Also known as external beam radiation therapy (EBRT), this treatment option uses high-energy x-rays (or photons) to kill cancer cells. Before treatments start, imaging technologies such as MRIs, CT scans or an x-ray of the pelvis are used to determine the location of the prostate gland. The radiation team may then make ink marks on the skin or insert gold markers near the prostate to use later as a guide to focus the radiation to the right area. Because EBRT cannot be targeted precisely to only the prostate, healthy tissue around the prostate can be damaged. In addition, even if you remain perfectly still during radiation, your organs naturally move, which can lead to inaccurate targeting. As a result, the radiation treatment hits more of the healthy tissue around the prostate, causing common side effects such as bowel and bladder problems, urinary incontinence and sexual dysfunction.
In contrast to conventional radiation therapy, external beam prostate radiation treatment with Calypso real-time tracking continually targets the exact location of your prostate during treatment. Using technology called GPS for the Body® that works with three tiny Beacon® transponders implanted in the prostate during a simple outpatient procedure, the clinician monitors real-time information to precisely and accurately align the prostate with the radiation beam. This not only increases the likelihood of treating the tumor with the full radiation dose, but also reduces the risk of damage to surrounding healthy tissue because the clinician can immediately stop radiation delivery if the prostate moves during treatment. When motion is detected, the patient is repositioned to realign the prostate with the radiation beam, then treatment resumes Side effects have been shown to be less because of the treatment’s precision at targeting the cancer in real time. In a recent clinical study Calypso patients were shown to experience significantly reduced prostate radiation side effects.
Prostate stereotactic body radiation therapy (SBRT) delivers a higher dose of radiation per fraction while lowering the total number of treatments. As compared to typical conventionally fractionated external beam radiotherapy delivered over 40-45 sessions, prostate SBRT is delivered in a 5-fraction protocol, so that the entire treatment course is delivered in less than two weeks. The delivery of these large doses of radiation over a shortened course of treatment creates concern about exposing the surrounding healthy tissue to the same high dose, thus increasing the potential for side effects. Calypso’s real-time tracking technology provides the knowledge that prostate motion is accurately and precisely tracked to allow clinicians to confidently deliver these larger radiation doses. Results of two prostate SBRT clinical studies demonstrated that managing organ motion with the Calypso System enabled clinicians to reduce treatment margins and expose less healthy tissue to radiation, thereby safeguarding patients from the development of radiation-related side effects. (i), (ii) For the right patient, the much shorter delivery schedule combined with the potential for fewer side effects makes SBRT a very appealing option.
(i) Mantz, C.A., Fernandez E., Zucker I., Harrison S. “A Phase II Trial of Real-time Target Tracking SBRT for Low-Risk Prostate Cancer Utilizing the Calypso 4D Localization System: Patient Reported Health-related Quality of Life and Toxicity Outcomes.” 21st Century Oncology, Fort Myers FL. Oral Presentation 121. ASTRO 2010.
ii) Jiang, L et al. “Dosimetric Evaluation of Margin Reduction and Intrafraction Motion for Prostate SBRT” University of Texas Southwestern Medical Center, Department of Radiation Oncology, Dallas, USA Poster 477. Congress of the European Society for Therapeutic Radiology and Oncology (ESTRO), 2011, London, U.K.
A surgical procedure, radical prostatectomy involves removing the entire prostate gland plus some of the tissue around it, including the seminal vesicles. Because prostate cancer may be scattered throughout the prostate gland randomly, the entire prostate must be removed to avoid leaving cancer cells behind. The goal of radical prostatectomy is to contain the cancer cells. Surgery can provide immediate pathology results and allows for an early determination of post-operative PSA status. These are potential indicators of remission and the need for post-operative radiation therapy. The risks with radical prostatectomy are much like those of any major surgery, and long-term surgical complications are often urinary incontinence and sexual dysfunction.
Also called seed implantation or interstitial radiation therapy, brachytherapy involves the use of radioactive sources placed directly into your prostate where they irradiate the cancer from inside the gland. Brachytherapy may be given in addition to external beam radiation, or it may be used as the only form of radiotherapy. In Low Dose Rate (LDR) brachytherapy, small radioactive pellets, or seeds, each about the size of a grain of rice, are permanently left in place. In High Dose Rate (HDR) brachytherapy, a single radioactive source attached to a guide wire travels through multiple small hollow tubes (catheters) placed in the prostate and delivers radiation for a specified amount of time and is then removed. Even though the radiation doesn't travel far, your doctor may advise you to stay away from pregnant women and small children during this time as a safeguard. Brachytherapy can also cause urinary problems and bowel problems as well as sexual dysfunction.
