Are Ultrasounds Accurate for Diagnosing Cancer?
While ultrasounds are typically still the first step in the standard cancer diagnosis process, they are far less detailed and informative than other imaging tools. Ultrasounds use sound waves to create images of the inside of the body: a transducer (probe) transmits high-frequency sound waves into the body and captures the sound waves that bounce back to produce the image.
Generally speaking, ultrasounds are unable to provide sufficient detail about tumours in the body – especially compared to PET/CT scans. This lack of key data can lead to misdiagnosis, as well as basing treatment off of informed guesswork rather than facts.
Problems with Ultrasounds
- Ultrasounds Often Fail to Detect Cancer
Ultrasounds cannot differentiate cancerous tissue from non-cancerous tissue:
- Therefore, an ultrasound can’t tell a cancerous tumour from a benign tumour
- "Sometimes imaging tests can show something that looks like cancer, but further tests (such as a biopsy) show that it’s not cancer."
- An ultrasound cannot show whether a change is caused by cancer
- Ultrasounds are also ineffective in monitoring whether a treatment is working
- They do not clearly identify the location of all tumours in your body
- Ultrasounds Have Limited Use
Ultrasounds have limited use in some parts of the body because sound waves cannot travel through air or bone:
- Therefore, ultrasounds cannot detect tumours in the lungs or bone.
- Ultrasound images are not as detailed as images from CT scans or MRIs
- Ultrasounds Have Issues with Quality Control
The quality of ultrasound images largely depends on the skill of the professional operating the transducer (aka the wand that sends the sound waves):
- Therefore, the accuracy of your diagnosis will depend on the competency of the medical professional operating the transducer
- This is not the case for CT and MRI scans
- PET/CT scans are the most reliable, when it comes to producing images that speak entirely for themselves
- Ultrasounds Lack Sufficient Detail
An ultrasound can miss small tumours:
- "It takes millions of cells to make a tumor big enough to show up on an imaging test."
- So even if cancer cells can’t be seen on an ultrasound, your doctor might have you continue cancer treatment to make sure that they don’t miss any lingering cancer cells that may be hanging around
- This is informed guesswork, which is fine if their guess (that there are still lingering cancer cells) is correct. However, if the guess is wrong, it means that the patient is continuing chemotherapy or radiation – and causing severe harm to their body – for no reason
- Do not identify the most aggressive tumours - Therefore, doctors are unable to prioritize treatment effectively
- Ultrasounds are Problematic for Obese Patients
Because of their low-energy sound waves, ultrasounds struggle to reach through thick layers of tissue.
- Therefore, it is very difficult to get a good quality image in people who are obese
- More than one third of Americans and over 20% of Canadians are considered obese
Best Diagnostic Imaging Test for Cancer
So with all of these problems, why are ultrasounds still being used as the primary diagnostic tool for cancer? Because:
- Ultrasounds are much cheaper than other forms of imaging
- They’re fast and simple to do
- They're generally able to differentiate between solid tumours and fluid-filled cysts (though, again, they cannot tell if the tumour is cancerous)
- They don’t expose people to radiation (like CT scans do)
Ultrasounds are currently used in standard cancer treatment as the primary diagnostic tool because they’re cost effective and quick to arrange.
However, there is a much more powerful imaging tool for cancer diagnosis: the PET/CT scan, which stands for Positron Emission Tomography – Computed Tomography. A PET/CT scan can pinpoint exactly where the cancer is in your body, how aggressive it is, as well as observe the outcome of cancer treatment – making it an essential diagnostic tool in fact-based cancer treatment. Please read more about the benefits of PET/CT scans to ensure that you can make an informed decision about what diagnostic tools to use.
If you or a loved one thinks there’s a chance you might have cancer – or have received a diagnosis of cancer – please connect with us today to learn how to make the most informed decision about your cancer treatment.
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