Long-term QOL outcomes 4 years after PBRT

In a poster today at the Genitourinary Cancers Symposium, data was presented on 4-year follow-up of quality of life (QOL) among men treated with conformal proton beam radiation therapy (PBRT).

Coen et al. administered serial QOL questionnaires to a cohort of men being treated with PBRT. The men were stratified into functional groups based on information from their baseline questionnaires (normal, intermediate or poor function) for each symptom domain. Symptom scores were then calculated at baseline and at long-term follow-up and expressed as mean values.

Here is what Coen and his colleagues found:

  • 72 patients completed questionnaires for at least 2 years.
  • Average (median) age at treatment was 66 years
  • Average (median) follow-up was 44 months.
  • Average (median) dose of PBRT was 82 GyE (range, 74 to 82 GyE).
  • All 72 patients showed increased scores for
    • Incontinence (3.2 baseline vs. 9.9 long-term, p < 0.001)
    • Obstructive/irritative voiding (20 vs. 24, p = 0.028)
    • Bowel dysfunction (4.4 vs. 8.0, p = 0.001)
    • Sexual dysfunction (25 vs. 48, p < 0.001).

More specific estimates were possible when patients were stratified by initial functional category:

  • For incontinence, only normal function was associated with a significant increased score (0 vs. 8.4 at baseline and long-term, p < 0.001).
  • For obstructive/irritative voiding, only normal baseline function showed a significantly increased score (12 vs. 17, p = 0.01).
  • For bowel dysfunction, only men with normal baseline function had a significantly increased score (0 vs. 5.4, p < 0.001).
  • For sexual dysfunction, the score increased in men with normal (1.4 vs. 30, p < 0.001) and intermediate function (17 vs. 46, p < 0.001). 

As far as we are aware, this is the first-ever set of patient-reported quality of life data demonstrating the long-term consequences of PBRT monotherapy for prostate cancer.

High-dose proton radiation was clearly associated with small increases in bowel dysfunction, in obstructive/irritative voiding dysfunction and incontinence. After long term follow-up, sexual dysfunction appears to have increased more than any other quality of life indicator. However, sexual dysfunction can be associated as much with the aging process as with specific forms of treatment, so in a series of this size it is difficult to know white how much loss of erectile function can be associated with PBRT carried out about 4 years previously.

6 Responses

  1. How does that compare with QOL studies on IMRT and IGRT?

    The big problem, as Sitemaster rightfully points out, is how to isolate procedure-related QOL from normal, age-related ones. It seems it would require the study of a huge number of people, for a long time, and stratified by age and other factors. Meanwhile, as usual, it’s a personal choice.

  2. Thanks for reporting this.

    Can anyone give some information about what the scores meant – what’s zero, mild, moderate, etc.?

    I’m also wondering when we will get some longer-term cancer control results from Loma Linda, something around the 10-year mark.

  3. Reuven: It simply isn’t possible to answer how these data compare to data from QOL studies on IMRT and IGRT. I think the only conclusion one can draw from this study is that PBRT is associated with a range of long-term side effects in some patients.

  4. One of the authors told me this morning that this paper has been submitted for publication and more detail will be available in the full publication.

    With respect to getting further data from Loma Linda … I have little confidence that this will happen.

  5. Something doesn’t add up with, “Average (median) dose of PBRT was 82 GyE (range, 74 to 82 GyE).”

  6. Dave:

    You are correct. The actual poster (of which I now have a copy) states:

    “32 men received 82 GyE; 40 received a median dose of 78 GyE (range, 74-79).”

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