Results of a randomized trial of two modern types of radiation therapy

A newly published Italian study offers what we believe to be the first direct comparison of two “modern” types of external beam radiation therapy for the treatment of localized, high-risk prostate cancer. This is a relatively small trial, with relatively brief follow-up to date, but the results are nontheless interesting and important.

Archangeli et al. set out to compare the effectiveness and the side effects of of hypofractionated  vs. conventional fractionation radiotherapy in patients with high-risk prostate cancer. Between January 2003 and December 2007, they enrolled 168 patients who were randomized to receive one of the two types of radiation as follows:

  • The “hypofractionated” group received 62 Gy in 20 fractions over a period of 5 weeks (i.e., 4 treatments per week).
  • The “conventional” group received three-dimensional conformal radiotherapy received 80 Gy in 40 fractions over 8 weeks (i.e., 5 treatments per week)

The study included a number of “very high risk” patients, i.e., patients with a pretreatment PSA level >20 ng/ml, or a Gleason score of  ≥ 8 or a clinical stage of T2c or higher. These patients were also randomized between the two different treatment types.

Radiation was given to the prostate and to seminal vesicles in alol cases. In addition, all patients received a 9-month course of combined androgen deprivation (an LHRH agonist and an antiandrogen), and radiotherapy was started 2 months after the hormone therapy was completed.

The resulst of this study are reported as follows:

  • The median follow-up period was 32 months (range, 8-66 months) for the hypofractionated group and 35 months (range, 7-64 months) for the conventional group.
  • There was no evident difference in long-term (“late”) toxicity between the two treatment groups.
    • The 3-year rates of Grade 2 gastrointenstinal side effects were 17 percent in the hypofractionated group and 16 percent in the conventional group.
    • The 3-year rates of Grade 2 genitourinary side effects were 14 percent in the hypofractionated group and 11 percent in the conventional group.
  • The 3-year rate of freedom from biochemical failure (FFBF) was 87 percent in the hypofractioned group and 79 percent in the conventional group, and this difference is statistically significant.
  • The 3-year rates of FFBF in the patients at a very high risk  were 88 in the hypofractioned group and 76 percent in the conventional group, and this difference is also statistically significant. 

As the authors report, their data certainly seems to confirm that the hypofractionated radiation schedule used in this trial is superior to the conventional schedule used in this trial with respect to 3-year FFBF, andd that there was no significant difference between the two patient groups in terms of radiation toxicity. The “New” Prostate Cancer InfoLink suspects that this will be just the first in a series of trials designed to report on the relative merits of the many newer forms of radiation therapy.

2 Responses

  1. I think there was a paper presented at ASTRO in November covering a similar study(?)

    But this also shows the importance of understanding terms. At first read, I assumed that the term “hypofractionated” might refer to a very large difference in the time/dosage continuum, but this is not really the case here, unlike the use of “hypofractionated” when applied to the CyberKnife® procedure, which sees a very much larger dose (can’t recall how large and most Cyberknife sites are a bit coy on the subject), but since the total dose is given over five DAYS, not five WEEKS, it must be very much higher.

    Hopefully men considering Cyberknife — or the other very high dose hypofractionated procedures on offer — understand that studies like this and the ASTRO study do not neccessarily apply to the very short-term procedures.

  2. Terry is correct. The paper referred to in this article is the formal publication of data presented at the ASTRO meeting in Chicago on November 4. For a report on that paper at the time of it’s presentation, please see either Science Daily or the earlier report on The “New” Prostate Cancer InfoLink. The publication of the report by Arcangeli and colleagues allows for a more detailed look at the complete results of the study (for those who have access to the journal in which it is published).

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