In the study conducted at Fox Chase Cancer Center in Philadelphia, researchers analysed data collected prospectively from 1,417 patients. Of these, 928 men were treated with three-dimensional conformal radiation therapy (3D CRT) - median follow-up of 63.3 months - and 489 men with intensity-modulated radiation therapy (IMRT) - median follow-up of 29.9 months. The IMRT patients received higher doses of radiation.

Patients were matched for PSA level (prostate specific antigen, measured by a blood test and used to determine if prostate cancer is present), T-stage (palpable size) and Gleason score (tumour aggressiveness determined by pathologic testing). The researchers evaluated gastrointestinal side effects such as short-term diarrhea and longer-term bowel dysfunction and genitourinary side effects such as urinary frequency, urgency and, rarely, painful or difficult urination or obstructive symptoms.

"There were no differences in the reporting of acute gastrointestinal or genitourinary side effects for the two treatment modalities," explained Alexander Kirichenko, M.D., Ph.D., lead author of the study. "However, as the data are beginning to mature, we're seeing more long-term gastrointestinal side effects in the men treated with 3D CRT." Even though patients treated with IMRT had higher doses of radiation, there were fewer gastrointestinal side effects three years after treatment. The research showed no statistically significant difference between the two treatment types for genitourinary side effects.

Kirichenko concluded, "Despite the specific findings pertaining to 3D CRT technique and the gastrointestinal side effects, men treated with either modality have acceptable rates of side effects at this point in our analysis particularly when compared to data from surgical outcomes."

MEDICA.de; Source: Fox Chase Cancer Center