By widening access to tests that can accurately and safely
pick up cancer, the theory goes that you can then treat it at an earlier stage,
with greater chance of cure, fewer potential side effects, and less cost all
round. Everyone is a winner.
This is the premise that we at PREDICT-PD, along with many
others around the world are working towards in the ‘war on neurodegenerative
diseases’ such as Parkinson’s and Alzheimer’s diseases. Disease modifying
trials in Alzheimer’s failed to meet their primary end point and one of the
lessons that the research community is learning is that established disease may
be too late for disease modifying therapies to be effective. This is most
likely due to the irreversible buildup of the disease-causing proteins that ‘clog
up’ the brain.
One word of caution in the cancer tale, is the concept of
lead-time bias. If a person dies of cancer age 85 and the cancer is picked up
at the age of 83, they are said to have survived for 2 years. Now if their
cancer is picked up at the age of 80, but despite treatment, they still die at
the age of 85, it looks like they have survived over twice as long, yet they
haven’t lived any longer! In simple terms, it is a way to make the headlines
look better, wihtout changing the story. This is of great relevance in cancers,
especially aggressive ones, but in neurodegenerative disease, identifying the
pre-diagnostic or prodromal phase, will be vital for trialing new treatments
that do change the course of the
disease, and put off the time at which the sypmtoms of Parkinson’s or Alzheimer’s
impact on the lives of people with the condition, as well as their families.
RNR
For more information:
I think it would be a useful measure of the prodromal stage of Parkinson's if faecal and DNA samples were taken from both the diagnosed patient and immediate carers / partners. These should be repeated yearly over perhaps 10 years. Bacterial/fungal/prion/viral analyses might show a change in the undiagnosed persons in line with the PD case.
ReplyDeleteAnecdotal information suggests a prodromal period of up to 8 - 10 years is possible - carers seem sometimes to develop PD when the patient has passed away or has reached an advanced stage.
This suggests PD may be 'contagious' but only if the genetics of the acquirer are suitably matched.
Prior to this work or alongside it could be a survey of this situation arising - in my view it is a bit more common than might be expected from mere random events.