In a nutshell
This study compared the safety and effectiveness of two forms of imaging-guided radiation techniques for prostate cancer. Researchers reported more favorable outcomes with intensity modulated radiation therapy (IMRT) than with 3-dimensional conformal radiation therapy (3DCRT).
Some background
Radiation therapy is a common treatment for localized (confined) prostate cancer. It involves directing high-energy rays at the tumor site to kill cancer cells. Gradually increasing the doses of radiation (known as dose escalation) provides better cancer control. This is often recommended in cases of increased risk of cancer recurrence. However, higher doses of radiation are often linked to significant side effects, mostly affecting the stomach, bowel, or urinary function.
Three-dimensional conformal radiation therapy (3DCRT) has been developed as a possible alternative. 3DCRT uses 3-dimensional images of the tumor to target radiation precisely at the tumor site. The surrounding healthy tissue receives less radiation, thereby reducing the chance of side effects. Intensity modulated radiation therapy (IMRT) is an advanced form of 3DCRT. IMRT takes into account different parts of the tumor and can deliver higher doses of radiation to more aggressive tumor cells. However, the potential benefits of IMRT over 3DCRT for prostate cancer treatment have not been fully studied.
Methods & findings
This study pooled the results of 23 separate trials into a single analysis to compare IMRT and 3DCRT. The analysis included a combined total of 9,556 men with prostate cancer. Side effects (grade 2 to 4) as well as treatment effectiveness were compared between IMRT and 3DCRT.
IMRT significantly reduced early-onset gastrointestinal (involving the stomach and intestines) side effects by 41% compared to 3DCRT. Lasting gastrointestinal side effects were also reduced by 46% with IMRT. This remained significant for up to 10 years after treatment.
Side effects relating to the genitals and urinary organs were comparable between between IMRT and 3DCRT. No differences in early-onset rectal bleeding were observed between the two radiation methods. However, IMRT was associated with a 52% reduced risk of lasting rectal bleeding problems compared to 3DCRT.
IMRT was associated with significantly greater treatment response (based on blood tests) compared to 3DCRT (by about 17%). No differences in overall survival (time from treatment until death from any cause) were observed.
The bottom line
Researchers concluded that IMRT was associated with fewer side effects and better treatment response than 3DCRT.
Published By :
PLOS ONE
Date :
May 12, 2016
