In this post, I will be discussing the misguided notion that laetrile (aka amygdalin or, misleadingly, “vitamin B17″) acts as an effective therapy against cancer, with particular attention to the website “World Without Cancer“. This is not because it’s been in the news recently, but because of this site’s “Google positioning”, so to speak: googling “nontoxic.org.uk” brings up the World Without Cancer website as one of the top results. Hence, I see it as something of a duty to use this position wisely, and to demonstrate why some of the wild (yet at first glance convincing) claims made on the site are unjustified. It is also the first post on this blog in which I attempt to address the thorny issue of religion, where I feel my opinions are very different to a large proportion of the pseudoscience-debunking blogging community.
First of all, however, the World Without Cancer site.
“World Without Cancer” takes its name from a book by G. Edward Griffin which rather fancifully claims that “laetrile suppression” is part of a major conspiracy from a number of groups with financial interests in drug-related research. The book appears on Quackwatch’s list of nonrecommended books for cancer patients who may be considering alternative treatments. The site makes similar claims, that laetrile was hailed by “many” as a control for all cancers, and that:
[the] pharmaceutical multinationals, unable to patent or claim exclusive rights to the vitamin [laetrile], launched a propaganda attack of unprecedented viciousness against B-17 [laetrile], despite the fact that hard proof of its efficiency in controlling all forms of cancer surrounds us in overwhelming abundance.
Laetrile is a synthetic compound made from amygdalin, itself an extract from almonds or apricot stones. However, despite the fact that the two are distinct chemical compounds, the names are frequently confounded. Further confusion arises by the fact that Ernest T. Krebs, who “discovered” the compound, arbitrarily named it as “vitamin B17″, despite the fact that laetrile is not a vitamin. It is, however, marketed as a vitamin to give it a false sense of legitimacy.
Much is made on the World Without Cancer website of the “overwhelming abundance” of “hard proof” of laetrile’s “efficiency of controlling all forms of cancer”. In a nutshell (boom boom), the mechanism by which this “control” (a very ambiguous term which appears repeatedly to imply “cure”, an implication which the hard-to-find small-print denies) is alleged to work (on this page) appears to be as follows: the compound amygdalin can be decomposed into cyanide, benzaldehyde and glucose; this decomposition only takes place with the presence of a particular enzyme (betaglucosidase); this enzyme is only found in cancer cells; thus, voilà, the poisons cyanide and benzaldehyde only attack the cancer cells and not benign cells from body organs. Abracadabra. It is also claimed (on another page) that our “normal cells” (but not cancerous cells) contain an enzyme called Rhodanese, which allegedly “neutralises” the amygdalin, preventing it from releasing cyanide. How convenient.
If this claim is true (or at least, justifiable), then we should now be able to turn to the references and examine the “overwhelming abundance” of “hard proof” of this effect. Of course, because this is a scientific claim, these references should be presented clearly so that they are easy to follow, refer to peer-reviewed research that can be found in academic library collections, and be an accurate representation of the wider body of scientific research. Sadly, this practice appears not to have been followed. Here, out of an overwhelming list of 79 references, are the first 15:
- Clinical Oncology for Medical Students and Physicians, op. cit, pp.32 , 34
- Spontaneous Regression of Cancer: “The Metabolic Triumph of the Host!”, op. cit.,pp. 136, 137.
- Manner, HW, Michaelson, TL, and DiSanti, SJ. “Enzymatic Analysis of Normal and Malignant Tissues.” Presented at the Illinois State Academy of Science, April 1978. Also, Manner, HW, Michaelson, TL, and DiSanti, SJ, “Amygdalin, Vitamin A and Enzymes Induced Regression of Murine Mammary Adenocarcinomas”, Journal of Manipulative and Physiological Therapeutics, Vol 1, No. 4, December 1978. 200 East Roosevelt Road, Lombard, IL 60148 USA
- Vitamin B15 (Pangamic Acid); Properties, Functions, and Use. (Moscow: Science Publishing House, 1965), translated and reprinted by McNaughton Foundation, Sausalito, Calif.
- Catalona, et al. Medical World News, 6/23/72, pg 82M California cancer Advisory council, 1963, pg 10 Weilerstein, R. W., ACS Volunteer, 19, #1, 1973
- Burger, Hospital Practice, July, 1973, 55-62
- Currie & Bagshawe, Lancet, 1, (7492), 708, 1967
- Abercrombie, Ca. Res. 22, 525, 1962
- Cormack, Ca. Res. 30, (5), 1459, 1970
- catalona, et al. Medical World News, 6/23/72, pg 82M
- Jose, Nut. Today, March, 1973, pgs 4-9
- Burk & Winzler, VITAMINS AND HORMONES, vol. II, 1944
- Adcock et al, Science, 181, 8/31/73, 845-47
- Dr. Dean Burk formerly chief of cytochemistry, The National cancer institute, and Dr. John Yiamouyiannis, Science Director of The National Health Federation, Formerly an editor of chemical Abstracts.
- Fairley, Brit. Med. J. 2,1969, 467-473
Just about everything is wrong here. The remaining 64 are not much better. None of the 79 references date from conference paper third on the list, i.e. 1978. Very few of these references are full – in many cases the titles are missing. In some cases, like the first two, the dates are missing. In a number of cases, this makes finding the reference either a complete pain in the ass or a totally impossible task. Something tells me that this is not done by accident. Correct referencing is, in fact, surprisingly simple, particularly in this day and age with free, open-source reference managers such as BibTeX, Zotero and CiteULike. Zotero, in particular, is a fantastic software project which I recommend to all researchers wholeheartedly. There really is no excuse for incomplete referencing these days.
Let’s start at the beginning, with the two undated references. Both of these contain the abbreviation “op. cit.”. I admit I had to look up what this meant:
Op. cit. (Latin, short for “opus citatum”/”opere citato”, meaning “the work cited/from the cited work”) is the term used to provide an endnote or footnote citation to refer the reader to an earlier citation. To find the Op. cit. source, one has to look at the previous footnotes or general references section to find the relevant author.
Wait, what? What previous citation? These two are top of the list!
The second reference contains another error: it is misquoted. The actual, full citation is this:
Cole, W.H., 1974. Spontaneous Regression Of Cancer: The Metabolic Triumph Of The Host? Annals of the New York Academy of Sciences, 230(Paraneoplastic Syndromes), 111-141.
The subtle change of a question mark to an exclamation mark completely changes the title’s meaning. Don’t believe me? Try reading “Sorry!” and “Sorry?” out loud and see for yourself. In fact, just for fun, while you’re at it, try reading “O Watana Siam” out loud as well. Particularly if you’re reading this in a library or a busy internet café.
Reference number three refers in fact to two conference papers presented by Harold W. Manner and colleagues in the 70′s. These papers are not readily available. However, much of Manner’s work has been widely debunked by the American Cancer Society. Manner operated (or maybe still operates) a clinic in Mexico offering courses of laetrile therapy at extortionate cost. Conflict of interests, perhaps?
The fourth reference cites literature on another bogus “vitamin”: pangamic acid. Quite what its relevance is to laetrile is anyone’s guess. In any case, the lack of evidence supporting the medicinal value of pangamic acid is discussed here.
The fifth reference is, again, an untidy mish-mash, this time of three articles. One of them is in fact repeated later in the list (the tenth reference). None of the three articles could be easily sourced.
I could go on, but even going through these 15 references would be a pointless slog, not least because none of them is complete. Even finding the ones that are readily available is difficult and requires some extensive detective work. I would like to hope that this is just unintentional sloppiness, though I doubt it. Making the references as difficult as possible to check, whilst still retaining a sense of “sciency-ness” about their sheer number, is a very deliberate ploy. If this is a false allegation, then I challenge the authors to tidy up their references, after which I will retract that statement.
A couple of more recent papers regarding the efficacy of laetrile have emerged. The first, published in 2007, contains a systematic review of all the published data related to “the effectiveness or safety of laetrile interventions as a treatment of any type of cancer”. The study included articles sourced not only from “conventional” medical literature databases such as PubMed and Medline, but also from alternative medicine publication databases. Thirty-six studies were included. No controlled clinical trials were found. The authors concluded (unsurprisingly) that “the claim that laetrile has anticancer effects is, therefore, not supported by data from controlled clinical trials”. The authors also noted that a number of apparently positive results had been reported, however “all positive results came from case reports and case series where subjective responses could erroneously be interpreted as objective evidence of efficacy”. This paragraph from the discussion describes the biases inherent in these studies beautifully:
There are several reasons why the few allegedly positive results may, in fact, be ‘false positives’. In particular, one should question whether patients actually had cancer to
start with, whether the alleged benefit was due to laetrile or to concomitant treatments, and whether the outcome was real or assumed. None of the “positive” cases have been reported in sufficient detail to be sure on all these accounts. Furthermore, some of them were reported by authors who one might suspect of a conflict of interest.
The paper even mentions that the proposed mechanism of magic enzymes conveniently appearing in the right places may be (surprise, surprise) mythical. There is “no experimental evidence to show that malignant and healthy cells differ in rhodanese enzymes [citation] nor that betaglucosidase is contained in tumor tissues [citation].” In other words, the neutralising enzyme appears not only in your body cells but also in the cancer cells to a more or less equal extent, and the enzyme that releases the cyanide from amygdalin isn’t in the cancer cells at all. Whoops.
The second, published in January this year, is from the “Internet Journal of Alternative Medicine”. The paper claims that evidence on laetrile is mixed between supportive and unsupportive, and that there is evidence suggesting that “condemnation of laetrile may have been premature”. The author is Stephen D. Krashen, emeritus professor at the University of Southern California’s… School of Education. His expertise is in the field of linguistics and second language acquisition. Not, as one might assume from the paper alone, in medicine or public health.
Still, credentials are often misleading; what’s important is whether the data are unbiased, the methods are rigorous and the analysis is sound. Unfortunately, this is not the case. The first part of the paper looks at how different “studies” have categorised cancer cases and “positive responses from laetrile” as reported in a single paper (this one). Krashen identifies nine studies:
The first five entries are from refereed journals, the sixth (NCI) is a website, the seventh is a report from the US Congress, and the eighth and ninth are books.
Ah yes, “books”, those reliable, peer-reviewed sources of informed, unbiased, unopinionated study. “Books”, where one can safely assume no competing interests at all. Give me strength. Unsurprisingly, the “books” show the most favourable categorisation of the results. It is even more unsurprising to learn that one of the books is the World Without Cancer Book mentioned above. The other one, “The Cancer Industry” is written by Ralph Moss, who sells “Cancer Reports” for $297 a pop (so has a financial interest embedded in confusing people about cancer). His site is full of the usual canards, testimonials from customers and “experts”, numerous mentions of CAM, use of the letters PhD to bolster credentials, and so on. Quackwatch has a good, concise review of the book.
Krashen’s grasp of statistical methods is as poor as his regard for bias within his sources. Oddly, he begins by stating that statistical analysis was not suitable “because of the selection process used”. He then proceeds to conduct a statistical analysis. Eh?
The analysis compares data for the laetrile-treatment group with the no-treatment group. Quite why one would choose to do that is anyone’s guess, since Ellison’s report contained data on cases treated with chemotherapy. It is not sufficient only to show that a new treatment is better than nothing; it has to be shown to be better than the best currently available treatment.
The analysis proceeds rather curiously by whittling away the total number of cases in the laetrile-treatment group until the data finally showed a “statistically significant” result. The basis for this is that some of the results were inconclusive or represented “stable disease”. Funnily enough, the Krashen is not so scrupulous with the comparison group. Furthermore, Krashen presents results from both one-tailed and two-tailed tests, implying that his hypothesis is not clearly set out before commencing his analysis. He then has the gall to state that because he didn’t then go all the way and include the questionable positive cases as categorised by Moss and Griffin, that his analysis was “conservative”.
So, in summary, Krashen bases his argument on a statistical analysis where there is no clear hypothesis, a dodgy comparison group and arbitrary disposal of negative results, and these are considered conservative because they don’t diagnose positive and negative cases according to the most biased categorisation criteria he could find. Instead, it appears, he chose the second or third most biased categorisation. Still not exactly neutral then. As the final nail in the coffin, Krashen’s closing statement spectacularly misses the point of evidence-based medicine:
Clearly, Laetrile is considered guilty until it is proven innocent.
Sigh. Try “considered useless until it is proven effective” and then you might be closer to the mark.
So anyway, back to World Without Cancer. There is no evidence that laetrile is effective in controlling cancer, despite the fanciful claims. What’s particularly galling – and here’s the religion bit – is the sporadic interspertion of Bible verses around the site. As those of you who have seen my about page will know, I am a Christian, and openly subscribe to the teachings of Jesus, and use the concept of “God” to frame my understanding of the world. I make no apology for my own beliefs, and use them to underpin a lot of my scientific understanding. For me, God represents “all knowledge”, and “seeking to be more like God” is another way of saying “furthering my scientific understanding”. I don’t subscribe to the increasingly fashionable view that religion and science are diametrically opposed combatives in an eternal war against each other. I do agree with many skeptics that there are a lot of (pseudo-)religious nutcases spouting utter nonsense out there, claiming to offer religious or spiritual guidance. I do not, however, conclude that this means that religion as a whole is a nonsensical waste of time which is by definition dangerous. In a similar vein, there are a number of pseudo-scientists spouting equally despicable nonsense, claiming to offer the next new miracle cure. The difference, in my view, is that practitioners of good scientific study are active and vocal in their debunking of pseudo-science, yet those for whom religious activity is a positive thing (through cultural identification, pastoral care of the isolated and vulnerable, provision of a regular community focal point enhancing social cohesion, and so on) have unfortunately chosen to largely turn a blind eye to the nonsense and the bigotry and thus allow it to hijack the concept of “religion” and thus the public perception of it. Jesus, the story goes, was highly active in debunking the corrupt and nonsensical religious establishments of the time. I see it as my duty to debunk pseudo-science such as World Without Cancer, and at the same time, when I see it accompanied by pseudo-theology such as the following:
“These are the things you are to do: Speak the truth to each other, and render true and sound judgement in your courts.” (Zechariah 8:16)
“Each of you must put off falsehood and speak truthfully to his neighbor, for we are all members of one body.” (Ephesians 4:25)
“Then you will know the truth, and the truth will set you free.” (John 8:32)
it upsets me on two fronts. This sort of pseudo-theology suffers from similar canardery to bad science: cherry-picking (of Bible verses, rather than scientific studies), misrepresentation, over-extrapolation, taking things out of context, and so on. The Bible verses they cite speak of “truth” but alas, there is none to be found. In fact, in this post I aim to have done exactly what those verses instruct.
I hope to return to this theme in future blog posts, that holding spiritual beliefs does not automatically mean you have to be completely incapable of scientific thinking. For now, though, I wish to reiterate the point of this post: the quack miracle cures promoted by World Without Cancer are falsehoods and are more likely to relieve you of your money than your cancer. I hope that discussion will focus on this.