Radiation Therapy and Prostate Cancer
City of Hope offers many different radiation treatments for prostate cancer and can help provide information on the variety of options.
Radiation therapies offered for prostate cancer
Research is currently underway to determine the best course of action for a man diagnosed with low risk, intermediate risk or high risk prostate cancer.
The longest follow-up and data on prostate cancer comes from both external beam radiation (IMRT on TomoTherapy machine or TrueBeam) and brachytherapy. Here at City of Hope we have both external beam radiation and brachytherapy and are able to give suggestions and recommendations on either treatment taking into account all the patient characteristics.
External beam radiation we can treat either on TomoTherapy or TrueBeam machines. We use image guided radiation treatment daily so that we can minimize toxicity to the bowel, bladder, rectum By having both machines in our department we can compare/contrast the two machines to determine what is best for the patient in terms of giving maximum radiation to the prostate cancer and minimizing radiation to the nearby bladder, bowel, rectum. The picture below illustrates the benefit of tomotherapy in sparing dose to the rectum and bladder (on right) versus 3DCRT (on left).
If we determine that the patient is a good candidate for brachytherapy, we are able to offer this course of treatment as well. We perform all brachytherapy in collaboration with our urologists, and have been performing brachytherapy for over 15 years. With a MRI scan of the prostate, we can better determine who is/is not a good candidate for brachytherapy.
A non radiation option we now have in our department is MRI guided focused ultrasound. Recently FDA-approved to treat metastatic bone cancers, focused ultrasound combines several capabilities that make it promising for cancer treatment. First, the approach uses magnetic resonance to create a more precise image of the cancer so that treatment can be targeted specifically to the diseased area. The method then delivers focused ultrasound waves — heating up and destroying targeted areas of tissue inside the body without a single incision and avoiding healthy tissue. And it measures the temperature and energy accumulation at the treatment site in real-time, so that ultrasound waves can be highly controlled to ensure safety and effectiveness. In addition to providing more targeted, less invasive treatment, this approach will offer new options to patients whose cancer has returned after traditional treatments have failed or who are too weak to withstand surgery or additional rounds of radiation.
Recently, we were the first institution in the U.S. to use focused ultrasound to treat prostate cancer. Unlike other forms of therapy such as surgery or radiation, only the portion of the prostate gland containing biopsy proven cancer is targeted with MRGFUS. Although still under investigation, this approach holds promise to reduce the risk of impotence and incontinence associated with other forms of prostate cancer therapy.
Following prostatectomy, radiation therapy can be given post-operatively if there are certain features seen in the pathology specimen. More commonly radiation therapy is given for patients who show rises in the PSA level during follow-up with the urologists. Patients are treated using IG-IMRT either on the Tomotherapy or TrueBeam machine.
The standard treatment is for approximately 8 weeks, Monday-Friday. Harnessing the imaging platforms in the department, patients typically receive an MRI in addition to traditional CT scanning for treatment planning. In some cases, the MRI may detect disease in the prostate bed that may otherwise have gone unnoticed, allowing the radiation oncologist to potentially give additional dose to these areas.
At City of Hope, we are accruing patients to a ground-breaking clinical trial that is studying the safety and feasibility of using a shorter radiation treatment time to treat patients with rising PSA following prostatectomy. This is known as stereotactic body radiation therapy (SBRT). This technique utilizes IG-IMRT technology to deliver very focused and potent doses of radiation over one and a half weeks, and has been shown to be effective and safe in patients with prostate cancer who received radiation as their initial curative treatment. To assist in localization of the target, metal markers can be placed in the prostate bed under ultrasound guidance in the outpatient clinic. These markers will be detectable on the CT scans and be used to align the patient prior to each treatment delivery (see below image). Patients will also be evaluated for placement of a novel radiotransponder marker known as the Calypso ® system. In addition, a rectal balloon will be inserted for the planning and the daily treatments to ensure the target is stabilized, thereby maximizing the accuracy of treatment (also shown in below image). Interested patients can contact our department for further details regarding this study, and arrange for consultation.
We are also teaming up with basic scientists to determine if a patient even needs radiation and what is the likelihood that they will respond or if they will need a combination of hormones or not through imaging and serum based studies.
Calypso system and prostate cancer
We recently added the Calypso system to our new TrueBeam machine. This involves placement of three beacon transponders (shown on the right) that will be tracked in real time by the Calypso system. Our image guidance in the department already manages interfraction movement of the prostate with respect to the bladder and prostate. With Calypso we can real time track the movement of the prostate and correct for intrafraction movement of the prostate. Calypso recognizes the transponders via radiofrequency waves and can correct motion of as little as 2mm. For the patient, this means even more control with treating the prostate while sparing the nearby normal tissue such as the bladder and rectum.