The abstract and the media report don’t quite “synch”

A report published by Reuters within the past couple of hours makes some surprisingly assertive claims about the safety of (unspecified forms of) “radiation therapy” in the treatment of prostate cancer. These claims are all the worse for being based on retrospective analysis as opposed to any sort of prospective clinical trial.

According to the Reuters report, which is supposedly based on an article by Alibhai et al. in the journal Cancer:

  • Less than 7 percent of men with prostate cancer who have radiation therapy experience major complications in the first 30 days.
  • Among the 7,661 men who received radiation, 9 (0.1 percent) died within 30 days.
  • The 30-day mortality rate increased with age (from 0 percent for men younger than 60 years to 0.8 percent for men aged 80 years and older).
  • Only 6.5 percent of men had at least one complication within 30 days of radiation.
  • Complication rates peaked within 30 days and then declined promptly, for every category of complications.

The actual abstract of this paper states that the 7,661 patients were all treated between 1990 and 1999. Given this fact, it seems likely that the patients were nearly all treated with outdated forms of external beam radiation therapy (EBRT), and not with current forms of EBRT or brachytherapy.

Furthermore, the abstract of the paper in Cancer (but not the Reuters report) states that “A comprehensive list of 7 categories of complications was developed by combining published lists from radical prostatectomy series with input from experts.” This would seem to suggest that the study was looking solely for complications following radiation therapy that would be expected in surgical patients! What happened to short-term complications known to occur following radiation but not observed in surgical patients?

In 2005, in a report which is referred to in the Reuters article, the lead author of the present study, Shabbir M. H. Alibhai, from University Health Network, Toronto, Ontario, Canada, had originally published data stating that:

  • Among 11,010 men who had radical surgery for prostate cancer, 53 (0.5 percent) died within 30 days.
  • 30.2 percent of surgery patients had at least one complication within 30 days of surgery.

These patients were also all treated between 1990 and 1999. However, the authors later corrected the complication data in the abstract of this study to state that only 19.9 percent of the surgical patients (2,195/11,010) had a complication that needed hospitalization within 30 days post surgery.

It appears that Dr. Alibhai and his colleagues then took the odd step of comparing the two sets of data from the two separate studies, which is hardly a case of comparing apples to apples, to make the claim that radiation is “safer” at 30 days post treatment than surgery is. And somehow, in today’s Reuter’s report, a complication rate of 30.2 percent post-surgery is again being quoted by Dr. Alibhai, which would seem to contradict the correction clearly indicated in the abstract of his previous paper!

Dr. Alibhai is quoted by Reuters today as stating, that radiation “is quite safe for older patients, although it is associated with a small but measurable increase in short-term major complications.” But in a media release in 2007, Dr Alibhai was quoted as follows: “Surgery for prostate cancer can be safe and worthwhile for older men above the traditional cutoff age of 70.” The conclusion of the 2005 surgical study clearly states that, “The risk of postoperative mortality after radical prostatectomy is relatively low for otherwise healthy older men up to age 79.”

The “New” Prostate Cancer InfoLink can only state that it is aware of no surgeons who would consider surgery to be a reasonable option for a 79-year-old patient with localized prostate cancer today except under the most exceptional circumstances.

What does Dr. Alibhai actually believe? It seems to us that he is more interested in publicity for his data (regardless of what it may show) than he is in providing helpful and accurate guidance for patients (or their doctors). At least one other discrepancy between the Reuters report and what is actually stated in the abstract to Dr. Alibhai’s paper in Cancer is notable, quite apart from the discrepancies between the Reuters report and Dr. Alibai’s previously published data:

  • The Reuters report states that, ‘Alibhai and colleagues compared major 30-day complications in men who had radiation therapy or radical prostatectomy (removal of the prostate) for early “organ-confined” prostate cancer.’
  • The actual abstract as published in Cancer states, in contrast, that “the authors identified all men with nonmetastatic prostate cancer who received RT between 1990 and 1999 in Ontario, Canada. Patients who underwent a prior prostate-directed surgery were excluded.”

The two patient groups described by these definitions are very different, because the latter includes any patient with cancer that shows no actual signs of metastasis on a bone scan.

It may well be that 30-day complications requiring hospitalization following surgery for localized disease in the 1990s were more common that 30-day complications requiring hospitalization following radiation for local and regional disease. They may, indeed, be more common today too. However, if Dr. Alibhai is interested in providing useful information for patients and their physicians, we suggest that he conducts a prospective, multicenter, comparative study of such complications in patients receiving treatment today.

The “New” Prostate Cancer InfoLink does not wish to suggest or imply that we believe that surgery is any safer than radiotherapy. We are only commenting on what appears to us to be unreliable science, and we would politely suggest to the University Health Network, Toronto, that Dr. Alibhai’s statements to the media may need some careful monitoring.

We would further note that we were similarly critical of another report issued in November last year that implied that radiation therapy placed patients at a particularly high (absolute) risk for bladder and rectal cancers, without taking any account of the normal (relative) risk for these cancers in the general population.

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