About TomoTherapy for Prostate Cancer

 

How does radiation work?

Radiation treatment uses high energy X-rays to change the genetic makeup of cancer cells and take advantage of their rapid growth cycle. By ruining their genetic material, the cancer cells die as they attempt to multiply. The goal of radiation treatment is to eradicate all the cancer cells and avoid or minimize harm to the surrounding healthy tissues. Since cells of normal tissue divide much more slowly compared with cancer cells, they have much more time to recover and divide, and are not as adversely affected by radiation. The majority of normal cells can recover from the effects of radiation and function properly. Each radiation treatment is tailored to each individual patient. Radiation may be used alone, after surgery, or with or without hormonal therapy.

 

WHEN IS RADIATION THERAPY USED?

Radiation therapy is used in about half of patients with prostate cancer. Just about anyone with prostate cancer is a candidate for radiation treatment. It’s generally reserved for patients who are older or with other medical problems. It’s also used sometimes after surgery to prevent or treat tumor recurrence despite surgery.

 

WHAT IS TOMOTHERAPY AND WHY DID WE CHOOSE THIS MODALITY TO TREAT YOUR PROSTATE CANCER?

TomoTherapy is the most advanced concept in radiation therapy. It employs a 360-degree revolutionary treatment system to deliver tens of thousands of radiation beamlets. The beamlets are focused precisely to your unique target area, to kill the prostate cancer cells while minimizing radiation exposure to healthy tissue. It is a form of external radiation which passes through you from the outside. It is also a form of intensity modulated radiation therapy (IMRT), as well as image guided radiation therapy (IGRT), but more precise to the moment (within seconds). Each day prior to treatment, the Tomo unit develops its own CAT scan and we can guide treatment based on what your prostate looks like that minute, not last week or last month. This makes it easier to target only your prostate and minimize radiation to surrounding critical structures, such as the bladder and rectum. Linear accelerators, in contrast, are not able to image the prostate, rectum and bladder directly, the reason we picked the TomoTherapy machine.

 

HOW DOES TOMOTHERAPY COMPARE TO OTHER FORMS OF RADIATION TREATMENT FOR PROSTATE CANCER?

There are several forms of radiation available for prostate cancer, including brachytherapy and external beam therapy. In brachytherapy, radiation is delivered from the inside out using seeds or rods. Seeds type brachytherapy, also referred to as low dose brachytherapy, is acceptable as a single treatment modality only for patients with low risk prostate cancer. It is administered in the operating room under anesthesia, and patients go home the same day. The radioactive seeds are implanted into the prostate using trans-rectal ultrasound guidance in order to ascertain proper placement. The seeds lose their radioactivity over the course of a few months, though it’s safe for the patient and family members even while the seeds are radioactive.
High dose-rate brachytherapy is also administered in the operating room under anesthesia, however in this type of treatment, permanent seeds are not implanted. Rather, temporary rods are placed in the perineum. These rods are hollow and are used to load and unload seeds three times over a 36 hour period while the patient remains in-hospital. This modality is most often recommended to patients with intermediate or high risk disease, and is typically administered in conjunction with some form of external beam radiation treatment, generally completed before the high dose-rate brachytherapy is administered.

External radiation therapy is available in several different types:

Linear Accelerator: this machine delivers high-energy photons or x-rays to treat deep-seated tumors, as in the prostate.  (It also may deliver electrons to treat superficial tumors, unrelated to prostate disease).  The imaging with this modality is not directly coupled to the delivery of radiation, however, prior to treatment of the prostate with this modality, three permanent non-radioactive seeds are inserted into the prostate under local anesthesia.  Each day prior to treatment the linear accelerator images the seeds, an indirect method of targeting the prostate.  Thus, unlike TomoTherapy, the prostate, bladder and rectum cannot be seen directly.

CyberKnife  The Cyberknife System is a computer-controlled, robotic radiation delivery system that attacks tumors with high doses of radiation from many directions or angles with sub-millimeter accuracy. With stereotactic radiosurgery there is no incision, cutting or anesthesia. Radiosurgery does not remove the tumor or lesions, but instead, uses the high doses of focused radiation to destroy tumor cells and stop the growth of cancer cells. At the core of the Cyberknife System is technology that continuously and automatically tracks the tumor's and patient's position - including his or her respiratory motion. It uses this information to guide and position the radiation beams to target the tumor, while carefully sparing the surrounding healthy tissue.  Treatment of prostate cancer with the Cyberknife has not been compared to other forms of radiation and we do not, therefore, consider it to be a standard of care for prostate cancer.

Three-dimensional conformal radiation therapy: this method of external beam radiation includes delivery of ionizing radiation from several different directions, all converging onto the central target (prostate).  In this way, the cumulative dose of radiation to the prostate is high, whereas the radiation dose to the surrounding non-cancerous tissues is low.  This method is similar in principle to Tomo therapy, but with only several portals 3DCT is less conformal, and it lacks the immediacy of image guided techniques available in Tomo.  In other words, 3DCT is less precise than Tomo.

Proton Beam: Protons are a form of radiation with a charged particle which theoretically can be better aimed than an x-ray, and have been shown to be advantageous in the treatment of  certain pediatric brain or spinal cord tumors.  However, no studies to date have shown any such advantage over IMRT or TomoTherapy in the treatment of prostate cancer.

 

What is the treatment process?

The process begins with consultation, first with your urologist, and then with one of our radiation oncologists.  If all are in agreement, you will be scheduled for a Simulation session.  You’ll be asked to lie still on a CAT scan table by the radiation therapist as cross-sectional images of your anatomy are obtained.  They’ll use these to learn the exact location of your prostate relative to the surrounding structures.  To help you remain still during treatment and to ensure that the radiation beam is aimed correctly, “immobilization devices” will be custom-made for you.  You will be marked with speck-sized tattoo dots to assist in the daily focalization of your anatomy.

Next, the dosimetrist, radiation physicist and radiation oncologist use a treatment planning computer system to determine the radiation dose, delivery time and treatment technique.  The radiation oncologist uses all the relevant information to decide how much radiation is needed, how it will be given, and how many treatments you need.

In general, treatment is delivered once a day, 5 days a week, for  8 ½ to 9 weeks.
The actual radiation therapy treatments are completely painless. While the treatment appointments may last about an hour, the actual time of each treatment is only a few minutes.  The rest of the time is used to set up the equipment and place you in the correct position.  Your job is easy.  You just lie still and relax on a treatment table positioned in the radiation machine.

After you are in position, the radiation therapist leaves the room and turns on the machine.  You can still communicate via the closed circuit television and intercom.  You will feel nothing unusual.  The CAT scan performed prior to the treatment will take 2-3 minutes, after which the treatment will be delivered over the same time period.

 

Safety measures:

The New York Times published two lengthy articles on radiation in February, 2010.  The first covered two very unfortunate misadministrations that occurred in New York, using conventional linear accelerators.  The second touched on additional mistreatments in the U.S. and questioned the “vulnerability of patient safeguards” as new technology is developed to fight cancer.

At the Garden State Prostate Cancer Center, providing safe and high quality radiation therapy is our highest priority.  We take pride in our commitment to quality.  We go beyond what is required to ensure patient safety and treatment accuracy.

The Garden State Prostate Cancer Center uses TomoTherapy for the treatment of prostate cancer rather than the conventional radiation therapy that was highlighted in the news articles.  TomoTherapy radiation treatments are performed using the system’s integrated daily pre-treatment CT imaging capabilities.  This is the only treatment machine that non-invasively images the prostate, bladder and rectum immediately prior to each treatment to guarantee proper targeting of the treatment volume.  The Radiation Therapists make day to day adjustments based on bladder and rectum changes.  This ensures the accuracy of the treatment target each day.

We only treat prostate cancer, making our staff and the Center highly specialized and proficient in the treatment of this disease.  Our clinicians are all Board Certified and State licensed.  Our Physicists, Medical Dosimetrist, Radiation Therapists, and Registered Nurses are also all board-certified and / or State licensed.  The Prostate Cancer Center at Garden State Urology has had, since its inception, multiple safeguards in place to ensure patient safety when undergoing treatments.  They are:

1. Daily and monthly Quality Assurance testing on the TomoTherapy machine to assure dose accuracy and the proper functioning of the mechanics of the machine.
2. After the initial Planning or CT-Simulation (CT-Sim), the Radiation Oncologist meets with the Medical Physicists and defines or draws a treatment volume for that patient.  The following day, a second radiaton oncologist looks at that treatment volume and double checks it.  If they both agree with the treatment volume, the work begins to create a treatment plan for that patient.  Any disagreements are reconciled prior to creating a treatment plan.
3. Prior to the first radiation treatment our Physicists conduct quality assurance testing using a phantom.  A phantom simulates a patient and measures the radiation dose and distribution of that dose.  The quality assurance testing will confirm that the dose and distribution is correct for that individual patient.
4. Before a patient’s first treatment, the Chief Therapist reviews the patient’s full chart for all proper documentation, and does a final review of the treatment plan.
5. On the day of treatment, the Radiation Therapists also review the chart and treatment plan.  When the patient is ready for treatment, the following safety measures are employed:
• The patient is properly identified, including a photograph ID
• At least 2 Radiation Therapists are involved in treatment at all times
6. The daily scan and registration [of the treatment target] are reviewed on-site by one of the Radiation Oncologists

 

Garden State Urology is accredited by the American College of Radiation Oncology:

As part of its mission, ACRO developed a practice Accreditation Program in 1995, consisting of practice standards for radiation oncology. Accreditation is a voluntary process in which professional peers identify standards indicative of a quality practice, and an audit is conducted to assure that these standards are followed. Since its establishment, the accreditation program has undergone periodic revisions to reflect clinical and scientific advances within the field, providing for the safe and effective practice of radiation therapy.