The following pages are devoted to treatment options that are available at other centers, as viewed from our perspective on the published medical data – the reported results from the leading centers of excellence representing each of the specialties involved in treating prostate cancer.
Proton-beam vs Intensity-Modulated Radiation Therapy: Which is best for treating Prostate Cancer? –
The June 2008 issue of Oncology Journal (volume 33, number 7, pages 748-753) presents the most current assessment of the heated battle between protons and photons. The article is authored by radiation oncologists at Harvard Medical School, the first institution in the world to utilize proton therapy (primarily for small brain tumors). Many of the image-guided techniques (especially DART) cannot be accomplished with protons.
Robot-assisted radical prostatectomy (RARP) and laparoscopic (LRP) surgery for prostate cancer have been widely advertised as highly preferable, minimally invasive alternatives to the conventional radical prostatectomy (RP) performed under a surgeon’s hands. After all, who wouldn’t want “DaVinci” performing his surgery? Laparoscopic and robotic radical prostatectomy do offer certain advantages over conventional radical prostatectomy, including less blood loss and pain, shorter hospital stays, and faster recovery times, although the robotic procedure takes longer to perform (the risks of which are discussed below). Although the laparoscopic and robotic prostatectomy is a technically challenging procedure, according to its proponents, in experienced hands, RARP and LRP may be considered comparable to the open radical procedure.
What is the Cyberknife® Robotic Radiosurgery System?
The Cyberknife® is essentially a linear acclerator mounted on a robotic arm. This modality was developed at Stanford in the 1990’s, and the technology is manufactured by Accuray, Inc of Sunnyvale, California. While FDA-approved, the Cyberknife® protocol is now being combined with Varian Medical Systems’ IMRT technology. We have reservations about the Cyberknife® based on its very penetrating radiation dose. The bottom line is that whenever you hypofractionate radiation (fewer treatments over a shorter time frame using higher radiation doses per treatment), you are making a compromise for the long haul. That is, expect significant increased side effects over time. With prostate treatment, we’re talking about progressive damage to the bladder, urethra, rectum, neurovascular bundles, etc. over time. These symptoms will most likely begin to manifest between and beyond 12 months after treatment. We would never consider utilizing this type of modality at our center unless a patient’s life expectancy is 6 months or less.
What is the Calyspo® 4D System and how does it compare to DART?
The Calypso® 4D Localization System is an attempt to address the problem of organ motion in external radiation therapy. According to the manufacturer. “Calypso Medical has developed a platform to objectively locate the tumor and monitoring tumor motion accurately and continuously without adding ionizing radiation. The Calypso® 4D Localization System consists of three components: the Calypso® 4D Localization System located in the treatment room; the Calypso® 4d Tracking Station located in the control room and Beacon® transponders interact with the Calypso System and locate the tumor’s position, guide the therapist to setup the treatment…”
In comparing the Calypso® 4D System DART, it is important to keep in mind that our Varian DART system is an integrated system that is a fully interfaced piece of equipment that delivers precise dosing of radiation to intraprostatic sites as well as periprostatic margin and affected lymph nodes. DART accomplished all of this in addition to accounting for organ motion in real time during the actual treatment, as well as real time dose optimization to intensify dose to specific targeted areas. It adjusts for dose to identified areas spontaneously while de-modulating or lessening the dose to surrounding critical structures.
Calypso, on the other hand, is essentially a piece of equipment that can be adapted to any linear accelerator. The Calypso system functions much like a gold seed marker in the prostate. Little electromagnetic transponders (called beacons) are placed into the prostate (2-3 of them) and they serve as a localization technique to track where the prostate is. It is then up to the radiation therapists delivering the treatment to identify if the target is not being treated appropriately and the patient needs to be moved. This is not near the sophistication of an integrated system like DART, and can only account for prostate mobility. It cannot account for movement and identification of surrounding critical structures such as bladder and rectum, not to mention penile vessel anatomy, penile bulb, etc. Nor does Calypso offer respiratory gating, which is crucial for tracking organ motion and a key to achieving dynamic adaptive radiotherapy.
“Truebeam” for Prostate cancer?
“Truebeam” with Calypso – While marketing messages tout the combination of Varian’s “TrueBeam” with Calypso as a boon to patients, the extremely fast treatment with unproven high doses of radiation has many in the field concerned about the risk of long-term damage to tissues including, but not limited to, serious rectal, bladder and urethral damage as well as soft tissue necrosis (breakdown of tissue sloughing) and osteoradionecrosis (breakdown of the boney matrix which leads to uncontrolled infections – osteomyelitis). Similar concerns exist regarding the”Cyberknife” which similarly uses completely unproven high radiation doses per session. Meanwhile, the “TrueBeam” with Calypso only tracks prostate motion, which is simply not enough. We are concerned about prostate tracking as well, but also about the location of tumors within the prostate and how they may deform in shape as the prostate moves—not to mention the motion of other critical organs such as the rectum, bladder, urethra, neurovascular bundles and other regions which have a very important impact on post-treatment sexual function including the penile bulb and penile tissues such as the proximal crux (beginning of the penile shaft).
CyberKnife, introduced 5-6 years ago, attempted to reduce the weeks-long traditional radiation treatment protocol by directing higher levels of radiation to the gland during fewer treatments (typically 5). These quicker, higher dose treatments have historically brought with it an increased risk of urethral and rectal fistulas, bladder damage, ulcerations and bone necrosis resulting from collateral radiation
exposure. The real benefit of quicker treatment was the “through-put” advantage for the treatment center – increasing the number of patients treated by a diminished number of staff. It’s all about cost cutting!
TrueBeam” attempts to maximize this benefit to the treatment center owners, proposing that a typical 45 minute to an hour CyberKnife treatment can now be completed in less than 1 minute. This need-for-speed begs the question of accuracy and attendant issues resulting from organ movement during treatment.
Understand that this approach is experimental and has no published research results to back up the manufacturer’s claims.
At Dattoli Cancer Center, it has long been our philosophy that small, accurate doses of radiation over time produce the best results with the fewest documented side effects. These carefully designed and modulated treatments last 5-15 minutes and are administered daily over a 6 week period. This is how we produced the longest published cure rates with the fewest side effects. As Dr Dattoli has said, “If these modalities were time tested and superior to the most advanced Dynamic Adaptive Radiation (DART) as used at our Center, we would be using them”.
Your cancer didn’t grow overnight; you can’t expect to destroy it that quickly either.