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Archive for June, 2008

Stem Cell Therapy and the Need for Transparency

Dr. Geeta Shroff is an Indian physician who is running a New Delhi clinic offering embryonic stem cell therapies for a large number of various medical conditions. The only thing these medical conditions have in common is that they are incurable. Indian law allows for the use of unproven treatments for terminal or incurable diseases. I cannot know Dr. Shroff’s intentions, but she has rejected the ethics and standards of science-based medicine and in so doing has transformed herself into a dangerous charlatan.

Embryonic Stem Cell Therapy

Embryonic Stem Cells (ESC) are controversial because of the ethical and moral consideration regarding harvesting ESC and the rights of an embryo. But that is not what makes Dr. Shroff’s treatments controversial, and not what I am going to write about here. The question, rather, is the state of the science of ESC therapy.

ESC’s are scientifically interesting because they have the potential to turn into any type of cell in the body. The hope for ESC therapy is that they can be used to replace dead or abnormal tissue in the body, something which is not now possible for many conditions. (Organ and bone marrow transplants are among the current treatments to replace failing tissue.) For example, an injured spinal cord might be repaired by using ESC’s to replace the damaged motor neurons and reestablish a connection between the brain and muscles. Atrophied muscles themselves can be repaired by having ESC’s turn into working muscle cells.

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Posted in: Clinical Trials, Medical Ethics, Science and Medicine, Science and the Media

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Diagnostic Dilemmas

Sometimes diagnosis is straightforward. If a woman has missed several periods and has a big belly with a fetal heartbeat, it’s pretty easy to diagnose pregnancy. But most of the time diagnosis is much more difficult. Alzheimer’s can’t be diagnosed for sure until the patient dies and you do an autopsy. If only we had one of those Star Trek gadgets to point at our patients and give us a quick and accurate answer! Alas! We are far from perfect. All too often, we really have no idea what’s causing a patient’s symptoms. We do a complete workup and still don’t know. What then?

We all know people who have symptoms that a series of doctors have failed to diagnose, who continue to doctor-shop, hoping to find that one doctor somewhere who will find something the others have missed. Occasionally they do; but far more often these people spend a great deal of time and money chasing a will-o’-the-wisp. Sometimes as they are searching, the illness gradually runs its course and goes away. When this happens, whatever they tried last gets the undeserved credit for the “cure.” Sometimes the symptoms persist and these searches consume their life, encourage unhealthy self-absorption, and permanently ensconce them in the “sick” role.

One of the attractions of alternative medicine is that it offers far more certainty than scientific medicine. If your scientific doctor can’t see anything on x-rays, your chiropractor can. He’ll tell you he knows exactly what’s wrong: a subluxation that he can fix. Sherry Rogers will tell you all illness is due to toxins accumulating in your cells and you must “detoxify or die.” Hulda Clark will tell you it’s all parasites that she can eliminate with her magic zapper. Robert Young says the cause of all disease is acidosis. They all have confident, precise answers. Wrong ones.

The One Cause of All Disease?

It’s really easy to figure out what’s causing a patient’s symptoms if you believe there is one simple cause for all disease. While I was writing this I got sidetracked and searched the Internet for “the one cause of all disease.” I found a lot of them, including: (more…)

Posted in: Diagnostic tests & procedures, Science and Medicine

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Early detection of cancer, part 2: Breast cancer and MRI

Note: If you haven’t already, you should read PART 1 of this two-part series. It defines several terms that I will be using in this post, and I don’t plan on explaining them again, given that they were explained in detail in Part 1. Of course, if you’re a medical professional and already know what lead time bias, length bias, and stage migration are, then it goes without saying that you should still read Part 1 for its scintillating prose.

ResearchBlogging.orgWhen last I left this topic three weeks ago, I had discussed why detecting cancer at ever-earlier stages and ever-smaller sizes is not necessarily an unalloyed good. At that time, I discussed in detail a landmark commentary in the New England Journal of Medicine entitled, Advances in Diagnostic Imaging and Overestimations of Disease Prevalence and the Benefits of Therapy. The article, although nearly 15 years old, rings just as true today in its cautioning doctors about whether ever-increasing diagnostic sensitivity that imaging technology and new blood tests were (and are) providing was actually helping patients as much as we thought it was. Before we dive into this problem as applied to breast cancer, let’s review what Drs. Black and Welch had to say about screening tests for breast cancer 15 years ago, as way of background and linking my last post and this one:

Before the widespread use of mammography, most breast cancers were discovered on physical examination, as palpable lumps. In one of the few studies to assess directly the accuracy of physical examination in screening for breast cancer, only 27 percent of tumors more than 1.0 cm in diameter and 10 percent of those less than 1.0 cm in diameter were detected by physical examination. However, the mean size of breast cancers detected by state-of-the-art screening mammography is about 1.0 cm, and many of the cancers detected as microcalcifications are only a few millimeters in size.

Again, prevalence depends on the degree of scrutiny. According to the Connecticut Tumor Registry, clinically apparent breast cancer afflicts about 1 percent of all women between the ages of 40 and 50 years. In a recent medicolegal autopsy study, however, small foci of breast cancer were found in 39 percent of women in this age group. Most cancers were in the form of ductal carcinoma in situ. Furthermore, over 45 percent of the women with cancer had two or more lesions, and over 40 percent had bilateral lesions. Although it has been argued that such small in situ lesions are not detected by and are therefore irrelevant to screening mammography, about half the lesions in that study were detected, usually as microcalcifications, on postmortem plain-film radiography of the resected breasts. Because of continual technical improvements and increasingly broad criteria for the interpretation of mammograms, the detection threshold for breast cancer has fallen considerably since the time of the Breast Cancer Screening Project of the Health Insurance Plan of Greater New York (1963 to 1975). This can explain the increased prevalence of cancer on mammographic screening, from 2.717 to 7.614 per 1000 examinations (with the incidence increasing from 1.517 to 3.214 per 1000 examinations). The lower detection threshold can also explain the increase in the percentage of carcinomas in situ (stage 0) among all mammographically detected cancers — from 12.7 percent to over 30 percent. The principal indication for biopsy has changed from suspicious mass to suspicious microcalcifications. This can explain why the reported incidence of breast cancer has increased and why most of the increase is in smaller lesions, particularly ductal carcinoma in situ.

About a year ago, three major articles hit the medical press that made me start thinking about this more than I had in the past. It’s my job, after all, because breast cancer surgery is a large part of my practice, and I do breast cancer lab-based research. What also tweaked me not to put off doing part 2 of this series is that, just two days ago, there was an abstract presented at the American Society of Clinical Oncology Meeting (where I still am today) that also serves to highlight just how difficult this question of integrating a test as sensitive as MRI into a screening regimen for and preoperative evaluation of breast cancer is and how MRI should fit into in this regimen can be.
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Posted in: Clinical Trials, Public Health, Science and Medicine, Science and the Media, Surgical Procedures

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