This is a really difficult post to write. The word 'cancer' evokes any number of fears & unpleasant images, and I can't imagine something worse than discovering that a child has cancer. (Nor can I be certain of my own reaction, if I should find myself in that position.) But that doesn't excuse credulous reporting on the issue, most recently exemplified in this story (in the 'Life & Style' section) in the NZ Herald.
The story is about the use of plant-based compounds, called salvestrols, for children who've been diagnosed with a range of cancers. Now, a search for 'salvestrols' brings up a rather large number of websites making all sorts of claims for their efficacy, but a search for 'scholarly articles' narrows things down a bit. The first such paper to come up appears to be the one used to support the claims made by the Herald piece, & was published in the Journal of Orthomolecular Medicine in 2007. (It's worth noting that this particular field of study is not widely supported by science-based medicine and that the journal itself isn't indexed by Medline. I was intrigued to see that the editor of JOM has compared it to Medical Hypotheses, because really, that's not a good advertisement.)
Those claims include the hypothesis that salvestrols are used by our bodies to destroy cancer cells (referencing an earlier study by the same authors) and that modern practices around food-growing & preparation reduce the amount of salvestrols in our diet (with little evidence for this cited in support). Unfortunately the Herald's reporter simply presented these ideas as if they are widely-accepted facts:
they trigger a process in the body allowing it to kill diseased cells. But they have been depleted from food through modern farming and production techniques which have drastically altered diets.
The paper itself discusses case studies ie there are no controlled trials; while the case studies may suggest routes for future research they should be viewed as tentative, at best. Further, it makes the following claim:
First, it is not harmful. The toxins produced through the metabolism of Salvestrols by CYP1B1 are confined to the cancer cells and are exhausted through the destruction of the cell.
And yet GSK stopped a trial of a salvestrol (reservatrol) in cancer patients because not only was there no evidence of efficacy, there was evidence of harm (kidney damage). Hardly suprising as compounds such as reservatrol appear to have an effect on quite a range of metabolic pathways in our bodies.
Now, that information was fairly easy to find, so it was really, really disappointing to see the Herald's reporter referencing the JOM – and the British Naturopathic Journal – as being the best source of information on this subject.
It's also important to note that the people identified in the Herald story as successfully using salvestrols as a cancer treatment have also had surgery & in some cases chemotherapy as well. It's entirely possible that the medical treatments alone have resulted in patients being in remission – and without properly-designed clinical trials there's no way to identify any impact of the plant compounds. Nor is it enough to say that it's "common sense" that they work; as a colleague's said to me, blood-letting was also seen as a common-sense treatment for pretty much everything that ailed you.
This isn't the first time that we've seen such poor reporting around such a serious issue; sadly, I suspect it won't be the last.