Brachytherapy boost may lower mortality rate in high-risk patients

The ASCENDE-RT randomized clinical trial demonstrated that the combination of external beam radiation therapy with a brachytherapy boost (EBRT + BT) significantly reduced biochemical progression-free survival. A new data analysis suggests that this benefit may extend to prostate cancer survival as well.

>Xiang and Nguyen searched the SEER database to identify 52,535 high- and intermediate-risk patients who were treated with EBRT + BT or EBRT alone between 2004 and 2011. Of that total, 20 percent received EBRT + BT, and one-third were high risk. They matched patients for risk factors, and adjusted for other variables that affect survival.

By 8 years after treatment, the adjusted prostate cancer-specific mortality (PCSM) rates were:

  • 8 percent for EBRT + BT
  • 7 percent for EBRT alone
  • 4 percent for EBRT + BT among high-risk patients
  • 6 percent for EBRT alone among high-risk patients
  • Mortality was not significantly reduced among intermediate-risk patients

The authors conclude:

BT boost was associated with a moderate reduction to PCSM in men with localized unfavorable-risk prostate cancer. Those most likely to benefit are younger patients with high-risk disease.

Of course, this was a database analysis and not a randomized clinical trial, so the findings are provisional until better data are available. The mortality numbers are also small, reflecting the long natural history of prostate cancer progression even among high-risk patients, and the fact that, at modern dose levels, both the monotherapy and the combined modality may cure or delay progression for a long time.

As we’ve seen, the combined modality approach does increase the side effects of treatment. The fact that there is so far no discernable survival benefit for intermediate-risk patients should dissuade those with “favorable” intermediate risk prostate cancer from pursuing boost therapy. Each “unfavorable” intermediate-risk and high-risk patient will have to assess for himself whether the added toxicity is worthwhile.

Editorial note: This commentary was written for The “New” Prostate Cancer InfoLink by Allen Edel.


3 Responses

  1. Thank you for writing this, Allen. You might remember from a previous, closely related, post of yours, that I am a high-risk patient who received EBRT + HDR Brachy + 3 years ADT. The first two modalities were concluded in August 2009, at Uppsala University in Sweden. That post supported the use of my treatment, as does this, so I am more satisfied than before.

  2. George,

    I think it’s a great choice. How have the side effects been for you?

  3. Dear Allen,

    The side-effects are many and vary from trivial to medical emergency. I knew about some of these from my reading, but almost nothing except impotence from any doctor at the start of treatment. I dislike that and the doctors knew it. Only one showed any interest in my quite non-standard case history. (I left the Netherlands, as I explained.) That person told me after treatment that the staff were mainly worried about cardiovascular issues. I think I got the long ADT thanks to this person, who argued for it. I accepted the 3-year Zoladex treatment. I was and am mainly interested in comfortable survival. I felt I had no choice. So far so good, although I gained weight.

    Now, I am impotent, but never had much interest in sex. Fine if it was there, unimportant if not. I was more incontinent than now, 6 months ago, but fecal incontinence developed to a degree. These are “late side effects.” Again, I feel I had no choice, as I am high risk. There are gastrointestinal issues, namely diarrhea that comes and goes, partly due to diet changes I think.

    About 3 weeks ago I suddenly got acute urine retention, a medical emergency. I now think that this resulted from damage to my bladder caused by radiotherapy. I expected a urethral stricture. To keep this short, this issue was solved for now by a muscle relaxant to prostate that is designed for benign prostatic hyperplasia. This lowers blood pressure and, I think, widens small prostate muscles. That organ then exerts less pressure on my bladder. I saw this damaged prostate and urethra during a cystoscopy. It was fascinating. Coagulated blood at the main damaged area, irritation at several points.

    That is all I can say now. Cognitive effects? More another time.

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