This is a science and medicine story we have been following for a while – out of personal and scientific interest, and the need to correct confused or misleading new reporting on the topic. Are cell phones linked to an increased risk of brain cancer or other tumors? New data is reassuring.
David Gorski and I have both written on this topic. To give a quick summary, there is no convincing data to link cell phone use and brain cancer. Epidemiological studies have not found an increase in the incidence of brain cancer following the widespread adoption of cell phones in the mid 1990s – as one would expect if there were a causal relationship. Further, large scale studies have not found any consistent correlation between cell phone use and brain cancer.
It is clear from the literature that there is no measurable increased risk from short term cell phone use – less than 10 years. There is no evidence to conclude that there is a risk from long term use (> 10 years) but we do not yet have sufficient long-term data to rule out a small risk. Further, the data is somewhat ambiguous when it comes to children – still no convincing evidence of a link, but we cannot confidently rule out a link.
We know that drinking alcohol during pregnancy can cause birth defects; the government-mandated warnings on alcoholic beverage labels constantly remind us of that fact. But toxicologists remind us that the poison is in the dose: what is the dose of alcohol that causes birth defects? Heavy drinking can cause fetal alcohol syndrome, but there is no evidence that light to moderate drinking can cause it. Alcohol has been implicated in a number of other adverse effects on pregnancy and on the fetus. We simply don’t know if there is a threshold dose below which alcohol intake is safe, so the default position of most medical authorities has been to advise total abstinence during pregnancy. This is not a truly evidence-based recommendation, but rather an invocation of the precautionary principle. Those advising complete abstinence have been accused of paternalism and bias by wine-lovers and other critics, for instance here and here.
The literature on alcohol and pregnancy is extensive and confusing. It addresses many different endpoints, looking at effects on children and on the pregnancy itself. The studies are inconsistent in how they define “moderate” or “light” drinking, and they rely on self-reports that may not be accurate.
It would be impossible to read and accurately summarize such a large body of literature (over 21,000 hits on PubMed!), but here are a few examples that illustrate the scope, diversity, and conflicting results of these studies: (more…)
The road from an idea to a useful drug is a long one, and in cancer it is often particularly long. One reason is that to be able to tell whether a given treatment is effective against cancer often takes several years at a minimum, in order to determine if patients receiving the new treatment are surviving their disease longer than those who are not. Surrogate endpoints are usually not enough. Tumor shrinkage in response to a drug often does not correlate with prolongation of survival, although the converse (i.e., lack of tumor shrinkage in response to a new drug) does strongly correlate with failure of a treatment to prolong survival. In other words, effects observed on surrogate endpoints are not enough to judge whether a cancer therapy is working or not.
Three years ago, predating the existence of this blog by nearly a year, I became aware of a story that involved many of the issues in bringing a compound from the laboratory to the clinic. The case was unusual in that is is very rare to see the scientific process by which new drugs progress through the stages of cancer research, from concept to testing in cell culture to testing in animals to testing in humans challenged so strongly by patients themselves. The reason that this normally doesn’t occur is that new cancer treatments are almost always the product of either university-conducted research, pharmaceutical company-conducted research, or partnerships between the two. This case was markedly different in that it involved a chemical that was not only easy to synthesize, but cheap and long out of patent. Even more intriguing, it targeted a metabolic abnormality found in many cancer cells, an abnormality first described nearly 80 years before by Otto Warburg in 1928. This latter aspect of the drug gave it every appearance of a “rediscovery” of old wisdom that big pharma had ignored for 80 years, and that only added to its mystique.
The chemical was dichloroacetate (DCA), and three years ago it created a world-wide sensation. Last week, it created a sensation again, as breathless news reports once again overhyped its promise. Since I’ve been following the story since early 2007, I appear to be in as good a position as anyone to tell the story thus far and put the new findings into context. To begin that process, let’s head back to January 2007.
Spring is here. I don’t say that because of the warmer weather, the blooming tulips in my back yard, or the current effect of the earth’s axial tilt on the Northern hemisphere. No, in my somewhat warped world of the pediatric ICU seasons are marked by illnesses and injuries with an annual rhythm. Fall begins with a spike in cases of bronchiolitis, Summer with a near-drowning in a swimming pool. Winter has arrived when seasonal influenza reappears. And Spring, well, Spring has several harbingers, including auto vs bicycle accidents, falls from windows, and snakebites.
Sure enough, this week we admitted our first child of the year bitten by a venomous snake who, like most people unfortunate enough to be envenomated by a North American pit viper, has done very well. This child fell prey not only to our local limbless fauna, but also to one of several common myths or misunderstandings about snakebites that place the victim, rescuer, or both at higher risk for injury and complications. This post will explore some of the more common mistakes people make during North American snakebite encounters (being limited to snakes native to North America, the following does not necessarily apply to snakes from other areas).
File this post under Science-Based-You’re-Not-Helping-Please-Don’t-Do-That.
Myth #1: You Need to Know the Species / Kill the Snake
North America has around 120 species of snake, over 20 of which are venomous. With so many species, it may seem important to ID the snake so the docs in the ED can give the appropriate anti-venin. Fortunately, that isn’t the case. (more…)
Imagine you’re an FDA reviewer looking at a new drug application. Drug A relieves a symptom, but doesn’t cure any disease. It doesn’t conflict with other medications. It’s considered safe in pregnant and breastfeeding women. At normal doses, there are virtually no side effects. There’s one unfortunate problem: If you take ten times the dose, liver damage is very likely and may be fatal. In other countries, Drug A is the number one cause of acute liver failure.
Should Drug A be available without a prescription?
Now consider another drug. Drug B also treats a symptom, but can also be used to treat a number of acute and chronic conditions, some of which require monitoring by specialist physicians. Drug B should generally be avoided in children, as it is associated with a rare but fatal toxicity. Even at normal doses, it can cause an array of side effects, and severe digestive system toxicity, resulting in hospital admission, is not uncommon. It interacts with other prescription drugs, and can be fatal in overdose situations.
Should Drug B be available without a prescription?
Two recent acupuncture studies have received some media attention, both purporting to show positive effects. Both studies are also not clinical efficacy trials, so cannot be used to support any claims for efficacy for acupuncture – although that is how they are often being presented in the media.
These and other studies show the dire need for more trained science journalists, or science blogging – they only make sense when put into a proper context. No media coverage I read bothered to do this.
The first study comes out of South Korea and involves using acupuncture in a rat model of spinal cord injury. The researchers used a standard method of inducing spinal cord injury in rats, and compared various acupuncture locations to no-acupuncture control. They followed a series of metabolic outcomes, as well as the extent of spinal cord injury and functional recovery. They conclude:
Thus, our results suggest that the neuroprotection by acupuncture may be partly mediated via inhibition of inflammation and microglial activation after SCI and acupuncture can be used as a potential therapeutic tool for treating acute spinal injury in human.
The notion that acupuncture will actually improve outcome after acute spinal cord injury is, of course, extraordinary. This goes far beyond a subjective decrease in pain or some other symptomatic benefit. Therefore similarly extraordinary evidence should be required to support such a claim – and this study does not provide that.
It is my pleasure to announce the addition of a new SBM blogger. Impressed by his dedication to applying scientific principles to the profession of pharmacy, we have recruited Scott Gavura, who is currently best known for his work on Science-Based Pharmacy. You can find out a bit more about his background at his new page on SBM, and his first post is scheduled for Thursday, May 13. In the beginning he will be posting approximately once every four weeks.
Please join me in welcoming Scott to the SBM team.
For most of human history, doctors have killed their patients more often than they have saved them. An excellent new book, Taking the Medicine: A Short History of Medicine’s Beautiful Idea, and Our Difficulty Swallowing It, by Druin Burch, MD, describes medicine’s bleak past, how better ways of thinking led to modern successes, and how failure to adopt those better ways of thinking continues to impede medical progress.
The moral is not that doctors once did foolish things. The moral is that even the best of people let themselves down when they rely on untested theories and that these failures kill people and stain history. Bleeding and mercury have gone out of fashion, untested certainties and overconfidence have not.
Burch’s conversation with his rowing coach epitomizes the problem:
“I want you to keep your heart rate at 85% of max for the next hour and a half.”
“Because it’s the best way to improve your fitness.”
“How do you know?”
“Because I’ve done it before and it worked. Because that’s what the people who win the Olympics do. I know, I’ve trained some of them.”
“But has anyone actually done an experiment?”
“What on earth are you talking about?”
This book is Burch’s answer to his coach’s question. Medicine’s “beautiful idea” is that we should test all hypotheses and beliefs using the kind of tests that are reliable for determining the truth. Instead of going by tradition, authority, theory, common sense, or personal experience, we now have effective tools to find out for sure whether a treatment really works. (more…)
Mark Crislip is always a hard act to follow, particularly when he’s firing on all cylinders, as he was last Friday. Although I can sometimes match him (and, on rare occasions, even surpass him) for amusing snark, this time around I’m going to remain mostly serious because that’s what the subject matter requires. I’ve said it before and I’ll say it again: I’m a bit of an odd bird in the world of cancer in that I’m both a surgeon and I run a lab. Sadly, there just aren’t very many surgeons doing basic and translational research these days, thanks to declining NIH funding, increasing clinical burden necessitated by declining reimbursements, and the increasing complexity of laboratory-based research. That’s not to say that there aren’t some surgeons out there doing excellent laboratory research, but sometimes I feel as though I’m part of an endangered species, particularly years like this when grants are running out and I need to renew my funding or secure new funding, the consequence of failure being the dissolution of my laboratory. It’s a tough world out there in biomedical research.
As tough as biomedical research is in cancer, to my mind far tougher is research trying to tease out the relationship between environmental exposures and cancer risk. If you want complicated, that’s complicated. For one thing, obtaining epidemiological data is incredibly labor- and cost-intensive, and rarely are the data clear cut. There’s always ambiguity, not to mention numerous confounding factors that conspire to exaggerate on the one hand or hide on the other hand correlations between environmental exposures and cancer. As a result, studies are often conflicting, and making sense of the morass of often contradictory studies can tax even the most skillful scientists and epidemiologists. Communicating the science and epidemiology linking environment and cancer to the public is even harder. What the lay person often sees is that one day a study is in the news telling him that X causes cancer and then a month later another study says that X doesn’t cause cancer. Is it any wonder that people are often confused over what is and is not dangerous? Add to this a distinct inability on the part of most people, even highly educated people, to weigh small risks against one another (an inability that has led to phenomena such as the anti-vaccine movement), and the task of trying to decide what is dangerous, what is not, how policy is formulated based on this science, and how to communicate the science and the policy derived from it to the public is truly Herculean.
This is not an easy blog to write. Doctors Novella and Gorski want the entries to be formal, academic, referenced, with a minimum of snark.
For the most part I comply. But sometimes. Sometimes. It is hard, so hard, not to spiral into sarcastic diatribes over the writings that pass for information on the interwebs. How should one respond to profound ignorance and misinformation? I wish, sometimes, that I could be an irascible computer as well.
What brings on this particular bit of angst is a bit of whimsy on the Internet called “9 Questions That Stump Every Pro-Vaccine Advocate and Their Claims.” by David Mihalovic, ND. Mr. Mihalovic identifies himself as “a naturopathic medical doctor who specializes in vaccine research.” However, just where the research is published is uncertain as his name yields no publications on Pubmed. BTW. I specialize in beer research. Same credentials.