Reblogged with permission from slippdigby.wordpress.com
Lynne McTaggart recently published another blog post titled ‘Medical McCarthyism‘ defending the content of What Doctors Don’t Tell You. In the post she attacks Cancer Research UK:-
“According to Cancer Research UK, just over half of cancer patients survive beyond five years. This is the very attractive figure now being bandied about to convince us all that we’re winning the war on cancer.”
If you look at Cancer Research UK webpage you will find survival statistics and yes, the predicted overall five-year survival figures for those diagnosed with cancer in 2007 is 46% of men and 56% of women.
Despite these figures, Lynne goes on to quote some figures which she believes supports her case that conventional treatments are actually failing:-
“Actually, as WDDTY has reported, after cherrypicking the very best clinical trials showing positive results, Australia’s leading oncologists found that chemotherapy’s contribution to five-year survival was only 2.3 per cent in Australia and 2.1 per cent in the US (Ann Oncol, 2013; doi: 10: 1093/annonc/mds636).”
These claims were featured in What Doctors Don’t Tell You Volume 23 no 11.
Now ignoring the fact that chemotherapy is only one of a range of conventional treatments, this is quite a broad, unqualified statement which would give a lay person the impression that chemotherapy is very ineffective against ‘cancer’ full stop.
Cancer is however a complex range of diseases which respond differently to chemotherapy, so I was very curious where Lynne got these figures from – it turns out the reference quoted is a paper titled Bias in reporting of end points of efficacy and toxicity in randomized, clinical trials for women with breast cancer.
Now, I am not an expert on cancer and I couldn’t get access to the full paper, but just from the abstract it seems pretty clear to me that the paper cannot possibly support a broad statement about the overall efficacy, or failure of chemotherapy. I suspected that the paper Lynne meant to refer to was The contribution of cytotoxic chemotherapy to 5-year survival in adult malignancies which is deconstructed brilliantly by David Gorski here.
So I asked Lynne if this reference was a mistake on her blog. I got no response, which is worrying as the veracity of these claims and the evidence to support them – even in a blog post – is important. Lynne has also recently defended herself by claimed that she simply reports the finding of research without bias to allow people to make up their own mind.
I thought the best way to clear this up would be to contact the lead author of the original paper Lynne cited and ask him whether the quote above regarding his paper was accurate. He was kind enough to email me and his response I reproduce below, without further comment:
I think the statement is probably accurate but quite misleading to patients. Across all cancers, I suspect the contribution of chemotherapy to long-term survival is quite low, given the prevalence of disease in the elderly and those never treated because of comorbidity, and the prevalence of minimally responsive common tumours (pancreas, lung, colon etc) where there will be little impact on 5yr survival.
However adjuvant chemo for breast and other cancers can have a substantial effect to improve long-term survival and there are many less common types (testis, lymphoma, leukemia, childhood cancers) where the effects are large.
It would be a tragedy if a young or middle-aged woman with breast cancer or a man with metastatic testis cancer refused chemo because they believed there was only a 2% increase in long term survival.
With kind regards,
Ian F. Tannock MD, PhD, DSc
Professor of Medical Oncology,
Princess Margaret Hospital and University of Toronto
Why don’t doctors tell you that the success rate of chemotherapy is 2.3%?
Because it’s not true.