Cancer places a big burden on society, with an estimated 1.7 million new cases of cancer in 2016 alone. In fact, the National Cancer Institute predicts that close to 600,000 people will die from cancer in the same year – and that’s just in the United States.
With cancer affecting various types of organs and areas in the body, fighting it may seem like an exercise in futility – but that’s often because cancers are only diagnosed during the later stages when treatment options become very limited and the fatality rate skyrockets.
The WHO emphasizes the importance of early diagnosis and screening in order to improve the survival rates of people with cancer. Especially for vulnerable members of the population who have poor access to healthcare experience delays in cancer care, diagnosis often shows cancer in its late stages — this causes an increase in avoidable deaths and disability due to cancer.
The WHO states that “early diagnosis improves cancer outcomes by providing care the earliest possible stage and is therefore an important public health strategy in all settings”.
Waves Produced By Body Tissues
When you hear the words sound waves and diagnosis, you will most likely think of ultrasound or sonography (the two are one and the same).
While sonography has long been used to diagnose a variety of conditions because it is a non-invasive technique with zero risks, there are limitations to what sound waves can produce in terms of imaging, especially if the tissue is too thick to be penetrated by said sound waves.
Enter SSI – or supersonic shear imaging. This is a newer diagnostic technique that uses shear waves or S-waves. These are different from the sound waves used in typical ultrasounds, wherein the sound waves come from the machine’s hand-held transducer – in short, the waves are completely artificial.
Shear waves, on the other hand, are waves produced by the body’s tissues. While the waves are initially induced artificially, the S-waves themselves are produced by tissue, which allows better imaging – notably in areas that are too “deep” to be seen with sonography.
These shear-waves measure the elasticity of tissue (hence the term shear-wave elastography), and this is important in detecting cancer because tumors are “stiffer” than healthy tissue.
This creates better imaging and better localization in terms of cancer diagnosis — and creates an “elastic map” of the body’s tissues. Further good news is that this procedure has a high degree of safety, because sound waves do not carry the same risk as x-rays.
Diagnoses of Cancer With S-waves
So how feasible is this? Can shear waves really be used to diagnose cases of cancer? The answer is yes. There have been quite a number of publications in the past few years that focus on shear-wave elastography in detecting cancer.
Woo, et. al. in 2017 cited shear-wave elastography (SWE) as a promising way to detect prostate cancer. Out of eight studies involved in their research, they found that SWE was able to show good diagnostic performance in diagnosis cases of prostate cancer.
On a similar note, Gomez, Gus, and Saffari found that diagnosing prostate cancer with shear was not only feasible, but it was safe as well.
The trouble with using high-intensity sound waves from typical ultrasound machines is that it can cause minute damage to tissue because artificially produced sound waves also produce heat, which can cause tissue damage or ablation.
Gomez, Gus, and Safarri found that shear waves do not cause ablation because S-waves are produced by the tissue themselves and merely “pass the wave on” to surrounding tissues to generate more waves.
Chang, et. al. in 2011 publishes a study on SWE and diagnosis of benign and malignant breast conditions, concluding that the emerging technique was able to differentiate benign from malignant breast lesions because of varying elasticity seen in the tissues — which much higher specificity compared to typically breast sonography.
Sinkus, et. al. in 2004 had very similar results with Chang, et. al. (both studies focused on the same factors — differentiating benign from malignant breast lesions). The former’s publication revealed that SWE was able to differentiate breast cancer and benign fibroadenomas of the breast.
Because of these emerging modalities in the diagnosis of various cancers, we have to place more importance on early diagnosis and screening. Shear-wave elastography shows how medically advanced society has become, with better and safer diagnostic capabilities. So don’t be scared and get screened today!
Source: Herbs-info.com / References:
National Cancer Institute. Cancer Statistics. Cancer.gov
WHO. Cancer. who.int
Bercoff, J., Tanter, M. & Fink, M. (2004). Supersonic shear imaging: a new technique for soft tissue elasticity mapping. ieeexplore.ieee.org
US Geological Survey. S wave. Earthquake.usgs.gov
Woo, S., et. al. (2017). Shear-Wave Elastography for Detection of Prostate Cancer: A Systematic Review and Diagnostic Meta-Analysis. ncbi.nlm.nih.gov
Gomez, Gus, and Saffari (2017). Use of shear waves for diagnosis and ablation monitoring of prostate cancer: a feasibility study. iopscience.iop.org
Chang, et. al. (2011). Clinical application of shear wave elastography (SWE) in the diagnosis of benign and malignant breast diseases. Link.springer.com
Sinkus, R., et. al. (2004). Viscoelastic shear properties of in vivo breast lesions measured by MR elastography. Sciencedirect.com
