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November 13, 2024

Living Long & Well: Full Body MRIs vs. Liquid Biopsies For Early Cancer Detection

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Living Long & Well: Full Body MRIs vs. Liquid Biopsies For Early Cancer Detection

Welcome to the fifth issue of Living Long & Well, my monthly newsletter dedicated to keeping you informed about the latest advancements in proactive health management and early cancer detection. This month, we are diving into a topic that has garnered significant interest and questions from our community: the comparison between Full Body MRIs and liquid biopsies for early cancer detection. 

Understanding Full Body MRIs and Liquid Biopsies

Full Body MRIs are imaging tests that use radio waves and strong magnets to produce detailed images of internal structures. The goal is to "see" tumors or other abnormalities in the body. Ezra's Full Body MRI scans cover up to 13 organs, providing a comprehensive overview of your health. You can read more about how MRIs work here.

Liquid biopsies, also known as circulating-tumor DNA (ctDNA) tests, detect genetic material in the bloodstream that originated from malignant tumors. These tests analyze fragments of DNA that are shed from tumors into the blood, aiming to find cancer at its earliest stages. You can read more about liquid biopsies here.

Both methods have their unique strengths and weaknesses, and understanding their differences is crucial for making informed decisions about your health.

Sensitivity and Specificity: Key Metrics

When evaluating the effectiveness of any cancer screening test, two critical metrics are used: sensitivity and specificity.

  • Sensitivity is the percentage of true positives identified by the test. For example, if 100 people with cancer are tested and 90 are correctly diagnosed, the test has a sensitivity of 90%. 
  • Specificity is the percentage of true negatives. If 100 people without cancer are tested and 90 are correctly identified as cancer-free, the test has a specificity of 90%.

Higher sensitivity means fewer false negatives (missed cancers), while higher specificity means fewer false positives (incorrect cancer diagnoses).

How Do Full Body MRIs Compare to Liquid Biopsies?

Let's break down the sensitivity and specificity of Full Body MRIs and liquid biopsies across various cancer types.

Comparison and Analysis

From the table, it is clear that Full Body MRIs generally offer higher sensitivity across various organs compared to liquid biopsies. This means that MRIs are better at detecting cancer when it is present, minimizing the chances of false negatives. On the other hand, liquid biopsies have extremely high specificity, reducing the likelihood of false positives.

Key Insights:

  • Full Body MRIs have an average sensitivity of 87% and specificity of 85%. This balance makes them highly effective for detecting a wide range of cancers early on.
  • Liquid biopsies, while having an impressive specificity of 99.5%, have an average sensitivity of 48%, indicating they are less reliable in identifying all present cancers.

Complementary Use for Optimal Screening

The different strengths of Full Body MRIs and liquid biopsies suggest that these tests should be used together for the most comprehensive screening protocol. 

  • Full Body MRIs can identify potential cancerous growths early due to their high sensitivity. This is particularly crucial as early detection significantly improves treatment outcomes.
  • Liquid biopsies can then be used to confirm the presence of cancer, leveraging their high specificity to minimize false positives and guide further diagnostic steps.

Incorporating both tests into your health regimen can provide a robust approach to early cancer detection. While the costs of these tests are not negligible (Ezra’s Full Body Flash MRI at $1,350 and GRAIL’s test at $1,000), their combined use could enhance the accuracy of screenings and ultimately lead to better health outcomes.

Conclusion

Early detection remains the cornerstone of effective cancer treatment, and utilizing a multi-modality approach significantly enhances screening accuracy. Full Body MRIs and liquid biopsies each offer unique advantages in sensitivity and specificity, respectively, making them highly complementary.

At Ezra, we are committed to advancing early cancer detection through innovative technologies and comprehensive screening protocols. Our goal is to make these life-saving tests more accessible and affordable for everyone. As always, we recommend consulting with your healthcare provider to determine the best screening strategy for your individual needs.

Stay proactive, stay informed, and take charge of your health. Until next time.