Click here to view as PDF.Short-Term Hormone Therapy May Slow Prostate Cancer
New research suggests that a common but controversial treatment for prostate cancer reduces long-term death rates without greatly boosting patients' risk of heart problems. Researchers report that just four months of hormonal therapy before and with standard external beam radiation therapy slowed cancer growth by as much as eight years, especially the development of bone metastases. The therapy may also increase survival in older men with potentially aggressive prostate cancer. This "neoadjuvant" hormonal therapy may allow men most at risk of developing bone metastases avoid long-term hormonal therapy later on. The short-term hormonal therapy did not increase the risk of cardiovascular disease, a potential side effect of long-term hormonal therapy.
Hormonal therapy, called androgen deprivation therapy (ADT), lowers levels of cancer-fueling testosterone in the blood. It is an important treatment option for men with prostate cancer that continues to progress despite initial treatment with surgery, radiation therapy, or chemotherapy, but has been associated with side effects such as bone loss, osteoporosis, depression and an increase in cardiovascular risk factors (including blood lipids, abdominal obesity, and a syndrome associated with diabetes).
"This study demonstrates that the benefits of short-term hormonal therapy for men receiving radiation therapy for prostate cancer far outweigh the risks," said lead author Mack Roach III, MD, Professor and Chair of radiation oncology and Professor of urology at the University of California, San Francisco. "While four months of hormonal therapy isn't enough to cause significant side effects, we found that it can delay the development of bone metastasis by as many as eight years, which is very significant." The study has being published in the Journal of Clinical Oncology
(Short-Term Neoadjuvant Deprivation Therapy and External Beam Radiotherapy for Locally Advanced Prostate Cancer: Long-Term Results of RTOG 8610 a Phase III Prospective Randomized Trial. Mack Roach, III, et al).
Starting in 1987, Radiation Therapy Oncology Group researchers studied 224 men with high-risk prostate cancer who received ADT (goserelin and flutamide) before and concurrent with external beam radiation therapy, and 232 men with the disease who received radiation therapy alone. After 13 years of follow up, they found better 10-year disease-specific death rates (the rate of death from prostate cancer) for men who received ADT plus radiation (23% versus 36% of the radiation-only group), disease metastasis rates (35% versus 47%), disease-free survival (the percentage of men free of cancer at 10 years; 11% versus 3%) and biochemical failure rates (a rise in prostate-specific antigen levels; 65% versus 80%).
Among men who received neoadjuvant hormonal therapy, there was up to an eight-year delay in the time it took 40% of patients to develop bone metastases compared with men receiving radiation alone. Men who develop bone metastases often require long-term hormonal therapy, which can increase their risk for side effects. "So by taking a little bit of hormonal therapy early, patients may avoid having to take a lot of it later," added Dr. Roach. Fatal cardiac events occurred in 12% of patients in the ADT group compared with 9% of the radiation-only group—a difference that was not statistically significant.
Adapted from materials provided by American Society of Clinical Oncology.Interdisciplinary Prostate Cancer Congress
Meeting to be held in New York City on March 8, 2008
Prostate cancer is the most common cancer in American men, other than skin cancers, and the second leading cause of cancer death in this population. The American Cancer Society estimated that during 2007 approximately 219,000 new cases of prostate cancer would be diagnosed and about 27,000 men in the United States would die of the disease. Attributable to modern forms of early detection and treatment, more than nine out of 10 prostate cancers are found in the local and regional stages (local indicates the cancer is confined to the prostate while regional means it has spread from the prostate to nearby areas but not to distant sites such as bone). When compared with men of the same age and race who do not have cancer, the five-year relative survival rate for these local and regional diagnosed patients is nearly 100%. According to the Cancer Trends Progress Report (www.progressreport.cancer.gov), it is estimated that nearly $8 billion dollars is spent annually on prostate cancer treatment. The effect of prostate cancer on men in the United States as well as in health care costs underscores the need for continued advances in detection and treatments for this disease as well as the continued need to reinforce the knowledge and skills of practitioners who manage the treatment of prostate cancer.