Tuesday, October 15, 2013

The best cancer protection: live less!

Cancer is a tragic disease given the lives it takes and the way it takes them.  For many victims, the cost of treatment even if they survive, is very unpleasant.  A current BBC story documents the heavy burden cancer takes on the European population.  Of course, the story is a plea for more research on causes and treatment.  But there are subtleties here that seem nearly always to be missed, or ignored, or intentionally avoided.

The real news story!
The general tenor of such stories, of which there is a daily flood, is that if only we could do the research to get rid of this (or that) pesky disease, we would walk straight into Nirvana, perpetual bliss in the tavern of our choice.   But that's not the grim reality. The grim reality is the Grim Reaper.

Grim Reaper

A lot of medical researchers seems to forget that there is a pine box (or ceramic jar) that's just our size waiting for each one of us at the end of the road.  We're all temporary.  Life is a molecular way for blobs of reactions to produce fuel (that is, food) for other blobs.  In our case, we're likely to be on the menu at the Bacteria Café.

So this should help mold our thinking about stories like the one cited above.  And the hopeful thing, that really does have strong scientific support, is that we really do know how to avoid the vast majority of cancers.  It is so simple, that even a scientist--or even, believe it or not, a politican, could understand it.  The trouble is, the press and research community, for some inexplicable reason, don't want you to know about it.  So, strictly as a pro bono public service, we're going to use our modest blog site to tell all.

Death is the most effective cancer avoidance program
If you want to avoid the trauma of cancer, the simple preventive therapy is:  die young!

Cancer is a genetic disease at the cellular level.  A cell--a single solitary cell--that acquires an unfortunate  (for the person whose cell it is) set of genetic variants, becomes the progenitor of the tumor that eventually is diagnosed.  It is this 'transformed' cell that begins uncontrolled division, proliferating and as its cellular descendants acquire further mutational changes, can shed from the primary tumor and metastasize to other locations, where it can damage those local tissues, and so on.

Cancer predisposition can be inherited, by involving a variety of genetic variation, most of which consists of numerous mutations (changes) in DNA sequence, and probably hundreds or even thousands of sites in our genomes could, if altered by mutation in an undesirable way, contribute to this risk.   So not being born is a perfect preventive for this....except that rarely is a newborn affected by cancer.  Instead, most cancers arise when, later in life, new body-cell ('somatic') mutations arise, until some single cell acquires a carcinogenic combination of changes.

Mutations occur all during life, as cells sit there exposed to cosmic rays, chemicals, viruses, and other potential mutagens.  When a cell divides, its changes will be transmitted to the daughter cells, unless they are detected and corrected first.  This sometimes does happen, but you have lots of cells that divide lots of times during a lifetime. Most of the evidence suggests that eventually, if you live long enough, some one or more of your cells will acquire such changes that aren't corrected.

In this sense, cancer is inevitable.  In some, perhaps especially in older people, the cells aren't dividing very rapidly anyway, and transformed cells may take very long to be manifest as a tumor that threatens their lives--if they're still alive.  In other words, even then, if you live long enough, you will be destroyed by cancer.

Competing causes, and the paradox of public health policy
The same inevitability applies to many other diseases (also mentioned in the above-cited report), if not to all diseases.  It has long been clear in principle that an organism faces a variety of ways in which its biology will deteriorate with time.  Many if not most diseases have patterns of onset, predisposition, and severity that reflect our biological development, and for which harmful life-experience can accumulate to increase risk.

Risk of a given disorder generally has a characteristic age of onset pattern.  Risk for many diseases rises with increasing rapidity with age.  Cancer is one, but so are adult diabetes, heart and kidney diseases, and cognitive deterioration.  Others have onset at puberty, etc. Many can be related to known cellular processes.  Some slow down with age if those processes do.

But in the end, we face what is called competing causes.  Mathematically, if a given cause is eliminated, or its age-risk pattern tampered with by lifestyle or public health or medical changes, the relative risk of the remaining diseases increases. So, if you stay in physical shape and hence reduce your risk of heart disease or stroke, you inevitably increase your risk of something else.  You may live longer by not having an early stroke, but what you experience instead will not necessarily be preferable except by occurring at an older age.

What would a most-sane public health (and research) policy do in the light of this?  What we have now is a set of interest groups pleading for funds to eliminate some specific disease--understandable enough--but little if any policy about priorities.  Should we reduce effort against later-onset traits, and really push hard for inborn problems, childhood diseases, lifelong quality threats?  If so, should we reduce investment in cancer or Alzheimer's Disease research?

There are no obvious answers to these questions.  There's hardly anyone even asking the questions.


Jim Wood said...

Ken, I'm disappointed this post hasn't yet generated more response. The problem of competing causes of death (never mind interacting competing cause of death) is a thorny one in both epidemiology and demography. Public utterances about the virtues of reducing or eliminating single causes routinely -- and naively -- ignore this problem, and invariably end up more optimistic than they ought to. Anyone interested in public health and health policy ought to study the whole issue of competing causes very carefully.

Ken Weiss said...

Maybe the social media market is just saturated. This is but one of many inconvenient subjects that people really don't want to think about. Nobody really gains by thinking about them--especially, such issues would not feed the many interests that have their hands in the kitty at present.

With the waning of religion as a kind of moral force (if it ever had such a force), it is not easy to see how such uncomfortable real-world issues can get addressed. We see this all over the scientific and political landscape.