Via: The Skeptic

By: Dr. Alice Howarth

Recently, across Europe we have seen a rise in alternative health practitioners promoting thermographic imaging as an alternative to conventional cancer screening techniques such as X-rays and mammograms. 

Dr Alice Howarth, a PhD cancer researcher from the University of Liverpool and the Vice President of the Merseyside Skeptics Society explains what thermography is, and whether the claims made for its effectiveness are backed up by evidence.

What is thermographic imaging?

Thermographic imaging is the detection of “hot spots” using infrared thermographic technology. Infrared is emitted by all objects that are above absolute zero (-273°C) in temperature. Thermography cameras detect the intensity of that radiation in order to identify variations in heat. They are used to detect the bodies of humans and animals at night by the military and wildlife researchers. 

Thermography has been applied in the detection of cancer since the late 1950s when it was first proposed to detect breast cancer. 

What is the mechanism for thermography in cancer?

 When a tumour grows in the body, it requires a supply of nutrients in order for the tumour to survive and grow. In order to bring oxygen and nutrients inside the tumour, the tumour generates its own blood vessels. This process creates heat; therefore, it has been suggested that “active” (growing) tumours can be detected as “hot spots” in the body using thermal imaging. 

Does thermography work?

Thermography can detect heat. Tumours are sometimes warmer than the surrounding tissue. Therefore, sometimes thermography can detect a tumour. However, thermography cannot say that a “hot spot” is hot because it is cancer. Nor can it detect a tumour that is not hot. So in many cases thermography will “diagnose” a cancer that isn’t really cancer – this is called a false positive. Thermography can also frequently miss the detection of a cancer – this is called a false negative. It is for this reason that thermography is not recommended as an adequate test for cancer. 

False positives and false negatives are so common with thermography, that many medical experts and bodies do not recommend them for use in isolation when detecting cancer. The UK’s National Health Service do not provide thermography for the detection of cancer. 

In 2017 the FDA published an update stating that thermography was not a substitute for mammography. They stated that “thermography has not been shown to be effective as a standalone test for either breast cancer screening or diagnosis in detecting early stage breast cancer”. 

In 2019 the FDA warned that “Thermography Should Not Be Used in Place of Mammography to Detect, Diagnose, or Screen for Breast Cancer”. The CDC does not recommend thermography for breast cancer screening. 

Who uses thermography?

Thermal imaging might be valuable for the detection of other health concerns and is even being used to detect fevers in patients with symptoms of COVID-19. However no reliable medical body uses thermography for the detection of cancer. Proponents of thermal imaging for the detection and diagnosis of cancer is only recommended by alternative practitioners. 

Alternative practitioners might recommend thermography because it is non-invasive and it does not use any sort of radiation, nor is it as uncomfortable as mammograms can be. However, thermography cannot accurately detect or diagnose cancer and should not be used in place of mammography.  

Is thermography safer than mammography?

Some proponents of thermography claim that it is safer than mammography. They claim that because the breast tissue is “squashed” in order to take a mammogram, a tumour might be damaged and therefore be more likely to spread around the body. There is no evidence that tumours can be damaged in this way, or that any damage can lead to spreading of the tumour. 

Mammography has been used safely since the 1930s with the compression technique added in the 1950s. The method uses low levels of x-ray radiation to detect tumours in the breast tissue. 

There is no evidence of harm in patients with breast tumours and no evidence to support the claim that mammograms increase the risk of the cancer spreading.