External beam radiation therapy is a method for delivering a beam of high-energy X-rays to the location of the patient's tumor. The beam is generated outside the patient (usually by a linear accelerator) and is targeted at the tumor site. Careful treatment planning allows the surrounding normal tissues to be spared.
Holy Cross Hospital Expertise
The Holy Cross Hospital Radiation Treatment Center uses high-energy linear accelerator including the VarianT 2100EX and Novalis® image-guided radiotherapy (IGRT) system. External beam radiation is usually delivered with intensity-modulated radiation therapy (IMRT)-a technique that allows our radiation oncologists to carefully conform the radiation dose around the prostate gland, thereby sparing normal tissues.
The Novalis system also offers another key feature to improve radiation therapy for prostate cancer. Because the prostate gland can move as one inch in various directions depending on how much urine is in the bladder or how much gas or stool is in the rectum, it is very important that the radiation oncology team carefully target it. The Novalis system employs the sophisticated ExacTrac® software system, which relies on marker seeds to target the prostate immediately prior to treatment. The ExacTrac system allows our radiation oncologists to treat less bladder and rectum by using tighter margins around the prostate gland, since the targeting technology is so precise.
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Patients with prostate cancer who are treated for with external beam radiation therapy are treated as outpatients, five days a week for eight to nine weeks. Treatments take 10 to 30 minutes per day. These treatments are painless. It is similar to having an X-ray. There is no nausea. Patients are able to carry on their normal activities, work full-time, and drive themselves to and from treatment.
When patients are receiving external beam radiation, as far as the general public goes, there are no safety procedures that need to be followed. Once the treatment is completed and the machine is turned off, there is no radiation in the room and no radiation in your body. Therefore, you do not need to worry about contact with children, pregnant women or anybody else.
Possible Side Effects
Between the third and fifth weeks of external beam radiation therapy, most patients will experience mild to moderate urinary symptoms. These include urinary frequency (especially at night), burning on urination and a weak stream. Very rarely patients will have bleeding. These symptoms can be partially relieved with medications. They are rarely severe.
During this same time frame, most patients experience mild to moderate anal-rectal symptoms. These include frequent small stools, rectal urgency, rectal irritation, excessive gas and bleeding. Patients with hemorrhoids are more likely to be bothered, especially with bleeding and discomfort. There are medications for these symptoms.
Additional complaints include mild to moderate fatigue, hair loss in the irradiated area (not on the head), and very mild skin reddening. Patients may need one to two hours of extra sleep or a nap.
Most, if not all, of these symptoms resolve three to six weeks after completion of radiation.
Long-term complications include erectile dysfunction (20 to 40 percent), chronic rectal bleeding (5 to 10 percent), rectal urgency and frequency (5 percent, hip fracture (1 to 2 percent), urinary bleeding (less than 1 percent) and urinary incontinence (less than 1 percent). Rectal bleeding can usually be treated successfully with suppositories. HEMORRHOID SURGERY AND CAUTERY FOR RECTAL BLEEDING MUST BE AVOIDED SINCE MAJOR COMPLICATIONS MAY OCCUR. NEW LASER TREATMENTS MAY BE SAFE BUT SHOULD BE USED WITH CAUTION.
Erectile dysfunction (ED) is the most common complication following all treatments of prostate cancer. The good news is that most cases of ED following external beam radiation can be successfully treated with medication (Viagra, Levitra or Cialis). If a patient has good erections prior to treatment, the probability that he will maintain an erection satisfactory for sexual intercourse after treatment is about 80%; however, many patients will use one of these medications at least some of the time. If the erection is already impaired prior to radiation therapy, these drugs are less likely to work. If they are unsuccessful, other treatments such as penile injections may prove effective.