Sunday, August 04, 2013

SMA Screening - so what is it all about?

What is screening?
What does it mean?
Let's get back to basics, using language that we all understand.
Screening is the process of looking at a group of people who is thought to be at risk from a condition in an attempt to identify those more likely to have or develop the condition; in these people, some form of  treatment would be possible.
As an example, in the case of cervical screening - and as a woman I understand this! - women between the ages of 25 and 64 are invited to attend for smears.  The smear is done with the aim of identifying abnormal cells and allowing treatment to be done before cancer develops.
So, it sounds simple, yes?  Well, no, not really; apply it to a condition as complex as SMA and it becomes difficult.

OK, we know that ultimately we want to prevent a condition which causes some degree of harm to the individual, but during my training I discovered that a lot of information has to be gathered and research evaluated before screening could even be considered, with many hurdles to be crossed, loops to be negotiated and boxes to be ticked, and then the real process of working through the information, which takes time, is done.


The UK National Screening Committee have the important job of, on a very basic level (and with out explaining their role in full), approving whether a screening programme  is appropriate or not.  Their criteria is based on the Wilson Criteria (1968) which emphasises the important features of any screening program:
  • the condition should be an important health problem
  • the natural history of the condition should be understood
  • there should be a recognisable latent or early symptomatic stage
  • there should be a test that is easy to perform and interpret, acceptable, accurate, reliable, sensitive and specific
  • there should be an accepted treatment recognised for the disease
  • treatment should be more effective if started early
  • there should be a policy on who should be treated
  • diagnosis and treatment should be cost-effective
  • case-finding should be a continuous process
Personal accounts and stories of loss and hardship are not taken into account.  The committee do not see those affected; the Eilidhs, Beatrices, Estellas, Rowans, Eythans, Georges and the thousands of other children with SMA in this world.  They are not there - however much we wish they were - to lend a listening ear or to offer sympathy - although I am sure that on an individual level those involved in the decision making are empathic.  Their job is to provide the government and the NHS an impartial, scientific and cost-effective recommendation on whether screening for SMA should be offered to the general population.
SO what does the UK NSC have to say about SMA Screening?  They asked an expert and the report titled "An evaluation of carrier screening for spinal muscular atrophy against the National Screening criteria" was completed in November 2012 and brought to the public's attention recently.  What does this say?  The doctor in me will answer that question here in the next post.

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