Among prostate cancer patients undergoing a high-tech form of radiation therapy, exposure to a higher amount of radiation over a shorter time span poses no added risk for impaired sexual function, new research reveals.
“For men getting a high dose of radiation in a shorter amount of time than is typical — meaning getting higher doses per day for fewer days — a loss of sexual function is the chronic side effect that concerns most,” noted study co-author Dr. Eric Horwitz, a clinical director in the department of radiation oncology at Fox Chase Medical Center in Philadelphia.
“But we found that sexual function wasn’t any worse than when patients got radiation in the conventional high-dose way,” he said.
Horwitz and lead author Mark Buyyounouski, also at Fox Chase, were expected to present their team’s findings at the annual meeting of the American Society for Therapeutic Radiology and Oncology, in Los Angeles.
The finding comes on the heels of work conducted at Fox Chase last year That study indicated that high-dose radiation should be considered the first line of attack in combating prostate cancer, given that it appears to be the most effective way to limit the disease’s spread.
The team focused on a form of radiation therapy called intensity-modulated radiation therapy (IMRT). According to the American Cancer Society, IMRT is a cutting-edge, 3-D form of high-dose radiation therapy. The treatment is delivered by a computer-controlled machine that moves around the patient to target diseased tissue while avoiding healthy tissue, thereby allowing for the safer use of higher doses of radiation.
In the current study, Horwitz and his colleagues tracked the IMRT radiation treatment outcomes of 155 men diagnosed with intermediate to high-risk prostate cancer.
Half the men were assigned to receive 2 Gray (Gy — a measurement of radiation) in 38 sessions spread over seven and a half weeks.
The other half were exposed to 2.7 Gy in 26 sessions spread over just five weeks.
All the patients then completed questionnaires regarding treatment side effects six months, 12 months, and 24 months following radiation.
Older age, as well as poor sexual function prior to radiation, did increase the risk for sexual impairment after radiation treatment, the researchers said. However, they report no appreciable difference in sexual function between the men receiving the shorter course/higher dose regimen or the more conventional regimen.
“The key to curing more prostate cancer is to give higher does of radiation,” observed Horwitz. “And over the last few years, more and more men have been getting higher dose radiation, because the radiation oncology community knows that dose matters and that low dose radiation is just not effective compared to high dose. And this study shows that we have the ability to give these high doses in different ways, and in all these ways, men do very well.”
Horwitz said he and his colleagues plan to take the current research to the next level.
“We will build on this experience and go with even higher doses,” he said, “to see how that impacts not only sexual function but urinary and bowel function as well.”
Dr. Peter T. Scardino is chairman of the department of urology and head of the Prostate Cancer Program at the Memorial Sloan-Kettering Cancer Center in New York City. He described the finding as a small but important step toward developing shorter course/higher dose radiation therapies.
“This is the trend nowadays,” said Scardino. “This is where this is going: toward a time when perhaps we will be giving radiation therapies all in a single day.”
“Animal studies have already indicated that you may be able to achieve as much or more with a single dose of radiation than with a protracted course,” Scardino noted. “So, the big question is, are you going to find more complications as a result of this kind of a shift in dosage? Now, cutting back from seven and a half weeks to five weeks is a slight move in this direction, but they found no difference in sexual side effects, and that’s valuable. And I certainly think we’ll be seeing a lot more research in this area.”
Prostate Cancer Radiotherapy Won’t Affect Sexual Function
High-dose precision radiation therapy doesn’t harm the sexual function of prostate cancer patients, U.S. researchers say.
A team at Fox Chase Cancer Center in Philadelphia tracked 155 men with intermediate- to high-risk prostate cancer who underwent intensity-modulated radiation therapy (IMRT), a technique that more precisely targets the tumor.
“IMRT is revolutionizing how we treat men with prostate cancer, because it improves our ability to avoid normal tissue. As a result, more radiation dose can be delivered to the prostate by increasing the amount of radiation each day. Increasing the radiation used each day is particularly attractive, because it also shortens the treatment time by several days,” study lead author Dr. Mark Buyyounouski, attending physician in the radiology department at Fox Chase, said in a prepared statement.
“We need to make sure there’s a balance between risk and benefit, and sexual function is a major consideration. Fortunately, this study shows no decrease in sexual function from the higher doses of radiation,” he said.
One group of men in the study received 2 Gy of radiation in 38 sessions over seven weeks, three days, while another group received 2.7 Gy in 26 sessions over five weeks, one day. At six months, one year, and two years after treatment, there were no significant differences in sexual function scores between the two groups.
The findings were expected to be presented Monday at the annual meeting of the American Society for Therapeutic Radiology and Oncology, in Los Angeles.
Prostate Cancer Treatment Options
What are some of the treatment options for prostate cancer?
The treatment options for prostate cancer depend in part on whether the tumor has spread. For tumors that are still inside the prostate, radiation therapy (using x-rays that kill the cancer cells) and a surgery called radical prostatectomy are common treatment options. “Watchful waiting” is also a treatment option. In this approach, no treatment is given until the tumor gets bigger. Watchful waiting may be the best choice for an older man who has a higher risk of dying from something other than his prostate cancer.
Generally, tumors that have grown beyond the edge of the prostate can’t be cured with either radiation or surgery. They can be treated with hormones that slow the cancer’s growth.
What is radical prostatectomy?
Radical prostatectomy is a surgery to remove the whole prostate gland and the nearby lymph nodes. Most men who have this surgery are under general anesthesia (puts you into a sleep-like state). After the prostate gland is taken out, a catheter (a narrow rubber tube) is put through the penis into the bladder to carry urine out of the body until the area heals.
What are the risks and benefits of radical prostatectomy?
If you’re in good health, the short-term risks of this surgery are low. The hospital stay is usually 2 to 3 days, with the catheter left in place for 2 to 3 weeks. You’re usually able to go back to work in about 1 month. You shouldn’t have severe pain with this surgery. Most men regain bladder control a few weeks to several months after the surgery.
The main advantage of surgery is that it offers the most certain treatment. That is, if all of the cancer is removed during surgery, you are probably cured. Also, the surgery provides your doctor with accurate information about how advanced your cancer is, since the nearby lymph nodes are taken out along with the tumor.
Surgery does have risks and complications. You could lose a lot of blood during this surgery. Before the surgery, you might want to save about 2 units of your own blood in case you need a transfusion. The main risks of this surgery are incontinence (lack of bladder control) and impotence (loss of the ability to get or keep an erection long enough to have sex). Fortunately, only a very low percentage of men have severe incontinence after radical prostatectomy. Up to 35% of men have a little accidental leakage of urine during heavy lifting, coughing or laughing.
The chance of impotence decreases if the surgeon is able to avoid cutting the nerves. This may not be possible if the tumor is large. Your age and degree of sexual function before the surgery are also important factors. If you’re under 50 years old when you have this surgery, you’re likely to regain sexual function. If you’re older than 70, you’re more likely to lose sexual function. Remember, even if the nerves are cut, feeling in your penis and orgasm remain normal. Only the ability to get a rigid penis for sexual intercourse is lost. However, there are medicines and devices that can help make the penis rigid.
What is radiation therapy? What are its risks and benefits?
There are 2 types of radiation therapy. In one type, called external beam radiation therapy, radiation is given from a machine like an x-ray machine. In another type, radioactive pellets (called “seeds”) are injected into the prostate gland. This is sometimes called seed therapy or brachytherapy. Both types work about the same in curing prostate cancer.
The machine therapy is usually given 5 days a week over 7 weeks, which you might find time-consuming. However, you don’t need any anesthesia. The side effects are milder than the side effects that can come with seed therapy. However, seed therapy can be done with just one hospital visit. For seed therapy, you have to have anesthesia for a few minutes, but you should be able to go home right after the treatment. In seed therapy, higher doses of radiation can be put right on the cancer. You may feel more discomfort after this treatment.
About one half of patients become impotent within 2 years of having radiation therapy. Many men feel very tired at the end of the treatment period. About 15% to 30% of men who have radiation therapy have urinary burning, urinary bleeding, frequent urination, rectal bleeding, rectal discomfort or diarrhea during or shortly after the treatment. Serious complications are rare. However, a degree of uncertainty goes along with radiation treatment. Since the prostate gland and the lymph nodes are not taken out, your doctor can’t tell the exact size of the tumor. The cancer could come back many years after radiation treatment.
At 10 years after treatment, cure rates are about the same for radiation therapy and radical prostatectomy. There are no surgical risks for men who have radiation therapy. There’s no risk of bleeding. You don’t have to stay in the hospital. You’ll recover faster. Daily activities can usually go on during the treatment. Incontinence is extremely rare afterward. However, surgery may give you a better chance of cure over the long term.
What are the risks and benefits of watchful waiting?
Many prostate cancers are small and grow slowly. Because many men with a slow-growing tumor have the same life expectancy as men who don’t even have prostate cancer, it may not be necessary to treat very small, very slow-growing prostate tumors. Also, some men feel that the side effects of treatment outweigh the benefits. In watchful waiting, you get no treatment, but you see your doctor often. If there’s no sign the cancer is growing, you continue to get no treatment. Hormone therapy can be started if the cancer starts to grow.
It can be hard to tell if a small tumor is going to grow slowly or quickly. Your doctor will get clues about the way your tumor will grow by checking your prostate-specific antigen (PSA) level, examining the biopsy tissue and giving you a rectal exam. The choice of watchful waiting is up to you.
What is the purpose of hormone therapy?
The purpose of hormone therapy is to lower the level of the male hormones, called androgens, which are produced mostly in the testicles. This is because androgens, such as testosterone, help the prostate tumor grow. Monthly shots can be given or the testicles can be surgically removed. Once the testosterone is out of your body, the prostate cancer usually shrinks. Hormone treatments are most often used in patients with cancer that has already spread beyond the prostate gland.
While prostate cancer usually responds to 1 or 2 years of hormone therapy, after some time most tumors start to grow again. Once this happens, the treatment goal is to control symptoms. No treatment can cure prostate cancer after hormone therapy stops helping.
What happens after prostate cancer treatment?
You should get PSA (prostate-specific antigen) blood tests every 6 months for 5 years, and then once every year. A rise in PSA levels usually means that the cancer has come back. A digital rectal examination should be done once a year.
Where can I get more information about prostate cancer?
Your family doctor, your oncologist (cancer doctor), the radiotherapist and your urologist can give you information. Your local hospital or cancer center may refer you to a local prostate cancer support group, where you can meet other men who have had this cancer.
