Acute and mid-term side effects of high-dose, image-guided IMRT in first-line treatment of localized prostate cancer


Two recent papers have reported data relevant to the application of high-dose, image-guided, intensity-modulated forms of radiation therapy (IGRT/IMRT) in the first-line treatment of men with localized prostate cancer.

In the first of these papers, Eade et al. discuss data from their series of 101 men with localized disease, all treated with curative intent with IGRT/IMRT at doses ranging from 78.3 to 84.0 Gy (median, 79.3 Gy).

The authors report the following results:

  •  The average (median) age of the patients was 71 years (range, 46-83 years).
  • 60 percent of the men received concurrent androgen deprivation therapy (ADT).
  • 35 percent of the men also had radiation for treatment of their pelvic lymph nodes.
  • The median International Prostate Symptom Scores (IPSS) were
    • 7 (range, 0 to 35) at baseline
    • 15 (range, 1 to 34) on treatment
    • 6 (range, 0 to 30) at first follow-up
  • Grade 2 or higher levels of gastrointestinal toxicity and consequent side effects were observed in
    • 6.9 percent of patients during treatment
    • 1.0 percent of patients at 3 months post-treatment
    • 3.0 percent of patients at 2 years post-treatment
  • Grade 2 or higher levels of genitourinarytoxicity and consequent side effects were observed in
    • 39.0 percent of patients during treatment
    • 6.9 percent of patients at 3 months post-treatment
    • 3.0 percent of patients at 2 years post-treatment% for genitourinary symptoms.
  • No significant difference in gastrointestinal toxicity was observed between patients who did or did not have lymph node radiation either during treatment (P = 0.860) or at 3 months post-treatment (P = 0.334).

In this study, doses of > 78 Gy delivered using daily image guidance and IMRT are well tolerated. Within 3 months post-treatment, acute and short-term side effects had normalized for the majority of patients.

In the second of the two papers, Gill et al. report on data on acute toxicity from a series of 249 patients, again all treated for localized prostate cancer (between 2006 and 2009) with first-line IGRT/IMRT at total doses of between 74 and 78 Gy, and compared to data from 26 men treated without IGRT at the same dose levels. Data were collected on 10 different acute side effects of therapy using standardized procedures.

The results of this study were that:

  • In the IGRT/IMRT group
    • 14,228 toxicity scores were analysed from 249 patients.
    • Urinary frequency of Grade 3 and higher affected 7 percent of patients.
    • Diarrhea of Grade 2 and higher affected 3 percent of patients.
    • Fatigue of Grade 2 and higher affected 8 percent of patients.
  • In the non-IGRT/IMRT group, 1,893 toxicity scores were analysed from 26 patients.
    • Urinary frequency of Grade 3 and higher affected 23 percent of patients.
    • Diarrhea of Grade 2 and higher affected 15 percent of patients.
    • Fatigue of Grade 2 and higher affected 23 percent of patients.
  • Differences between the IGRT/IMRT and the non-IGRT/IMRT groups for other forms of acute toxicity (including cystitis, bladder spasm, urinary incontinence, urinary retention, diarrhea, hemorrhoids, proctitis, and anal skin discomfort) were not statistically significant.

In this study, patients treated radically with modern forms of image-guided IMRT had less severe levels of acute urinary frequency, diarrhea, and fatigue during treatment compared to patients treated with non-image-guided IMRT and the onset of these symptoms occurred later in the image-guided IMRT group of patients.

The two studies, taken in combination, demonstrate the reduction in acute and mid-term side effects of modern, image-guided forms of IMRT, even when used at very high dose levels, compared to non-image-guided forms of IMRT.

2 Responses

  1. Since there are many kinds of image guidance, it would be of interest to know how it is defined here and whether, when called “IGRT,” it has a very specific meaning, i.e. a generally accepted definition.

  2. The paper by Eade et al. does not refer to a specific type of image guidance in the abstract. The abstract of the paper by Gill et al. refers specifically to “fiducial marker IGRT.”

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