Sunday, October 17, 2010

Sugar Baker Procedure

In clinical science, if you ever hear of something with an unusual name, chances are it has something unique about it.  Consider an appendectomy--a boring name for the removal of the appendix, or cholecystectomy--a snooze of a term to describe the removal of the gallbladder; but both names serve a purpose in that they describe the procedure.  Now consider the Sugar Baker procedure.  Based on name alone, you don't have much to go by, unless you incorrectly suspect that it has something to do with confectionery. 

In talking with someone, they mentioned the Sugar Baker procedure, and it piqued my interest to the point that I wanted to know more about it.  What did it entail?  How did it get its name?  Why did one do it?  Thus, I went to the handy-dandy tool I often use--Google Scholar.  I found some helpful articles, but nothing of particular interest.  After resigning to the fact that I needed to do a more intensive search, I found a useful article: the treatment of peritoneal mesothelioma using the Sugar Baker procedure.  Along with a type of advanced stage colon cancer, these two cancers are the primary indications for the Sugar Baker procedure.

Despite scouring sources for information on peritoneal mesothelioma, I found little to describe this rare cancer's pathogenesis.  We have long associated asbestos as the primary cause of mesothelioma, but this applies when it develops in the lungs.  To date nobody has developed a concrete pathway for the development of mesothelioma in the peritoneum--the lining of the abdomen.  At least a third of patients with peritoneal mesothelioma have no history of asbestos exposure.  Without an understanding of how asbestos could get into the peritoneum exclusively, and a detailed social history of all patients to rule out asbestos exposure, the link between asbestos and peritoneal mesothelioma remains merely a working hypothesis.

Nonetheless, as with its pulmonary counterpart, it has a grim outcome.  Being rare doesn't help, since most money goes into the research of the more common malignancies.  As with all cancers, the only potential cure revolves around the possibility of the removal of all cancer cells.  To successfully rid the body of cancer, you must either completely remove or kill all cancer cells; typically done through surgery, radiology, or chemotherapy.  Each of these methods has its limitations; not all cancers respond to chemotherapy, some parts of the body can't take radiation, and sometimes surgery just isn't feasible.  In the case of peritoneal mesothelioma, surgery is the treatment of choice--the Sugar Baker procedure; only recently did surgeons come to recognize its efficacy.

Named after the physician who first employed it, the Sugar Baker procedure takes a lot of time and will have a heavy impact on the patient's life.  Basically, you cut open the abdomen, and remove all visible cancer.  Some things cannot be removed, but things that can come out include the colon, the spleen, the gallbladder, the omentum, and the much as possible in so far as it is possible to remove the cancer.  After surgical removal of as much cancer as possible with regard to what must stay, the abdomen is then filled with heated chemotherapeutics, such as cisplatin or doxyrubicin; again, in the hopes of killing any remaining cancer. 

A 2010 study investigated the use of the Sugar Baker procedure for periteonal mesothelioma.  In looking at 20 patients, it found that in the years following the procedure, only six of the patients survived without disease recurrence.  Just over 25%, with further follow-up necessary to track the possibility of future cancer development. 

I have heard people debate the use of the Sugar Baker procedure, given its possible outcomes.  After all, living without a spleen and a colon does not come without consequence.  But then again, it gives the potential of life to someone otherwise destined for death. Tudor EC, Chua TC, Liauw W, & Morris DL (2010). Risk factors and clinicopathological study of prognostic factors in the peritoneal mesothelioma. The American surgeon, 76 (4), 400-5 PMID: 20420251

Sunday, October 10, 2010

New study out of Norway: calling mammograms into question

A new study came out of Norway and appeared in the New England Journal of Medicine recently, casting doubt on the benefit of mammograms.  It analyzed data on over 40,000 women, aged 50-69yrs, over a nine year period, and found that mammographic screening alone accounts for a modest 10% decrease in breast cancer death.

Based on these results, some naysayers may want to denounce the use of regular mammograms to help the battle against breast cancer.  But I would disagree.  As with any study, we need to consider the possibilities.

Partial list of risk factors for breast cancer

  • Genetics: BRCA-1 and BRCA-2
  • Family history
  • Age: increased risk with age
  • Obesity
  • Excessive alcohol use
  • Lack of physical exercise

This list is hardly complete, but I want to stress a point: looking at one group of women leaves open many possibilities.  
  • Do the BRCA gene mutations run in the Norwegian population?  Since it does have a prevalence in the American population, this is an important question.
  • Obesity: a very clear risk factor; America has a definite problem with obesity, does Norway?
  • Excessive alcohol use: is this prevalent in Norway?
  • Lack of physical exercise: America is not known as a very active nation, how does Norway compare?

Those four questions alone could drastically change the outcome of the study.  If the population is less likely to develop breast cancer in general, then mammograms will diagnose breast cancer less frequently.  We also have to consider the presentation of breast cancer: how do lifestyle and genetics affect the radiographic presentation of breast cancer?  This too could affect the outcome of the study.

Other studies contradict the Norwegian study, and I have to agree with the contradictions, although on different grounds.  Mammography does not expose a woman to significant levels of radiation.  What significant disadvantages exist?  

Even going by this Norwegian study: 10% more lives saved is 10% more than zero.

For the record: One study is hardly enough to change a well practiced medical routine.
Mette Kalager, M.D., Marvin Zelen, Ph.D., Fr√łydis Langmark, M.D., & Hans-Olov Adami, M.D., Ph.D. (2010). Effect of Screening Mammography on Breast-Cancer Mortality in Norway NEJM, 1203-1210

Sunday, August 1, 2010

Where to begin?

I began this blog as a means of discussing science, both old and accepted as well as new and open for question. In reality all science can be viewed as open for question.  Without questioning things rarely change, because they have no reason to.  When we accept something as fact and without question, we essentially end any discussion of an alternative.  Just as in the past, today is no exception in that we have people against this idea of questioning.  Take for instance evolution, one unnecessarily hot topic.

Evolution began as an idea originally postulated by two men: Charles Darwin and Alfred Russel Wallace.  Previously the work of a Catholic monk, Mendel, had suggested the basic mechanism of evolution.  These former two men suggested that nature selects who moves on to pass on their genes, and who does not and thus disappears.  This simplistic explanation belies the true science behind evolution, but let me try to explain it:

An offspring is born with various mutations, most of which go unnoticed throughout his lifetime.  However, sometimes the environment of that offspring changes, thus making the mutation useful.  In this instance he thus has an advantage over those around him, and therefore has a greater likelihood of passing on his genes.  Each of his offspring inherits the advantageous gene, and so on.  Overtime a population develops to survive their environment, and adapts through this genetic process to survive changes in the future.

To put an example to it: an individual is born with a mutation that affects his immune system, making it lack a certain biochemical marker.  Because the immune system has numerous pathways this individual notices no difference in health compared to others around him.  However, a new and unknown virus breaks out in the population, which requires that specific biochemical marker in which to enter cells.  Some survive by chance, but most perish.  Meanwhile this individual survives not by chance but by merit of this mutation.  He then mates and passes on this gene.  In the future when the virus reappears in the population his children will have an advantage over those without this trait, and over time their genes will come to dominate the gene pool.  Similarly other mutations will be selected for as the environment changes.  Some will select for physical characteristics, others for biochemical, and so on; surviving disease, getting food, attracting mates---these characteristics serve a purpose to increase the likelihood of survivability.  Thus with time the population evolves, adapting to its environment through changes to its gene pool.  For some species this can take as little as days, where as for others it can take hundreds of thousands of years.  Nonetheless enough research has backed this science that it has reached the level of theory, something not easily attained in the world of science.

This theory, however, has come under attack from those who wish to adhere to the Biblical story of creation. The stories of Adam & Eve romanticize the origin of humanity, promoting the belief that a deity created humans.  This group of people uses the term theory loosely, referring to their story of creation as a theory in its own right.  While it lacks the protocols requisite of a scientific theory, they insist it has as much merit as evolution.  But why?  Why does the idea of evolution create so much fear and hostility with this group?  I do not know, but to drop evolutionary science would set science back.  In fact, to disregard it outright would essentially deny any importance to genetics.

I do not wish to come off as anti-Bible.  In fact, I hold a strong belief in God.  But to understand science and to watch it grow, we need to put aside our firmly held beliefs in order to question.  This all brings me back to my original question: where to begin?  Let's begin with approaching science with a clean slate, and later justifying any realities discovered along the way.