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Patients who pursue temporary brachytherapy as their prostate cancer treatment will undergo a planning stage. A radiation oncologist, a urologist, and a physics team will carefully plan the minimally invasive surgery to ensure the seed is put in the correct location. The radiation oncologist and the physics team design a map for the flexible plastic catheters. The oncologist uses the transrectal ultraound (TRUS) to take pictures of the prostate and surrounding organs every five millimeters. After imaging, which takes about 15 minutes, the oncologist writes a prescription for the amount of radiation needed, then gives the prescription and images to the physics team. The physics team arranges a pattern for the small and flexible catheters that will be inserted into the prostate gland.
During the minimally invasive surgery, only one iridium-194 seed is used. The seed is inserted through the catheters one at a time. Because they are flexible plastic instead of rigid steel, the catheters can be guided to wherever the medical team plans for them to go. A urologist can maneuver around an enlarged prostate gland or an interfering pubic arch. Patients therefore do not need to undergo neoadjuvant hormone therapy.
Before the procedure, patients usually start antibiotics to help prevent an infection and undergo mechanical bowel preparation. Not eating anything after midnight or taking enemas or laxatives are all examples of bowel preparation. Fecal matter could interfere with the treatment. Before beginning, an anesthesiologist puts a patient under general or spinal anesthesia that numbs him from the waist down. Patients who remain awake should not laugh, cough, or talk because these activities could upset the precision of the treatment.
Minimally Invasive Surgery for Prostate Cancer
A hospital stay for temporary brachytherapy lasts 24 to 36 hours because a patient receives two or three treatments. He is placed in the lithotomy position, meaning his feet are put into stirrups and his legs are lifted to 90 degrees. This position gives the doctor a clear view of the perineum, which is cleaned and then possibly shaved according to the practice of the center. The doctor inserts an ultrasound probe into the rectum and attaches it to a stabilizing device which holds the tool for the duration of the treatment.
Some doctors will hold the perineal template in their non-dominant hand while they are inserting the catheters. The doctor uses the perineal template to guide the percutaneous insertion of 20 to 49 catheters. The number of catheters depends largely on the size of the prostate gland. The free-hand technique, in addition to the malleability of the catheters, allows the doctor to maneuver around the pubic arch and place the catheters according to the plan. The doctor then fixes the perineal template to the stabilizing device.
A computer inserts a single iridium-194 seed into a catheter and leaves the seed there for 5 to 15 minutes. The computer repeats this process with each of the catheters. After finishing, the catheters are left in place and the patient is transported to a hospital room. He will undergo 1 or 2 more sessions before his prostate cancer treatment is complete. The entire procedure takes a day or two. In between treatments, patients rest in a hospital bed. They may roll from side to side, but they cannot sit up without breaking a catheter.
Temporary brachytherapy leaves no radioactive seeds inside the body, therefore, there is no risk for seed migration. Some researchers are also finding that high dose rate brachytherapy has a lower incidence of cold and hot spots. A cold spot occurs when an area is not adequately irradiated, while a hot spot occurs when an area is over-irradiated. Cold spots may lead to prostate cancer recurrence while hot spots may lead to damage of the rectum or bladder.
Post-operative Seed Implants
Most patients move around freely as soon as the catheters are removed and the anesthesia wears off. Doctors will prescribe antibiotics and possibly an alpha-blocker, which relaxes the neck of the bladder and decreases the severity of urinary side effects. Patients may also take over-the-counter medications to alleviate soreness in the perineum. Some patients will use ice packs the next day or two to reduce swelling. |
