ASTRO claims “Proton therapy effective prostate cancer treatment”


A media release issued yesterday by ASTRO reads as follows:

Proton therapy, a type of external beam radiation therapy, is a safe and effective treatment for prostate cancer, according to two new studies published in the January issue of the International Journal of Radiation Oncology•Biology•Physics (Red Journal), the American Society for Radiation Oncology’s (ASTRO) official scientific journal.

In the first study, researchers at the University of Florida in Jacksonville, Fla., prospectively studied 211 men with low-, intermediate-, and high-risk prostate cancer. The men were treated with proton therapy, a specialized type of external beam radiation therapy that uses protons instead of X-rays. After a two year follow-up, the research team led by Nancy Mendenhall, MD, of the University of Florida Proton Therapy Institute, reported that the treatment was effective and that the gastrointestinal and genitourinary side effects were generally minimal.

“This study is important because it will help set normal tissue guidelines in future trials,” Dr. Mendenhall, said.

In the second study, researchers from Massachusetts General Hospital in Boston, Loma Linda University Medical Center in Loma Linda, Calif., and the Radiation Therapy Oncology Group in Philadelphia performed a case-matched analysis comparing high-dose external beam radiation therapy using a combination of photons (X-rays) and protons with brachytherapy (radioactive seed implants).

Over three years, 196 patients received the external beam treatments. Their data was compared to 203 men of similar stages who received brachytherapy over the same time period. Researchers then compared the biochemical failure rates (a statistical measure of whether the cancer relapses) and determined that men who received the proton/photon therapy had the same rate of recurrence as the men who received brachytherapy.

“For men with prostate cancer, brachytherapy and external beam radiation therapy using photons and protons are both highly effective treatments with similar relapse rates,” John J. Coen, MD, a radiation oncologist at Massachusetts General Hospital in Boston, said. “Based on this data, it is our belief that men with prostate cancer can reasonably choose either treatment for localized prostate cancer based on their own concerns about quality of life without fearing they are compromising their chance for a cure.”

Red Journal Editor-in-Chief Anthony L. Zietman, MD, FASTRO, is a co-author on the second study.

Now we don’t wish to appear cynical, but

What the first study, by Mendenhall et al., appears to be telling us is that image-guided PBRT is “effective” at 2 years of follow-up — which no one in their right mind would consider to be sufficient follow-up to claim efficacy for any other form of first-line treatment of localized prostate cancer — and that significant genitourinary and gastrointestinal side effects at 2 years are relatively few (albeit they are not non-existant), which comes as no surprise at all!

What the second study, by Coen et al., seems to show is that (after exclusion of any patients with a Gleason score of 8 to 10), the combination of PBRT + photon therapy (used in the PROG 95-09 trial between 1996 and 1999) was about as good as brachytherapy (as used between 1999 and 2002, which is not really “the same time period” at all) at about 8 years of follow-up! The authors make the interesting point that, “Comparative quality-of-life and cost-effectiveness studies are warranted.” We feel pretty confident that the combination of PBRT and photon therapy is vastly more expensive than first-line brachytherapy!

The well-informed reader may wish to compare these claims with the data presented by Mohammed et al. in a paper entitled “Comparison of acute and late toxicities for three modern high-dose radiation treatment techniques for localized prostate cancer,” which is published in the same January issue of The Red Journal. In this study some 1,900 patients treated between 1992 and 2006 were followed for a median of 4.8 years, and all patients were treated with high-dose external beam radiation therapy.

What is puzzling to us is why ASTRO would make the sort of claim that it is making based on the data from these two papers. We suspect that at least some of the authors of these two papers are not exactly enthused by this media release. (Since he would have had a conflict of interest, it is possible that Dr. Zeitman, the editor of The Red Journal, didn’t even see this media release before it went out the door.) On the other hand, the conclusion of the paper by Mendenhall et al. does appear to correlate with the claims in the media release, stating “Early outcomes with image-guided proton therapy suggest high efficacy and minimal toxicity with only 1.9% Grade 3 GU symptoms and <0.5% Grade 3 GI toxicities.”

The problem, of course, is that we are still waiting for any head-to-head data, that 2-year follow-up is of minimal value in assessing effectiveness of any prostate cancer treatment, and that in the real world no one has ever been combining PBRT and EBRT for years.

5 Responses

  1. It seems to me that the most important point of the study you refer to is that the researchers did not claim proton beam therapy was superior to brachytherapy. Your eminently accurate point that there’s an all too brief span of years for this study to mean anything in the long-run may, or that part of the study did not involve a real-world treatment modality, may be besides the point in this instance.

  2. ASTRO is made up of approx. 10,000 radiation oncologists who make a living from radiotherapy.

    Patients must never forget prostate cancer treatment is a huge business and like any market it is driven by profit.

    Per ASTRO, PBRT is no better than IMRT for patient outcome; however, it is the most expensive therapy, with IMRT next. Why do you think the CyberKnife has so much opposition from all other treatment stakeholders? It has a cure rate equal to HDR brachytherapy (both use extreme hypofractionation proven to have the highest cure rate) in the 96-98% range at 5 years both with lower rates of side effects. The CyberKnife has less risk because it is a non-surgical procedure and the toxicity to surrounding structures is lower than any other therapy (per the C.R. King, MD and Alan Katz, MD studies).

    So why does ASTRO consider the CyberKnife investigational and PBRT effective when there are more published Cyberknife data suggesting a higher cure rate and lower risk of side effects than IMRT or PBRT?

    Follow the money. Radiation oncologists get paid per session. The Cyberknife is 4 or 5 sessions; IMRT is 40-45 sessions; PBRT 35-38 sessions. Prostate cancer is about 50% of the radiotherapy market. A radiation oncologist will make 30-40% less for treating a patient with the CyberKnife. Treatment with IMRT has gone from 35 days to 40 and over? What is the incentive for ASTRO to support the CyberKnife or SBRT?

    The fox is watching after the hen house. Where is the check and balance for ASTRO?

    This is one example of our dysfunctional health care system. in my opinion.

  3. Here is a link to a media report from 2008 entitled “ASTRO: Proton Radiation Fails to Impress in Prostate Cancer Study”

    Patients have to understand every modality to make a choice that they feel is in their best interest and the best interest of the surgeon or radiation oncologist.

  4. This is quite upsetting to see the promotion from ASTRO. These are both poor studies with no valid conclusions possible and the data [from the first study] are far too immature to know what they mean. Even more importantly, to say that the treatment is as good as brachytherapy makes a very strong argument against proton therapy, both in terms of the cost and inconvenience. This is just so self-serving!

  5. Hi Gerald,

    Correct, shows the economic motive of ASTRO leadership over patient quality of care .

    There is no oversight of this gorilla which plays a major role in treatment coverage by insurance companies. Sad our health care system has evolved to serve doctors over patients.

    My opinion!

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