In its simplest form, Seed implant therapy for prostate cancer is a curative form of treatment where radioactive material are placed within the prostate gland. The radiation doses around these sources are huge and are not achievable by any other method of radiation. By exposing cancer cells to this amount of radiation, it does make intuitive sense that this should achieve higher cancer cure rates compared to other forms of treatment.
A Brief History: This procedure was first utilized in the 1970's at several cancer centers throughout the country. Unfortunately, lack of good imaging of the prostate caused inaccurate placement of these seed implants as well causing less than optimal control of these cancers as well as producing horrendous side effects.
What has changed now? With improved imaging with ultrasound technology and high quality computer software, it is now possible to place the radiation seeds a lot more accurately resulting in improved predictability of cancer control and side effects.
What kind of Patients will this work in? Patients with Prostate cancer who are predicted to have a high probability of cancer confined to the prostate can be offered this form of treatment alone.
What about patients who have more advanced disease?: In those patients where the cancer is a little more advanced, but not widespread, can be offered this form of treatment in addition to a 5 week course of external beam radiation therapy. The 5 week course of external radiation therapy allows us to "mop" up cancer cells that may have migrated beyond the capsule of the prostate gland and / or may have spread into the lymph glands surrounding the prostate. The radiation from the seed implant procedure is unable to reach these cancer cells that have escaped beyond the prostate gland. Hence, the combination of both external beam radiation with the seed implant procedure does make a lot of intuitive sense in this group of patients.
What are the types of prostate seed implant procedures that are available?
There are basically two types of procedures.
1) Permanent seed implants: Radioactive seeds are placed within the prostate gland uniformly and left in place forever. The radiation from these seeds are given out slowly over a period of days to months which kills cancer cells. The most common radioactive material that are used in this procedure include radioactive iodine and radioactive palladium. Each of these elements have their own unique characteristics but none have been found superior over the other. The inert seeds which run out of radioactivity remain within the prostate and are harmless. The patient is radioactive for the first one to two months after the procedure, hence prolonged contact with young children and pregnant women should be avoided during this time.
2) Temporary seed implants: Radioactive seeds are placed within needles and catheters that are placed within the prostate gland through a procedure called HDR Brachytherapy. These are then connected to an HDR machine which moves radioactive Iridium into the needles and catheters to different positions within the prostate for specified durations. The total irradiation time is usually only about 10 to 15 minutes. Once the procedure is completed, the catheters and needles are removed and the patient is allowed to go home. This procedure is generally done in two or more sessions to allow delivery of appropriate amounts of radiation to the prostate.
Prostate cancer patients where seed implant is a relative contra-indication: There are certain situations that seed implant becomes problematic. These are those patients who have:
1. undergone a TURP procedure.
2. The anatomy of the pelvis causes what is called pubic arch interference which makes the placement of seeds very difficult to cover the entire gland.
3. Major urinary bladder outlet obstructive symptoms. This again is reflective of the size of the gland making uniform distribution of the seed implant difficult.
4. Obese patients. Procedure becomes difficult and may not allow appropriate distribution of radiation with optimal effects.
What are the problems with seed implant procedure for Prostate cancer? It is an operating room procedure requiring anesthesia, the help of a Urologist, Radiation Oncologist and Physicist. As in any kind of operating procedure, there are inherent risks of any kind of surgery such as bleeding, infection etc.
Is the Seed implant procedure better than other forms of radiation therapy? There are no studies comparing seed implant treatment of prostate cancer with other forms of radiation. So, the answer is still unknown and most likely will never be known. All we can say at this time is that prostate seed implant procedure is not inferior to other forms of radiation treatment and so it will be basically be up to the patient and the consulting radiation doctor to decide on what is best for each individual situation.
Dr. Kumar is a board certified Radiation Oncologist who is co-founder of a private practice group in Florida. He has over 17 years experience dealing with cancer patients including several members in his own family who have been afflicted by this disease.
His philosophy of managing patients is through a unique holistic approach that takes into account the wishes and needs of patients and their families. He believes that any battle is won at the level of the mind first before the body goes into action to win the war. His website http://curingcancerofthemind.com/ reflects this philosophy.
He is always available to help any patient with questions regarding cancer and radiation therapy and can be reached at 772 293 0377.
