Caveats and cautionary notes
The authors acknowledge that the study has limitations related to its methodology and underlying assumptions. For instance, some premature cancer deaths that were classified as preventable may have been averted through curative therapy as well.
The findings also represent a snapshot of premature mortality in 2020 but do not necessarily predict progress in cancer control over time.
In Dr. Chatterjee’s view, this is “an excellent descriptive study that gives a good overall picture about the potential for saving a very large fraction of premature death due to cancer by implementing what is now known about primary and secondary interventions, and treatments.”
However, estimates for the effects of various risk factors and interventions are often derived from observational nonrandomized studies, which can have various types of biases, he said.
“Additionally, availability of data, observational or randomized, are often limited from many countries in Africa, Latin America, and Asia, where the cancer burdens are increasing,” Dr. Chatterjee told this news organization. “Therefore, extrapolating evidence generated mostly from North America and European countries to other understudied settings could be problematic due to difference in background in genetics, environment, socioeconomic, and cultural differences.”
Dr. Meyerowitz-Katz said the issue with this “very complex” article is that it includes “models built upon models, all of which include layers of assumptions that aren’t always obvious and may be wrong.”
On top of that, he said, “there are questions over whether the modifiable risk factors are really modifiable. Can we really get rid of 100% of ‘lack of physical exercise’? What would that even look like?”
Overall, Dr. Meyerowitz-Katz noted, “Yes, some proportion of these cancers could be prevented, and that percentage may be large, but the exact 70% estimate is very uncertain in my opinion.”
The study had no commercial funding. The authors, Dr. Chatterjee, and Dr. Meyerowitz-Katz have disclosed no relevant financial relationships.
A version of this article first appeared on Medscape.com.