For much of its history, radiation therapy for cancer has involved dosing the region of a patient’s body surrounding a tumor with high doses of radiation. This has tended to increase recovery time and diminish quality of life for the patient, both during and following treatment. There are now far more intricate techniques available that enable a radiation oncologist to pinpoint beams of radiation, with sub-millimeter accuracy, to the core of a tumor, allowing more of the surrounding healthy organs to be spared. While these novel regimens have reduced the typical side effects of radiation, they have not eliminated them entirely. For prostate cancer, in particular, there are still considerable challenges. Nathan Tennyson, MD, and Raj Rajpara, MD, radiation oncologists at Jupiter Medical Center (JMC), discuss with Pinnacle Magazine how prostate cancer is being treated, and how progress is being made in addressing the side effects through the use of a new hydrogel product.
Can you discuss the prevalence of prostate cancer and its survival rates?
Rajpara: It still is the most common cancer diagnosis in men in the United States. About 1 in 9 men are diagnosed with prostate cancer at some point in their lives. We have new, sophisticated ways we can treat it, and with the appropriate treatment, survival is improving. More and more patients are being cured and prostate cancer–specific mortality is decreasing with appropriate treatment. Bowel toxicity is a major factor in radiotherapy for prostate cancer.
Can you talk about how and why rectal toxicity occurs, and what some of the symptoms are?
Tennyson: For men who undergo prostate radiotherapy, there’s always a portion of the rectum that’s exposed to radiation therapy—because the rectum is very close to the prostate itself, and some of it, unfortunately, is included in the radiation therapy field. It’s unavoidable, and that’s really what causes the side effects. Those symptoms typically include bowel urgency and diarrhea. These are the acute side effects, meaning they occur during the treatment. There are also potential long-term side effects, including rectal bleeding, which used to be more common before technology got better but still can happen today. There are some very fragile blood vessels in the radiation field, and those can bleed years after the radiation is done. SpaceOAR Hydrogel can alleviate a lot of the side effects involving rectal toxicity.
Can you discuss the SpaceOAR Hydrogel procedure and what it accomplishes?
Rajpara: SpaceOAR Hydrogel is an outpatient procedure that takes about 10 to 15 minutes. We do it at the same time as fiducial marker placement, which is used to help target and track the prostate during radiation treatment. We inject the gel in the space between the prostate and the rectum using an ultrasound for guidance. Patients go home the same day. The gel solidifies once it’s in the body and stays in the body for about three to six months. [While it’s in], it increases the space between the prostate and the rectum by about 1 to 2 centimeters. With radiation, even a few millimeters are a big deal because of the way the radiation beams are designed. A few millimeters of space can dramatically decrease the dose going to the rectum, so you can imagine 2 centimeters—that’s a lot of space. So, what that does is it helps prevent those rectal side effects during radiation, but more importantly, also those long-term side effects. The studies show that the gel also improves quality of life in terms of sexual dysfunction and urinary symptoms.
Because of the insulation provided by the SpaceOAR Hydrogel, are you able to give a larger single dose?
Tennyson: Yes and no. There are three courses of radiation: a nine-week, 44-treatment course; a middle-of-the-road, 28-treatment course; and then a five-treatment, Cyberknife-based radiation treatment. For those patients getting the shorter courses, the dose of radiation is larger, so we do recommend SpaceOAR Hydrogel a bit more for those patients, because I am concerned about the rectal toxicity in that group. It’s made me more willing to do the shorter courses because I know the rectum will be protected.
SpaceOAR Hydrogel has been in use for about a year at JMC. Are other medical centers, locally or regionally, using it as well?
Rajpara: There are a few other centers in Palm Beach County that are doing it, but in terms of major hospitals that are performing it, no, I can’t think of any. We’ve had a lot of patients that come to our offices just because we offer it and other centers do not.
Is there anything that’s come up in the last year that you’d like to add?
Tennyson: For patients with prostate cancer, we want to minimize the side effects. We want to minimize the time that the patients are here, because they’d rather be doing other things, and SpaceOAR Hydrogel is one more tool available to us to do that.