Thursday, June 30, 2011

Why I love oncology

This applies to medicine as a whole, but in particular to oncology.  A lot of people "question my sanity" when I tell them that I want to be in a field like oncology.  "Wouldn't it be depressing to be treating cancer patients all of the time, especially when ones that you become close with ultimately have unsuccessful treatments?"

It is all about how one looks at things.  For starters, maybe cancer as a disease is a depressing thing but oncology as a specialty is amazing.  Before 1950 or so, all cancers had the same prognosis:  zero, give or take a few hundredths of a percent.  Now, we save people all of the time.  Colon cancer can be resected and cured with surgery and chemo.  Testicular cancer has a 95% survival rate when only a few decades ago it was 5%.  Many pediatric leukemias we can treat with some efficacy.  For cancers we can't cure, we can certainly make the remaining life better.  In oncology, is it isn't about who you lose - its about who you don't.  Those are the cases where, after, you can look Mother Nature in the eyes and say "we beat you."

The other thing about oncology, although this applies to other fields as well (for example, transplant surgery, which I am on right now), is the effect it has on me as a person.  Its so easy to go home at night and be tired and think, "I want to do nothing", or "I am too tired to go on a run."  Then you remember the stage IV cancer patient who is bed-ridden and beyond cure, without long to live.  Or you might remember the young guy who is stuck in the ICU.  He already had a liver transplant once to save his life, but his immune system has systematically destroyed it despite our best efforts.  Each day we see the new numbers, each day more abnormal, as the liver functions less and less. 

Remember those things and all of the sudden, you have the energy to go for a run or to go out and socialize - because you can.  Because you are so aware that someday, you won't be able to.  Think forward - many of us will be in that very position some day.  What would we give for the chance to come back and be 28 and be healthy enough to do those things?  If that time comes for me, I will smile when it does, because I will know I did.  With the right perspective, oncology is an incredibly uplifting discipline.

Wednesday, June 29, 2011

Reason as a weapon

A recent NYT article about reason summarized viewers responses as thus:

"Reason Seen More as Weapon than Path to Truth".

The NYT went on to describe the title: "a description, that implied that reason is not, as we generally think,  directed to attaining truth, but rather to winning arguments."

I recently heard a quote by some physician which has become one of my all-time favorites. Roughly, it is:  "Humans are forced to choose between truth and certainty. We can have one, or the other, but we cannot have both." 

A person who would prefer certainty over truth would definitely perceive reason to be a weapon. If such a person were interested in 'truth' in the first place, then 'certainty' would not have been their priority all along. To be interested in truth is to be interested in reason. To be interested in certainty is to be indifferent at best, or hostile at worst, to reason.

This is why so many religious people are hostile to science these days (actually the cause is more a product of manipulative religious leaders creating a false enemy to inflate their own sense of importance, but I digress). When people are told that the theory of evolution undermines their religious beliefs (it shouldn't), they are instinctively hostile to the logic and reason of the theory.  To let any of it in would be to suspend their certainty about how the world was created. 

Another interesting thing about this quote (that we can have truth or certainty but not both) is that it is reflected in the physical world by the Heisenberg Uncertainty Principle.  The principle states that we may know the position of a subatomic particle, or we may know the momentum of the particle, but we can never know both.

As for me, I always choose truth over certainty.  I am 100% certain of that.  Or am I?

Monday, June 27, 2011

On Surgery, etc.: The Part-Time Doctor

I thought this was a good read: a surgeon explains what he thinks makes a good doc. 

On Surgery, etc.: The Part-Time Doctor

Friday, June 24, 2011

Cancer in transplant patients

I meant to include this in the previous post but forgot.

Another interesting thing is that being on immune suppression drugs after having an organ transplant drastically raises the chances of developing some (but not all) cancers.  In particular, we see the sort of cancers that are a product of chronic viral infection and genomic irritation.  Squamous cell carcinomas of the skin are a big one.  Women can get these in their cervix from HPV; immune suppression makes everyone all the more vulnerable to HPV.  Other viruses, like Epstein-Barr that healthy people will clear without a problem, will fester in the body and provoke the development of lymphomas and the like.

The fact that some cancers appear in light of a weakened immune system but not others is a useful demonstration of the fact that we really don't know what causes cancer in every case.  Sometimes it seems environmental; enough radiation and anyone will get cancer; smoking cigarettes can cause lung cancer too.  Cancer can be caused by infection:  transplant patients get lymphomas and squamous cell carcinoma; AIDs patients get characteristic neoplasia (cancer) as well.  Genetic deficiency of appropriate anti-cancer genes (BRCA mutation, hereditary adenopolyposis coli, other familial cancers) can be a cause.  Maybe bad luck has something to do with it too.

Wednesday, June 22, 2011

The yin and yang of immunology

One of the tricky things about cancers is that they have figured out how to evade the police force of the body, the immune system.  The immune system should destroy cancer cells, and yet obviously it doesn't always.  How exactly cancer cells figure out how to evade the immune system is something that is being extensively studied.  The goal of cancer immunotherapy is to re-train the body's immune system to target and destroy cancer.  The best model for this is melanoma, a lethal form of skin cancer.  Right now, the best option to treat metastatic melanoma in humans is essentially to infuse patients with IL-2 (the immune equivalent of cocaine-laced red bull) and hope for the best.  With IL-2, the body's immune system changes from a local sheriff and his deputies to a full-fledged SWAT team.  The immune-swat team still isn't sure what it is hunting for, but it ends up killing a lot, including the cancer if the patient is fortunate.  (Giving the swat team specific cancerous targets is the ultimate goal.)

Transplantation immunology is precisely the opposite.  Instead of encouraging the immune system to attack the tissue in question, we are doing everything in our power to hold the immune system back.  This can be accomplished by drugs which prevent lymphocytes (immune cells) from replicating, block signaling and stimulation, or just kill the lymphocytes outright.  Obviously, if the police force is eliminated then a lot of criminals will end up running around; transplant patients are chronically dealing with infections (especially viruses like CMV, HSV, and EBV).  Despite these immune-destroying efforts, chronic rejection of transplanted organs by poorly understood mechanisms seems almost inevitable.  In humanity's defense, huge strides have been made in dealing with acute transplant rejections, which occur through better understood mechanisms.

It is really interesting if one thinks about it:  cancer cells have figured out how to avoid immune destruction, and so the answer to better transplantation immunology is potentially right in front of us and we just can't see it.  Another interesting scenario is this:  if we took a kidney from a child and transplanted it into the child's mother, the mother would reject the kidney unless appropriate immunosuppressive drugs were given (as in any other case).  How then did that child manage to survive in the mother's womb in the first place?  Why did the mother's immune system not immediately attack the fetus and destroy it?

The answer is lots of theory backed by some evidence, much of it conflicting.  This is the same state of affairs as most other things in medicine.  Humility makes a whole lot of sense. 

Monday, June 20, 2011

A way to cut everyone on the liver waiting list

Kidney transplantation, as it compares to liver transplantation, strikes me as a much lower stress affair. For starters, there are more kidneys than there are livers available for transplant (although this is somewhat negated by the fact that more people need kidneys than livers). More importantly, we can keep people alive who have no kidney function via dialysis. This affords time to search for an organ that is a really good match for the recipient. A good match minimizes immune differences (we focus on major antigens like ABO and HLA) and results in a longer lifespan of the graft (transplanted organ).

People with serious liver failure really cannot be kept alive without a transplant. The kidneys and the liver both perform a similar function: filtering toxins from the blood (among other things). Kidneys filter out substances that are ionic or polar; the liver deals with things that are not polar, or fat-soluble. Its been fairly easy for humans to develop a device that can separate ionic substances (dialysis machines) but not so easy to develop an artificial liver.

Anyhow, we can figure out in advance who will need a liver transplant and start looking for an organ for them before time runs out. The way this is accomplished is through a system (MELD) which accounts for a bunch of different factors, including some labs that assess liver and kidney function, as well as time spent waiting. The system works so that people who are closest to the end of their liver function get pushed up on the list.

One of the things that can happen with any organ transplant is a hyper-acute rejection. When this happens, the body's immune system launches an immediate attack on the new organ and the vessels end up getting clotted off and blocked. The only solution to this disaster is to remove and discard the transplanted organ. If this happens to a patient who is receiving a kidney transplant, that is bad, but at least the patient can leave and go back on dialysis. What happens if it happens to a liver transplant patient? There is no substitute.

Turns out, what happens is the patient gets moved to #1 on the national registry for livers. A new liver will be procured from somewhere in the country and delivered to the hospital within a matter of hours.

Wednesday, June 01, 2011

The Republican Yacht

I'm honestly completely baffled by the GOP's approach to trying to reform Medicare via the debt ceiling vote.  Their strategy has zero chance of working.  Even if the GOP could get it through both houses of congress, which they can't, Obama is not going to sign a bill which repeals the ACA or Medicare just like that.

So the GOP is trying this crazy strategy, which can't work, and they are going to get politically wrecked for it anyway for even trying it.  The only way this makes sense to me is if this isn't a strategy at all.  The Republican Party is like a rudderless yacht with a hundred captains all insisting it remain at full throttle despite lack of steering. 

As a continuation of a recent post about the intent of the founders, I really question whether we live in a republic anymore.  In a republic, the representatives are supposed to be principled but also pragmatic, willing to compromise to get most of what they want even if they lose some, and above all work to secure the future of the nation as a whole.  Our representatives don't do that.  They cater to every fickle inclination of their constituents and refuse to compromise on anything at all.  It really is a form of direct democracy.