Clinical Experience With Intensity Modulated Radiation Therapy (IMRT) in Prostate Cancer

Radiother Oncol. 2000 Jun;55(3):241-9. doi: 10.1016/s0167-8140(99)00100-0.

Abstract

Purpose: To compare acute and late toxicities of high-dose radiation for prostate cancer delivered by either conventional three-dimensional conformal radiation therapy (3D-CRT) or intensity modulated radiation therapy (IMRT).

Materials and methods: Between September 1992 and February 1998, 61 patients with clinical stage T1c- T3 prostate cancer were treated with 3D-CRT and 171 with IMRT to a prescribed dose of 81 Gy. To quantitatively evaluate the differences between conventional 3D-CRT and IMRT, 20 randomly selected patients were planned concomitantly by both techniques and the resulting treatment plans were compared. Acute and late radiation-induced morbidity was evaluated in all patients and graded according to the Radiation Therapy Oncology Group toxicity scale.

Results: Compared with conventional 3D-CRT, IMRT improved the coverage of the clinical target volume (CTV) by the prescription dose and reduced the volumes of the rectal and bladder walls carried to high dose levels (P<0.01), indicating improved conformality with IMRT. Acute and late urinary toxicities were not significantly different for the two methods. However, the combined rates of acute grade 1 and 2 rectal toxicities and the risk of late grade 2 rectal bleeding were significantly lower in the IMRT patients. The 2-year actuarial risk of grade 2 bleeding was 2% for IMRT and 10% for conventional 3D-CRT (P<0.001).

Conclusions: The data demonstrate the feasibility and safety of high-dose IMRT for patients with localized prostate cancer and provide a proof-of-principle that this method improves dose conformality relative to tumor coverage and exposure to normal tissues.

Publication types

  • Clinical Trial
  • Comparative Study
  • Randomized Controlled Trial
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Aged
  • Aged, 80 and over
  • Feasibility Studies
  • Humans
  • Male
  • Middle Aged
  • Neoplasm Staging
  • Prostatic Neoplasms / pathology
  • Prostatic Neoplasms / radiotherapy*
  • Radiotherapy Planning, Computer-Assisted*
  • Radiotherapy, Conformal / methods*
  • Radiotherapy, Conformal / standards
  • Safety