Challenges to studying population effects of medical treatments

Excerpt

Harbron and colleagues report on cancer among young patients who have undergone cardiac catheterizations in the UK [1]. For patients who undergo cardiac catheterizations, there is substantial value in understanding potential for increased cancer risks after the procedure. Nonetheless, cardiac catheterization is a relatively rare procedure among children and young adults and therefore the public health impact of iatrogenic cancer following such an uncommon medical procedure is unlikely to be large. Along these lines, the authors lay out one reasonable, albeit quite modest goal for their study: to assess the incidence of malignant neoplasms among young cardiac catheterization patients. This can be done fairly succinctly; Harbron et al. studied 11,270 cardiac catheterization patients among whom there were 40 people who were subsequently diagnosed with a malignant neoplasm over a mean 8.4 years of follow-up. The findings are coherent with some, but not all, prior studies and suggest a moderately higher risk of cancer overall among cardiac catheterization patients than is observed in the general population [2, 3]. …