A news item this week profiles a northeast naturopath who is using thermal imaging to screen for breast cancers. This is a frightening development. The news about conflicting mammogram recommendations has women wondering what the right approach really is. The question in the new USPSTF recommendations is one of values. The science says that a lot of women in their 40s need to be screened and undergo invasive procedures to save one life. We are left to decide if that life is worth it. Or we can throw our hands in the air and start charging women for useless alternatives.
The technology being sold by the naturopath is digital infrared thermographic imaging (DITI). The idea is that by looking at the heat pattern of the breasts, we might be able to detect the increased blood flow and heat of cancers. It is not an implausible claim, and it may be worth investigation. The one legitimate clinical study published so far had some promising results, but that’s not how we develop screening procedures. There is a well-understood statistical method for evaluating diagnostic tests. In evaluating a new test, it is tested against a “gold standard” in a representative population. Various factors need to be taken into account, including the comparative costs, risks, benefits, prevalence of disease, etc. It is not just a matter of saying, “this could work! Let’s do it!”.
Launching a new screening technique before the data support it is dangerous. It may expose patients to unknown risks, and if its negative and positive predictive value are either unknown or not good, it will lead to a false sense of security as disease is missed, and lead to unnecessary procedures as benign findings are pursued.
Doctors and other “healers” who offer this sort of thing are behaving recklessly and unethically. If a practitioner does not understand the science well enough to know this, they shouldn’t be allowed to practice. If the do understand but offer it anyway, they should be punished.