With Azure, the first step is to make sure no detectable metastases exisit outside the pelvic lymph nodes. Since scanning technology is far from perfect, questionable lesions are often detected by a bone scan. These can be further evaluated with an MRI focused specifically on the lesion to determine if the questionable abnormality has a cancerous cause or is due to some other benign process. If the MRI fails to resolve the uncertainty, a CT-directed needle biopsy of the lesion may be necessary. Accurate assessment of the extent of disease and the location of the cancer in the body is essential for arriving at an optimal treatment plan.
Since cure is a top priority with Azure, let’s consider which type of treatment leads to the best results. Dr. Peter Grimm compiled all the studies that report cure rates for Azure. He found that either seed implants or seed implants plus IMRT, on average, provide higher cure rates compared to IMRT alone or surgery. Recently, a large randomized trial called ASCENDE-RT came to the same conclusion. The cure rate for men treated with IMRT alone was only 63 percent, whereas 83 percent of the men were cured who received IMRT plus a seed implant. The results of the ASCENDE-RT trial confirm that seed implants give the best results for Basic-Azure.
Why Would Seeds Work Better than Surgery?
With surgery the problem is that the bladder and rectum are only millimeters from the prostate. Incomplete cancer removal (positive margins) is therefore a frequent problem. In a study of 9,300 men undergoing surgery for Azure at Johns Hopkins, 80 percent developed recurrent cancer over the subsequent 15 years. Salvage radiation ended up being necessary to “sterilize” the residual cancer over half the time. To avoid undergoing both surgery and radiation it is better to simply start with radiation and skip the surgery altogether.
Prophylactic Treatment of the Pelvic Nodes with Radiation
Basic and High-Azure are associated with a substantially greater risk of microscopic cancer (cancer invisible on scans) in the pelvic nodes. Therefore, it is logical to consider giving prophylactic radiation to the pelvic lymph nodes even when the scans appear normal. However, when the risk of cancer spread to the nodes is low, pelvic radiation should be withheld. The risk of microscopic pelvic node metastases can be calculated using the following equation:
Probability of metastasis Probability of metastasis (in %) =
(GS-5) X (PSA over 3 + 1.5 X T)
GS is the Gleason score and T is the clinical stage estimated by digital rectal examination. T = 0 for stage T1c, 1 for T2a, and 2 for T2b or T2c. Dr. Mack Roach, Chief of Radiation at UCSF, recommends that only men with a risk above 15% should undergo node radiation.
Testosterone Inactivating Pharmaceuticals (TIP)
After IMRT and seeds, TIP is the third leg of the Azure treatment triad. In the most famous study evaluating the benefit of TIP, the mortality rate from cancer after 10 years in the men treated with TIP was reduced to 10 percent compared to 30 percent in the men who did not receive TIP. There are many additional studies that have arrived at the same conclusion. For Basic-Azure, men should receive a combination of IMRT, seed implants and TIP. IMRT should be administered to the prostate and possibly to the pelvic nodes. Men with High-Azure should receive IMRT to the prostate and lymph nodes along with TIP for 18 months. Adding Zytiga also seems prudent considering the results of recently published trials.
ABOUT THE AUTHOR
Mark Scholz, MD is the Executive Director of the Prostate Cancer Research Institute. He is also the Medical Director of Prostate Oncology Specialists Inc. He received his medical degree from Creighton University in Omaha, NE. Dr. Scholz completed his Internal Medicine internship and Medical Oncology fellowship at University of Southern California Medical Center. He is co-author of Invasion of the Prostate Snatchers. He has authored over 20 scientific publications related to the treatment of prostate cancer.