Cancer and Cancer Diagnoses

There has been concern about an apparent rise in cancer diagnoses over the last couple of decades, some of which is appearing among younger segments of the population.  (The vax safety nuts have attempted to claim this is due  to CV-19 vax, which is complete garbage and I will deal with in a separate post.)  I have discussed in other contexts the issue of “diagnosis” and its relationship to true incidence and prevalence of a disease.  Incidence is the number of new cases in a time period, usually a year, and prevalence is the total number of people in a population with a disease at any point in time.  The underlying question is whether cancer prevalence has actually risen or whether due to better screening, etc., incidence appears to be rising due to more diagnoses.  A change in diagnoses is not the same as a change in true prevalence.

A study in the Journal of the American Medical Association suggests that the rise in cancer diagnoses among young people is in fact largely due to more screening and other factors, and is not reflective of more cancers.  It is certainly true that the age for many recommended screenings has been lowered in recent years.  For the eight cancers with the fastest rising incidence in adults 50 and under, incidence doubled since 1992, but mortality remained the same.  This could reflect better treatment, but it is more likely that it is earlier diagnosis of clinically insignificant cancers.  People have lots of cancer that never does anything serious from a clinical perspective; prostate cancer being a notable example.    (JAMA Study)

It is hard to tell what really may be going on.  I am not opposed to lots of screening, even if it identifies cancers that might not be clinically significant, causing anxiety among patients and potential overtreatment and raising costs.  When men were told not to do so much PSA screening for cancer or to do watchful waiting, we saw an increase in more serious prostate cancers.  On the other hand, the fact that we don’t see a corresponding decline in serious, metastatic cancers with increased incidence does suggest that we are just finding lots more clinically insignificant ones.  A good discussion of all these issues is found here, with a more ambivalent conclusion.  (Medscape Article)