Prostate Cancer: Latest Treatments and Emerging Therapies
What's involved with radiation for early-stage prostate cancer? continued...
Proton beam therapy is a type of external radiation therapy. It involves the use of a tightly focused beam of protons. These are atomic particles with a positive electric charge. The advantage of this type of therapy is that the beam delivers most of its energy to the target tissue. That spares surrounding, healthy tissues from large doses of radiation. This type of therapy is more expensive than the non-proton radiation techniques in common use. It's offered in only a few treatment centers in the United States and may not be covered by insurance. Right now, there is no clear evidence from patient studies that suggests that proton beam therapy is better than standard radiation techniques though there is a definite theoretical advantage for proton therapy.
Modern radiation therapy is often done with a conformal technique. That's a technique in which three-dimensional imaging systems map out the shape of the prostate tumor. That allows for more precise delivery of high-dose radiation directly to the tumor. At the same time, it minimizes exposure to nearby healthy structures such as the bowel or urinary tract. A refinement of conformal radiation therapy is called intensity-modulated radiation therapy (IMRT). IMRT allows more precise delivery of high-energy radiation to the tumor with lower exposure of healthy tissues. Doing so often results in a lower incidence of side effects in the urinary tract or bowel.
For low-risk prostate cancers, good treatment options include radiation in the form of brachytherapy or external beam radiation treatment such as IMRT or proton therapy. Cure rates for radiation compare favorably to those of prostatectomy. There have been no major head-to-head studies that compare the effectiveness of surgery and radiation therapy for low-risk prostate cancer. But there is general agreement that patients should not select a therapy based on comparative cure rates. Rather, men should consider the possibility of side effects and the impact they may have on their quality of life.
What are the complications and side effects of radiation?
Common complications of radiation therapy include erectile dysfunction and urinary incontinence. Erectile dysfunction after radiation tends to improve more gradually than after surgery. But newer radiation techniques have lowered the risk of long-term erectile dysfunction.