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Total Quality History Implant Procedure
Clinical Course Implant Treatments Candidates
Introduction to Total Quality
The University of Michigan’s Radiation Oncology Department in Ann Arbor, Michigan and its affiliate hospital, Providence Hospital, have an active clinical research program in permanent radioactive seed implants for prostate cancer. This research program is based at Providence Hospital , a full affiliate of the University of Michigan (Radiation Oncology physicians at Providence are full time Faculty at the University of Michigan). Implant techniques are continually being refined and have steadily improved over the last decade. Their success rates have steadily risen with these improvements. Much of the research on prostate implants at the University of Michigan/Providence has been dedicated to improvement in implant quality. Improvements in quality impact implant procedures in the following ways:
1. How suitable candidates are selected for implants.
- Not all men with prostate cancer are suitable candidates.
- There are many excellent options for prostate cancer treatment.
2. How an implant procedure is planned.
- What measures are taken to assure full dose while avoiding side effects or complications?
3. How an implant procedures is performed.
- Is the procedure done in one step?
- Is seed placement checked during the procedure?
4. How the implants are checked after the procedure. (post implant quality check)
- What is considered a "good" implant?
- What is the best way to check an implant?
5. How men are monitored and supported following the procedure.
- What effects do implants have on quality of life?
Total Quality refers to systematic improvement of all the critical areas of concern. Quality improvement in one area will influence the quality of other areas. In the figure below Technical Quality refers to how the procedure is planned and carried out. Post Implant Quality refers to how the implant is checked after the procedure. Quality of Life refers to efforts to measure the impact of implants on quality of life.
This module discusses prostate implants. Other excellent options are available for the treatment of prostate cancer, and the decision of what is considered the "best treatment for you" remains a personal choice. By honestly presenting the advantages and disadvantages of implant treatment for prostate cancer, men are better prepared to make an informed decision about their treatment.
History
In permanent prostate implants, small radioactive pellets, smaller than a grain of rice, are placed within the prostate gland.
Radiation treatment is therefore administered from inside the gland rather than by an X-ray beam (external beam radiation) from outside the body. These radioactive pellets, or seeds, provide a continuous dose of radiation over a period of weeks or months. The continuous radiation dose contrasts significantly with the dose delivered by external beam radiation therapy where once a day for a brief period of time (5 minutes) the radiation dose is administered.
One major advantage of permanent prostate implants is that a very high radiation dose can be administered to the prostate with very limited exposure to the normal tissues around the prostate. The disadvantage is that if some of the seeds are not in proper position, an area of the prostate may not receive a sufficient dose, or a critical organ nearby may receive an excessive dose. The good news is that using today's highly sophisticated imaging equipment, accurate implant position can be confirmed, ensuring correct dosage to the entire prostate and limited dose to adjoining organs and tissues.
Two different radioactive seeds have been used in prostate cancer treatment. One is 125I (radioactive iodine). This seed gives radiation over a period of many months with 7-9 months being the "active life" or lifespan of the treatment. After this period of time, the radiation dose is minimal and of no consequence. The other seed employed is 103Pd (palladium). This delivers its dose very rapidly and after 2 to 2-1/2 months almost all of the radiation has been delivered. Both of these types of radioactive seeds have proven effective in treating prostate cancer. There are a variety of arguments for one versus the other, but it appears that whenever they have been directly compared, the results are quite comparable. This includes the number and degree of side effects and complications, as well as the effectiveness of therapy. Again, it is the quality of the placements of the implants and not the radioactive source that defines the outcome.
Prostate implant therapy began in the 1960s, and there are four distinct eras in the history of the procedure. In each era a different concern surfaced and was addressed.
Four Eras of Implant Treatment
Memorial Sloan-Kettering Era
In the 1960s and 1970s, the use of radioactive seeds for treating prostate cancer was pioneered at Memorial Sloan-Kettering in New York. During that period, a major operation was required to insert the seeds properly. An incision was made into the abdomen and needles were passed down into the pelvis to place the seeds within the prostate. This was essentially a "blind" procedure where the surgeon placed the needles by touch. Although the initial response was promising, often the seeds were not well placed and parts of the prostate did not receive a sufficient dose to cure the cancer. This surgical technique was abandoned due to poor long-term results.
Ultrasound Era (Seattle)
In the 1980s, ultrasound technology improved the ability of the physician to visualize the prostate. This also allowed direct visualization of the needles passing into the prostate to deposit the seeds. No incision was required since the needles were passed through the skin below the prostate. The pioneering work was done in Seattle through Drs. Blasko, Grimm, and Ragde. Excellent initial results as evidenced by declines in Prostate-Specific Antigen (PSA) levels and cure rates comparable to other treatments were achieved. During this period it was believed that most of the implants were excellent by virtue of this improved visualization and a drop in PSA level after implant. In time, careful analysis of the implants by post-implant checking revealed that some flaws remained in the technique. This led to the next era, the so-called Post-Implant Era.
Post-Implant Era
In the early 1990s, attention shifted towards checking the seeds after surgery to verify that they were in proper position and that the prostate received a full dose of radiation. Many studies, including many studies completed at the University of Michigan /Providence confirmed that despite direct visualization by ultrasound, it was still possible for seeds to be deposited out of ideal position. Underdose was still possible and in the next five years, dramatic advances in technique occurred. Standards of judging a quality implant were developed and are currently widely applied. The proof of a quality implant program was no longer the number of implants done, but the number that could be confirmed as excellent by post-implant dosimetry, a method of measuring the dose of radiation actually delivered to the prostate and adjacent normal tissues. Many institutions reported dramatic improvements in cure rates as implant quality improved (see Why Quality Matters). As full-dose implants were accomplished on a regular basis, attention turned to toxicity and the side effects associated with the implants. Full-dose implants revealed the peril of implant therapy—the fact that significant toxicity was possible due to dose to adjoining tissues and nearby organs. This led to the Quality of Life Era.
Quality of Life Era
In the late 1990s, a large volume of knowledge accumulated regarding quality of life changes after implant procedures. Significant bladder and rectal distress occurred in a number of men. Rules were developed for selecting implant candidates based on their pretreatment prostate size and bladder function. With a greater understanding of the mechanism of bladder, bowel, and sexual potency changes, treatment techniques evolved again to address these issues.
These changes led to improvement in the side effect and complication rates. In the Quality of Life era, it is possible to achieve excellent dosage coverage of the prostate while decreasing severe side effects and complications. Nonetheless, some men do experience considerable side effects with implants. For men treated today, these symptoms are usually in the nuisance range. Implant treatment should not be considered an "easy" form of radiation therapy. Any effective treatment for prostate cancer carries a risk of side effects and complications.
The Implant Procedure
The prostate gland is located directly under the skin between the anus and the scrotum. During the implant procedure, using ultrasound technology, the needles that pass through the skin into the prostate can be visualized by the surgeon and radiation oncologist on the ultrasound screen. Placement of the seeds can also be verified with the ultrasound as both the needles and the seeds can be clearly seen. There are wide variations in how this procedure is performed, but there are five essential steps.
First, a picture of the prostate is obtained by Ultrasound or Magnetic Resonance Imagery (MRI).
Second, the picture is inserted into a software program that generates a customized plan that indicates exactly where the seeds must be placed within the prostate. A large prostate will require many seeds and a smaller prostate will require fewer seeds. A variety of techniques have evolved to place the seeds. Some groups place the seeds on the perimeter of the prostate; others place them throughout the prostate. Regardless of the technique, a customized plan is generated for each individual.
Third, needles are passed through the skin between the anus and the scrotum and into the prostate. The needle positions are checked by ultrasound or by MRI. Regardless of the device used to image the prostate, all techniques involve seeing the prostate and checking the position of the needles before placing the seeds.
Fourth is the monitoring of seed drop-off during the procedure. Although the needles may be in perfect position the seeds may migrate slightly when they are released. For most surgeons practicing modern implant techniques, there is an attempt to check where the seeds are placed. This can be done while the individual is still in the operating room using X-ray or ultrasound technology. Corrections are made if the seeds are far from the planned position.
Fifth is post-plan evaluation. The success rate of implants is directly related to the quality of the implants, or whether the seeds are in the proper position and the prostate receives a full dose of radiation. This may be the most critical step. The prostate and the seeds must be pictured and the dose must be calculated to ensure that the entire prostate is receiving a full dose. If there are areas of the prostate without seeds, a lower dose will result and this may result in therapy failure. Although post-implant checking is not uniformly applied, it is currently recommended as a critical step by the American Brachytherapy Society, a national organization of physicians who perform implant radiation in a variety of cancers.
Two different radioactive seeds have been used in prostate cancer treatment. One is 125I (radioactive iodine). This seed gives radiation over a period of many months with 7-9 months being the "active life" or lifespan of the treatment. After this period of time, the radiation dose is minimal and of no consequence. The other seed employed is 103Pd (palladium). This delivers its dose very rapidly and after 2 to 2-1/2 months almost all of the radiation has been delivered. Both of these types of radioactive seeds have proven effective in treating prostate cancer. There are a variety of arguments for one versus the other, but it appears that whenever they have been directly compared, the results are quite comparable. This includes the number and degree of side effects and complications, as well as the effectiveness of therapy. Again, it is the quality of the placements of the implants and not the radioactive source that defines the outcome.
The Clinical Course
After implantation, radiation continues to be delivered to the prostate by the seeds. Over time, the radiation dose builds up enough in the region of the prostate to cause some irritation with urination and sometimes some rectal frequency and urgency. These side effects are usually in the nuisance range and are manageable with minor medications. However, for a small percentage of men, these symptoms can persist and become quite bothersome. These post-implant symptoms are related to planning strategy (where seeds are placed within the prostate) and the patient’s baseline pretreatment symptoms. As knowledge has increased in the Quality of Life Era, severe side effects and complications are far less likely. With time, symptoms resolve for the majority of men, but some men will continue to require medication to address side effects for several months.
Types of Implant Treatments
Permanent prostate implants are used in two ways. The first is for men who have disease limited to the prostate or who have very little risk of disease beyond the prostate. These men may be treated with implants alone. In this type of treatment, a very high dose of radiation is applied to the prostate through the seeds and no other therapy is administered. The second is for men who may have diseasebeyond the prostate. In these men, external beam radiation therapy is combined with implant therapy—so-called combination therapy, or combined modality therapy.
There are two ways to provide combination therapy. One way is to give five weeks of external beam radiation before the radioactive seeds are implanted. The other is to place the implants first, followed by external beam therapy. Regardless of the method used to combine external beam and implant therapy, the advantage is that a slightly wider margin of dose is administered in case there are cancer cells beyond the prostate.
There is a great deal of controversy about who requires implant therapy alone and who requires combination therapy. One school of thought is that implants alone are as effective as implant therapy plus external beam therapy, even in men who would be expected to have disease outside the prostate. For many of these men, even if the disease extends beyond the prostate, it appears that implant therapy provides adequate coverage to provide cure. On the other hand, other groups believe that external beam therapy plus implant therapy is required for all men. In a center advocating this approach, no man would be treated solely with implant therapy or external beam therapy. At the University of Michigan and Providence Hospital each man is evaluated on an individual basis to determine the most suitable approach.
Defining Candidates
Men diagnosed with prostate cancer may consider implant therapy if there is no evidence of disease spread beyond the prostate and pelvic area. If the disease has spread to bone, liver, or lung, intensive local treatment options such as implant therapy are not appropriate. Individuals should not select implant therapy because it appears to be easier or more convenient. The main reason to consider implant therapy as a treatment option is that a greater dose of radiation is applied than in any other treatment option, including intensity modulated external beam therapy. The greater dose may improve the cure-rate, but it may improve the cure-rate at a cost of greater side effects. In a recent series, as techniques have dramatically improved, very high doses can be administered with acceptable side effects. The recent cure-rates reported with high-quality implants are extremely high for all degrees of prostate cancer, and each person must decide whether the possible increase in side effects is acceptable.
There are important non-cancer issues to consider before someone is thought of as an implant candidate. First, the individual should not have many urinary symptoms before treatment. Implants are likely to increase these symptoms temporarily. Second, the individual should not have an extremely large prostate. A large prostate may require hormone therapy to decrease its size. Third, prior prostate surgery can make implantation difficult, making other treatment approaches preferable. Finally, a candidate must be adequately fit to undergo a spinal or general anesthetic.
The decision on which type of therapy to use depends on the extent of the disease. For example, is it likely that all the cancer is within the prostate gland? Or is there a chance that it has spread outside the gland or to nearby organs? When men are seen for evaluation, three main critical factors are known. The three factors are Gleason Score (grade), stage, and PSA level. These factors are combined to predict the location and extent of the disease. The examining doctor determines the clinical stage. The Gleason Score is obtained from the biopsy. The PSA level is determined using a blood test. A computer program has been generated that will calculate the extent of an individual's prostate cancer. The three factors can be inserted into the program. This program uses a Partin Table to predict the location of the cancer.
There are many other ways these three factors can be combined to determine the likely extent of disease. Two methods to combine these factors are used in this web site – the Partin method, and the Risk method. These are discussed in detail in the Prostate Cancer Evaluation section. Using the program you may insert your Gleason Score, Stage, and PSA and calculate the extent of disease by both methods.
