Selasa, 16 Oktober 2012

Cancer


Mouse “avatars”: New predictors of response to chemotherapy?


Over the years, I’ve written a lot about “personalized medicine, mainly in the context of how the breakthroughs in genomic medicine and data pouring in from the Cancer Genome Atlas is providing the raw information necessary for developing truly personalized cancer therapy. The problem, of course, is analyzing it and figuring out how to apply it. Another problem, of course, is developing the necessary targeted drugs to attack the pathways that are identified as being dysregulated in cancer cells. Oh, and there’s that pesky evolution of resistance to antitumor therapies. Indeed, most recently, the Cancer Genome Atlas is bearing fruit in breast cancer (a study that I’ve been meaning to blog about).
One problem with modeling the pathways based on next generation sequencing data and expression profiling is testing whether therapies predicted to work from these analyses actually do work without actually testing potentially toxic drugs on patients. Cell culture is notoriously unreliable as a predictor. However, there is another way that’s intriguing. Unfortunately, as intriguing as it is, it has numerous problems, and, unfortunately, it’s being prematurely marketed to patients. Although I had heard of this technique as a research tool before, I learned about its marketing to patients when I came across an article by Andrew Pollack in the New York Times entitled Seeking Cures, Patients Enlist Mice Stand-Ins. Basically, it’s about a trend in science and among patients to use custom, “personalized’ mouse xenograft models in order to do “personalized” therapy: Read More
Countering ideologically motivated bad science, pseudoscience, misinformation, and lies is one of the main purposes of this blog. Specifically, we try to combat such misinformation in medicine; elsewhere Steve and I, as well as some of our other “partners in crime” combat other forms of pseudoscience. During the nearly five year existence of this blog, we’ve covered a lot of topics in medicine that tend to be prone to pseudoscience and quackery. Oddly enough, there’s one topic that we haven’t really written much about at all, and that’s genetically modified organisms (GMOs). GMOs, as you know, are proliferating, and it’s quite worth discussing the potential and risks of this new technology, just as it is worthwhile to discuss the potential benefits versus the risks of any new technology that can impact our health, not to mention the health of the planet. Unfortunately, GMOs have become a huge political issue, and, I would argue, they have become just as prone to pseudoscience, misinformation, and bad science as vaccines, with a radical group of anti-GMO activists who are as anti-science as any antivaccinationist or quack. Read More
Frightening Breast Cancer Patients with Bad Science

The issue is not just skewered science, because  the article contains information that is easily misunderstood without a proper context. Breast cancer patients are urged to take get psychosocial intervention under the threat that if they do not, they are missing an opportunity to control the progression of their disease. This is an example of the irresponsible nonsense that I have been complaining in the past two blogs. There is simply no evidence that psychological interventions can slow progression of cancer or extend life. Claims to the contrary serve to burden cancer patients with an unrealistic responsibility for the outcome of their medical condition. Patients who experience progression to a terminal condition are provided with an irrational sense that they are to blame because they did not take the right steps, namely avail themselves of effective psychological interventions. This article implies that breast cancer patients with an unfavorable course have brought it on themselves by getting too stressed out. Read More

As part of my ongoing effort to make sure that I never run out of blogging material, I subscribe to a number of quack e-mail newsletters. In fact, sometimes I think I’ve probably overdone it. Every day, I get several notices and pleas from various wretched hives of scum and quackery, such as NaturalNews.com, Mercola.com, and various antivaccine websites. I think of it as my way of keeping my finger on the pulse of the antiscience and pseudoscience wing of medicine, but I must admit that I don’t really read them all, but they do allow me to know what the quacks are selling and what new arguments they’re coming up with without actually going to each of their websites. I can then judge by the headlines and the blurbs included in the e-mails whether I think it’s worth it to go to the website itself and, of course, whether the topic might represent fodder for a good blog post. I will admit that not all the sites I monitor are as loony as the Health Ranger’s. In fact, I monitor the blogs and websites of the National Center for Complementary and Alternative Medicine (NCCAM), various naturopath organizations, and the like in order to learn of the “respectable” arguments being used to tout various nostrums. Read More

One question that comes up again and again is, “What’s the harm?” Basically, this question boils down to asking what, specifically, is the downside of choosing quackery over science-based medicine. In the case of breast cancer, the answer is: plenty. The price of foregoing effective therapy can be death; that almost goes without saying. In fact, it can be a horrific and painful death. It is, after all, cancer that we’re talking about. Aside from that, however, the question frequently comes up just how much a woman decreases her odds of survival by avoiding conventional therapy and choosing quackery. It’s actually a pretty hard question to answer. The reason is simple. It’s a very difficult topic to study because we as physicians have ethics. We can’t do a randomized trial assigning women to treatment or no treatment, treatment or quacke treatment, and then see which group lives longer and by how much. If a person can’t see how unethical that would be without my having to explain it, that person is probably beyond explanations. (As an aside, I can’t help but point out that a randomized trial of not vaccinating versus vaccinating is unethical for exactly the same reason; physicians can’t knowingly assign subjects to a group where he knows they will suffer harm. There has to be clinical equipoise.) There’s no doubt that foregoing effective treatment causes great harm. Read More


Prostate Cancer Dilemmas: To Test or Not to Test, To Cut or Not to Cut

The issue of PSA screening has been in the news lately. For instance, an article in USA Today reported the latest recommendations of the US Preventive Services Task Force (USPSTF): doctors should no longer offer the PSA screening test to healthy men, because the associated risks are greater than the benefits. The story was accurate and explained the reasons for that recommendation. The comments on the article were almost uniformly negative. Readers rejected the scientific evidence and recounted stories of how PSA screening saved their lives.
It’s not surprising that the public fails to understand the issue. It’s complicated and it’s counterintuitive. We know screening detects cancers in an early stage when they are more amenable to treatment. Common sense tells us if there is a cancer present, it’s good to know about it and treat it. Unfortunately, common sense is wrong.  Large numbers of men are being harmed by over-diagnosis and unnecessary treatment, and surgery may not offer any advantage over watchful waiting. Read More
The perils and pitfalls of “patient-driven” clinical research

Dying of cancer can be a horrible way to go, but as a cancer specialist I sometimes forget that there are diseases that are equally, if not more, horrible. One that always comes to mind is amyotropic lateral sclerosis (ALS), more commonly known as Lou Gehrig’s disease. It is a motor neuron disease whose clinical course is characterized by progressive weakness, muscle atrophy and spasticity, with ultimate progression to respiratory muscles leading to difficulty breathing and speaking (dysarthria) and to the muscles controlling swallowing. The rate of clinical course is variable, often beginning with muscle twitching in an arm or a leg or slurring of speech. Ultimately, however, ALS progresses to the loss of ability to move, speak, eat, or breathe. The most common cause of death is from respiratory failure, usually within three to five years after diagnosis, although there is the occasional outlier with a less malignant form of the disease with a slower course of progression who can live a long time, such as Steven Hawking. Read More

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