Urologic Oncology: Radiation Oncology
Radiation therapy for prostate cancer can be administered in two different ways at St. Joseph Hospital – internally by permanent radioactive seed implant, externally with high-energy radiation beams, or a combination of both, depending on the patient’s disease prognosis. Our highly skilled radiation oncologists and experienced physicists/ dosimetrists work closely together to devise individualized treatment plans to ensure accurate delivery of radiation to the tumor while minimizing the toxicity to the surrounding healthy tissues, such as the rectum and bladder.
Brachytherapy (Radioactive Seed Implant)
This minimally invasive, localized therapy is a one-time outpatient procedure that involves implanting small radioactive pellets, or “seeds,” about the size of a grain of rice into the prostate, where they deliver radiation from inside the gland for a number of months. Brachytherapy may be used alone or in conjunction with external beam radiation. The seeds are so small that they cause no discomfort. The patient receives anesthesia before the seeds are implanted. Then needles are inserted through the skin of the perineum (the space between the scrotum and anus) under ultrasound guidance. The seeds are placed into the prostate though these needles using a special applicator. “Real-time” intra-operative dosimetry is used to ensure sufficient radiation dosage is delivered to the prostate for optimal efficacy, but with minimal dosage to the adjacent healthy tissues. The outcomes for early stage prostate cancer are similar between brachytherapy and surgery. A multidisciplinary team of medical experts works with each patient to prepare for this procedure and provide follow-up care and guidance. This team includes a radiation oncologist, urologist and physicist/ dosimetrist who determine the proper dosage.
Three-Dimensional Conformal Radiation Therapy (3D-CRT)
Three-dimensional conformal radiation therapy is a form of external-beam radiation that shapes the radiation beam to the contours of the tumor, allowing for high doses of radiation to be precisely delivered to the cancer while sparing surrounding healthy tissues. This technique delivers radiation to the entire prostate plus a margin to ensure that any existing peripheral prostate cancer cells are treated. Treatments are generally administered five days per week for seven to eight weeks.
Intensity Modulated Radiation Therapy (IMRT)
St. Joseph Hospital was among the first in Orange County to offer fully integrated Intensity Modulated Radiation Therapy (IMRT,) which is a more sophisticated extension of conformal radiotherapy. The state-of-the-art technology utilizes an advanced treatment planning computer system to develop a targeted therapy plan based on the location, shape and size of the tumor. The precision of this technology allows increased radiation dose to the prostate while minimizing to normal tissue and hence side effects. This form of treatment is usually offered in conjunction with image guided radiation therapy (see below).
Image-guided Radiation Therapy (IGRT)
In addition to IMRT, patients who receive radiation for prostate cancer at St. Joseph Hospital also are treated with image-guided radiotherapy or IGRT. Two to three non-radioactive gold seeds are placed in the prostate before treatment. These seeds can be tracked on a daily basis (a kind of “GPS” for prostate location.) This allows for a more focused and accurate radiation beam, which further minimizes side effects from treatment.
Side effects of radiation for prostate cancer are primarily related to nearby normal tissue (e.g. bladder and rectum). The patient may experience mild discomfort with urination, increased frequency and urgency with urination as well as more frequent and loose bowel movements. The side effects usually subside once radiation is completed.
The St. Joseph Hospital Department of Radiation Oncology is a member of RTOG (Radiotherapy Oncology Group) and offers prostate cancer patients clinical trials through this research group.