP measurements in the early 1990s as the principal biochemical parameter. However, recent studies indicate PAP measurements may be helpful in predicting the return of cancer. High PAP levels before treatment may indicate micrometastatic disease. According to the study, “The presence of an elevated PAP level was the strongest predictor of biochemical failure.” The researchers concluded it may be beneficial to reintroduce PAP measurements in patients who demonstrate PSA levels between 10 and 20 before treatment. Those with elevated pre-treatment PAP levels may be candidates for more aggressive radiation treatment.
Principal Investigator: Michael Dattoli, M.D., Dattoli Cancer Center and Brachytherapy Research Institute, Sarasota, Fla.