Incidence of late rectal and urinary toxicities after three-dimensional conformal radiotherapy and intensity-modulated radiotherapy for localized prostate cancer

Int J Radiat Oncol Biol Phys. 2008 Mar 15;70(4):1124-9. doi: 10.1016/j.ijrobp.2007.11.044.


Purpose: To report the incidence and predictors of treatment-related toxicity at 10 years after three-dimensional conformal radiotherapy (3D-CRT) and intensity-modulated radiotherapy (IMRT) for localized prostate cancer.

Methods and materials: Between 1988 and 2000, 1571 patients with stages T1-T3 prostate cancer were treated with 3D-CRT/IMRT with doses ranging from 66 to 81 Gy. The median follow-up was 10 years. Posttreatment toxicities were all graded according to the National Cancer Institute's Common Terminology Criteria for Adverse Events.

Results: The actuarial likelihood at 10 years for the development of Grade>or=2 GI toxicities was 9%. The use of IMRT significantly reduced the risk of gastrointestinal (GI) toxicities compared with patients treated with conventional 3D-CRT (13% to 5%; p<0.001). Among patients who experienced acute symptoms the 10-year incidence of late toxicity was 42%, compared with 9% for those who did not experience acute symptoms (p<0.0001). The 10-year incidence of late Grade>or=2 genitourinary (GU) toxicity was 15%. Patients treated with 81 Gy (IMRT) had a 20% incidence of GU symptoms at 10 years, compared with a 12% for patient treated to lower doses (p=0.01). Among patients who had developed acute symptoms during treatment, the incidence of late toxicity at 10 years was 35%, compared with 12% (p<0.001). The incidence of Grade 3 GI and GU toxicities was 1% and 3%, respectively.

Conclusions: Serious late toxicity was unusual despite the delivery of high radiation dose levels in these patients. Higher doses were associated with increased GI and GU Grade 2 toxicities, but the risk of proctitis was significantly reduced with IMRT. Acute symptoms were a precursor of late toxicities in these patients.

MeSH terms

  • Aged
  • Aged, 80 and over
  • Follow-Up Studies
  • Humans
  • Incidence
  • Male
  • Middle Aged
  • Proctitis / etiology
  • Prostatic Neoplasms / radiotherapy*
  • Radiation Injuries / epidemiology*
  • Radiation Injuries / pathology
  • Radiotherapy Dosage
  • Radiotherapy, Conformal / adverse effects*
  • Radiotherapy, Intensity-Modulated / adverse effects
  • Rectum / radiation effects*
  • Time Factors
  • Urinary Bladder / radiation effects*
  • Urogenital System / radiation effects