CyberKnife Steps

Often when I see a man in consultation he is very anxious to start the treatment as soon as possible.  Some hope that they can get the treatment performed within a couple days after the first visit with me.  However, there are multiple steps that need to be accomplished, all in the right order!   The entire technical part of the treatment (steps 6 – 10) can be performed in as little as two weeks, which includes placement of gold markers, mapping, treatment planning, and treatment sessions.   Overall this schedule is much shorter than the one for conventional radiation which takes up to 11 weeks to plan and treat, and much shorter than the recovery time from surgery.

These ten steps will be described in detail in other chapters:

• Consultation with radiation oncologist
• If required: Staging Scans
• If required: Followup appointment to go over scan results and/or to make a final decision
• If required: Hormone therapy for 3 months first to shrink the prostate gland
• Get approval from medical insurance company
• Placement of gold marker seeds and SpaceOAR
• Wait at least 72 hours for the gold markers and SpaceOAR to settle in position
• Mapping with a CT-Simulation and MRI of the prostate gland
• Treatment planning on computer – requires at least 48 hours
• Five CyberKnife treatments, roughly every second day

Typical Treatment Schedule

For patients who are not under time pressure or who live close enough to the center to be able to drive back and forth from home, a typical schedule for the technical options of the treatment will look like this:

• Week 1: Preop visit and placement of gold marker seeds and SpaceOAR
• Week 2: Mapping then treatment planning (half day visit)
• Week 3: CyberKnife treatments
• Week 4: CyberKnife treatments

I treat a lot of patients who live a far distance away from the cancer center, and they want to come to the center and stay for the technical portion of the treatment, and they want it all to be done as fast as possible.  The fastest that I can do this is in 16 days, with the following schedule:

Thursday Day 1	Consents and pre-op visit.
Friday Day 2	Placement of gold marker seeds and SpaceOAR
Monday Day 5	Mapping with a CT-Simulation and MRI of the prostate gland
Thursday Day 8	First CyberKnife
Friday Day 9	Second CyberKnife
Monday Day 12	Third CyberKnife
Wednesday Day 14	Fourth CyberKnife
Friday Day 16	Fifth CyberKnife, and can go home immediately after.

Overview of the Treatment Sessions

CyberKnife treatments are actually quite easy.   All that is required on your part is to be able to lie on your back for 45 minutes.  Stereotactic treatments are typically given every second day approximately, and only on weekdays.  For patients who are only getting 2 treatments in a given work week, I do not mind if the treatments are given on back-to-back days, for example the treatment can start on a Thursday and then also be given on the Friday.

For the CT-simulation and for each treatment we would like your bladder to be “comfortably full”.   We ask that you urinate 30-40 minutes before the treatment and then drink 16oz of liquid.   The purpose of the full bladder is that this will result in having less radiation, on average, hit your bladder.  We also like the rectum to be fairly similar in its fullness for the CT-simulation and for each treatment.   This is trickier to achieve.  For this we may recommend that you have a fleet enema prior to the CT-simulation and prior to every treatment.

A radiation therapist administers the treatment, not the doctor.  During the treatment itself, a therapist will bring you into the treatment room and you will get onto the treatment table.  If you are wearing pants without metal (such as track pants) you can keep them on.  Otherwise your pants are pulled down to you knees, but you will keep your underwear on.  The therapist then leaves the room.  X-ray images are taken of your pelvic area, and the gold marker seeds can be seen.  The treatment computer identifies the marker seeds, and hence knows exactly where the prostate gland is.  The therapist then calls the radiation oncologist who looks at the computer console and verifies that the treatment system has correctly identified the position of the gold marker seeds and the prostate.

Next, the actual treatment is begun.  The treatment machine rotates and then parks in over 100 different positions, one by one.  At each position (which is called a node) a small radiation beam is aimed at the prostate gland for a calculated number of seconds.  Each beam will be on for a different amount of time.  Once the radiation has been delivered from that node, the machine moves onto the next position.  Also during this process the treatment machine will frequently repeat the x-rays to ensure that the gold marker seeds are still in the correct position.  If there has been movement, the treatment machine will make corrections for the movement.

The entire treatment takes about 10 minutes to setup, and about 30 minutes to deliver the radiation.  It is totally painless.  You cannot see or feel the radiation beam.

Once the treatment is finished, you are on your way and there are no limitations.  You can go back to work, or spend the day relaxing as you see fit.

Many patient want to know how we verify the treatment is killing cancer cells.  We can’t.  All we can do is verify that the radiation beams are hitting the prostate gland and that the proper dose is being administered.  The radiation dose and number of treatments is prescribed in advance of the treatment, and we do not modify that dose during the treatment course.  There is no way to verify that the all the cancer cells have died during the treatment course.  But we do know from clinical studies that the dose we prescribe has a high cure rate and is low in symptoms.