Cancer of the prostate that is localized can be treated with watchful waiting, radical prostatectomy, cryosurgery and radiation.
At this time, the “best" treatment for localized prostate cancer has not been determined. The patient’s age and life expectancy, medical history, Gleason score factor into the treatment recommendations.
Guidelines have been established by the 2007 National Comprehensive Cancer Network (http:www.cnnc.org). They can be summarized in the following table based on life expectancy and the cancer risk:
Life expectancy Prostate cancer risk Treatment Options
Less than 5 years Low Risk Prostate Cancer • Watchful Waiting
• Radiation Therapy
More than 5 years Low Risk Prostate Cancer • Radical Prostatectomy
• Radiation Therapy
More than 5 years Intermediate Risk Prostate Cancer • Radical Prostatectomy
• Radiation Therapy
More than 5 years High Risk Prostate Cancer • Radiation Therapy with Adjuvant Hormonal Deprivation Therapy
The definition of low, intermediate and high risk cancer established by the 2007 National Comprehensive Cancer Network: (http:www.cnnc.org)
Low Risk Prostate Cancer • Stage T1 or T2
• Gleason Score of 6 or less
• Serum PSA of 10 ng/ml or less
Intermediate Risk Prostate Cancer • Stage T2b or T2c
• Gleason Score of 7
• Serum PSA of 10 to 20 ng/ml
High Risk Prostate Cancer • Stage T3a or T3b
• Gleason Score of 8 to 10
• PSA greater than 20 ng/ml
The prostate has a “margin” which is a thin membrane (capsule of the prostate). Just outside the capsule are the small nerves which look like a network of spider webs that go to the penis. A pathologist examines the capsule after surgery to make sure the cancer is confined to the prostate. If the prostate can be removed with a clear margin before a metastasis, the patient has an excellent chance of cure. A patient with High Risk prostate cancer (Gleason 8 - 10) has a high chance of cancer in the capsule. Capsule invasion by cancer increases the chance of a recurrence of the cancer after surgery. Radiation can be used after surgery, but the radiation dose must be kept low to avoid complications. This limited dose has a lower cure rate. Surgery is not appropriate for patients with significant medical issues since they may have higher complications with the heart and lungs. Intermediate risk cancer has a higher incidence of a positive margin than the low risk cancers. A patient with an intermediate risk cancer has a higher chance of capsule invasion than a patient with low risk cancer. He may feel the risk of a positive margin is too high and therefore may elect radiation.
Our data has been published multiple times and the most recent update in 2010 reviewed 3200 patients treated from 1997 to 2007. It provided one of the largest non-actuarial series (does not use mathematical projections of data – just the real data). Our patients were treated with Iodine monotherapy or partial dose Palladium followed by a partial dose of IMRT/IGRT. The 10 year PSA relapse-free survival was 94% for the patients with low risk prostate cancer who were treated with Iodine monotherapy. It was 96% for men with low and intermediate risk prostate cancer who were treated with Palladium seed implant followed by the IMRT/IGRT. A The 10 year PSA relapse-free survival was 92% for men with high risk prostate cancer treated with the combination of Palladium seed implant followed by IMRT/IGRT. Some, but not all of these patients, received adjuvant hormonal deprivation therapy ranging from 4 to 18 months.
A PSA relapse-free status is the best assessment of treatment success.
The 15 year data is being collected and is very similar to the 10 year data. Many patients are lost to follow-up because they either move away or perhaps die from other medical conditions. Many patients who are PSA relapse-free do not come back to their Urologist or Radiation Oncologist and are followed by their primary care doctor.
Toxicities were minimal and similar for both the iodine monotherapy and the combination palladium + IMRT/IGRT therapy. The high PSA relapse-free survival rate was due to the high dose of the radiation to the prostate, although it was delivered at a low rate over a longer time. The target radiation dose with Iodine monotherapy (treatment only with Iodine seeds) was 176 Gy. The target radiation dose with the Palladium seed implant followed by IMRT/IGRT (combination therapy) was 103 Gy. However, the combination therapy dose increased in the tissue between the margin of the prostate and urethra to nearly 220 Gy then dropped to 78 Gy at the urethra and margin of the prostate near the rectum and bladder. In contrast, the highest dose IMRT alone or Proton beam therapy can deliver is 78 - 81 Gy. This drop in radiation is known as the Dosimetry gradient. The side effects from the brachytherapy are generally lower than IMRT alone or Proton Beam because the dose more rapidly decreases from the edge of the prostate to the bladder and rectum.
Radiation therapy results are dose dependent (e.g. dependent on the dose given to the prostate) and the treatment with the highest prostate dose has the best cure rate. Likewise, side effects are dose dependent (e.g. dependent on the dose to the rectum and bladder) and the treatment that has the least bladder and rectal exposure will have the least side effects. Regardless of the form of radiation delivered, the dose to the bladder and rectum dose cannot exceed a critical dose of about 81 Gy. All radiation treatments except brachytherapy are limited to this prostate dose to avoid side effects. This lower dose has a 10 year PSA relapse-free survival of 85% (depends on the prostate cancer risk). The higher prostate dose can only be achieved by the limited area of radiation emitted from individual seeds. Each tiny seed radiation creates a low dose radiation field that overlaps the field from the neighboring seed like overlapping circles. The computer calculates the prostate dose from all these circular areas to achieve a high prostate dose and low urethra, bladder and rectal dose. Our Iodine seed implant monotherapy or Palladium seed implant combined with the conforming IMRT/IGRT has the best published 10 year PSA cure rate of any radiation therapy.
INSERT PICTURE OF PROSTATE WITH THE SEEDS AND THE TRANSRECTAL ULTRASOUND.
INSERT PICTURE OF THE DOSIMETRY CURVES.
Question: How is a patient evaluated after radiation therapy?
Answer: PSA and Digital rectal exam are the mainstay of evaluation. Typically, we follow patients every 3 – 4 months for 2 years, then every 6 months until year 5. After year 5, it is annually. Bone scan, CT, MRI and the new F-18/PET/CT-Bone scan are ordered if there is a PSA rise.
Question: How low does the PSA fall after radiation?
Answer: There is no absolute threshold for the PSA nadir (lowest value), but our center uses 1.0 ng/ml as a goal for successful treatment. There is tremendous variation in the time it takes to reach a nadir after radiation. Some patients reach a nadir after a few months while others can take a few years. There is no absolute PSA nadir value that is accepted for success or failure or treatment. Many patients reach a PSA of <0.1 ng/ml and most are below 0.5 ng/ml.
Question: What is a PSA flare?
Answer: The PSA can take a “bump” or “Bounce” 18 to 24 months after radiation. The levels can go up to 20 ng/ml. The evaluation reveals no recurrence. These “bumps” in the PSA occur in nearly 30% of patients. The cause of the flare or bump is not known. In most bumps, the PSA rise is temporary and then falls in a quick fashion – up and down over a 6 – 9 month period. A PSA bounce can be confused with a PSA failure.
Question: How predicative is PSA of prostate cancer recurrence?
Answer: Prostate cancer patients who have a lower prostate specific antigen (PSA) nadir (the lowest PSA value) after radiation therapy are less likely to have the cancer return than patients with a higher PSA nadir. The longer the PSA continues to fall and the lower its ultimate lowest value (nadir) the better the patient's chances of disease-free survival. In our patients, those that had ultimately had PSA at or below 0.5 ng/ml did not have a recurrence. Those that achieved a 1.0 ng/ml at 1 year did not have a recurrence.
Question: How long does it take for the PSA to nadir?
Answer: PSA levels may not decrease to a zero after radiation and may take 2 to 3 years to reach the posttreatment nadir (lowest PSA value).
Question: What is the definition of a PSA failure after radiation therapy?
Answer: Three consecutive increases in the PSA after radiation.
Question: What is the pattern of PSA in a recurrence of prostate cancer after radiation?
Answer: This varies, but is usually a slow steady and progressive increase.
Question: What can be done if the cancer comes back after radiation?
Answer: Many options are available including cryosurgery and removal of the prostate. Most of the recurrences are not in the prostate but distant metastases that were likely present before the radiation was started.
Question: If I have intermediate risk disease how can I decide between surgery and radiation?
Answer: There are predictive tables including the Partin table developed at John's Hopkins that can help a patient decide. These tables shows the risk of a positive margin using the stage and Gleason score. http://urology.jhu.edu/prostate/partintables.php