Catching Cancer Sooner: Exploring New Frontiers in Screening

The quest to find cancer early is a shared goal among patients, families, and medical professionals. Detecting cancer in its initial stages, often before symptoms even appear, dramatically increases the chances of successful treatment, improves survival rates, and can lead to less aggressive therapies, enhancing quality of life. We have powerful, evidence-based screening tools like mammograms for breast cancer, colonoscopies and stool tests for colorectal cancer, Pap and HPV tests for cervical cancer, and low-dose CT scans for individuals at high risk for lung cancer. These tests, recommended by major health organizations such as the U.S. Preventive Services Task Force (USPSTF) and the American Cancer Society (ACS), are proven lifesavers when used appropriately.   

However, a significant challenge remains: many deadly cancers currently lack effective, recommended screening tests for the average-risk population. Nearly half of all cancers diagnosed each year fall into this category, often detected only after symptoms arise, frequently at later stages when treatment is more difficult and outcomes are poorer.   

This gap has fueled innovation, leading to exciting new technologies aimed at broadening our cancer detection capabilities. Three approaches, in particular, are generating significant discussion and research:

1. Multi-Cancer Early Detection (MCED) tests: Often called "liquid biopsies," these aim to find signals of multiple cancers from a single blood draw.

2. Whole-Body Scans: Using imaging like MRI or CT to scan the entire body for suspicious growths.

3. Next-Generation Sequencing (NGS) Multi-Gene Panels: Analyzing an individual's DNA for inherited mutations that increase cancer risk.

While these technologies hold considerable promise, they are largely still evolving. They come with their own unique sets of potential benefits and significant drawbacks that require careful consideration. This article explores these novel approaches, offering a balanced look at how they work, their potential advantages, the concerns surrounding them, and where they stand in the current landscape of cancer screening.

Decoding the New Tests: How Do They Work?

Understanding the science behind these tests is the first step in evaluating their potential role.

Liquid Biopsies (MCED Tests like Galleri): The Blood Test for Many Cancers?

• The Concept: Imagine being able to screen for dozens of different cancers with a single blood test. That's the core idea behind Multi-Cancer Early Detection (MCED) tests, a specific type of "liquid biopsy".   

• The Mechanism: As tumors grow, cells within them die and break apart, releasing small fragments of their contents, including DNA, into the bloodstream. This circulating tumor DNA (ctDNA) mixes with the cell-free DNA (cfDNA) shed by normal cells.   

• The Detection: MCED tests employ sophisticated laboratory techniques, such as next-generation sequencing (NGS), combined with powerful computer algorithms (machine learning or artificial intelligence). They analyze the cfDNA in a blood sample, searching for specific "signals" or patterns characteristic of cancer cells. One key type of signal involves "methylation" patterns – chemical tags on the DNA that control gene activity (like biological light switches or unique fingerprints) which differ between normal and cancerous cells. GRAIL's Galleri test is one example that heavily relies on analyzing these methylation patterns.   

• The Multi-Cancer Aspect: The goal isn't just to find one type of cancer, but to detect signals potentially originating from many different cancer types across various organs, all from that single blood sample.   

• Predicting the Origin: Some MCED tests, including Galleri, go a step further. If a cancer signal is detected, they attempt to predict its likely source within the body, known as the Cancer Signal Origin (CSO). This prediction is crucial for guiding the necessary follow-up diagnostic tests.   

• An Important Caveat: It is critical to understand that MCED tests are screening tools, not diagnostic tests. A "Cancer Signal Detected" result indicates a possibility of cancer, but it is not a diagnosis. Confirmation always requires further medical evaluation, typically involving imaging tests (like CT or MRI scans) and potentially biopsies.   

Whole-Body Scans: A Head-to-Toe Look Inside?

• The Concept: Whole-body scanning uses medical imaging technology to create pictures of nearly the entire body, aiming to find potential tumors or other abnormalities in individuals without any symptoms.   

• The Technology: The primary technology discussed for screening purposes is Magnetic Resonance Imaging (MRI). MRI uses powerful magnets and radio waves to generate detailed images of organs and soft tissues. Crucially, MRI does not use ionizing radiation, making it generally preferred over Computed Tomography (CT) scans for screening applications. CT scans, which use X-rays, do involve radiation exposure.   

• The Goal: The objective is straightforward: to visually identify any suspicious masses, nodules, or lesions anywhere in the body that might represent an early-stage, asymptomatic cancer, allowing for earlier intervention.   

Genetic Crystal Balls (NGS Multi-Gene Panels): Reading Your Inherited Risk?

• The Concept: Unlike MCED tests looking for current cancer signals or scans looking for tumors, these genetic tests analyze an individual's own DNA, usually obtained from a blood or saliva sample. The goal is to identify specific inherited genetic changes (pathogenic variants or mutations) that are passed down through families and significantly increase a person's lifetime risk of developing certain types of cancer. It's estimated that about 5% to 10% of all cancers are linked to such inherited predispositions.   

• The Technology: Next-Generation Sequencing (NGS) technology enables laboratories to simultaneously analyze the DNA sequences of many different genes – hence the term "multi-gene panel" – much more rapidly and cost-effectively than older, single-gene testing methods.   

• The Focus: These tests assess inherited predisposition or germline risk – a potential vulnerability to developing cancer in the future – rather than detecting cancer that is already present.   

• Who Gets Tested? Genetic testing using NGS panels is typically not for the general population. It is usually considered for individuals whose personal or family medical history shows patterns suggestive of a hereditary cancer syndrome. This might include having multiple close relatives diagnosed with cancer, cancer diagnosed at an unusually young age, or specific types of cancer (like ovarian or pancreatic cancer) appearing in the family.   

  
  

The Potential Upside: What are the Hopes for These Tests?

Each of these technologies carries the hope of improving our ability to fight cancer through earlier detection or risk identification.

• MCED Tests:

  • Detecting the "Undetectable": The most significant hope is that MCED tests will allow for the earlier detection of cancers that currently lack effective screening methods, particularly aggressive cancers like pancreatic, ovarian, liver, and stomach cancer, which are often diagnosed late. Finding these cancers when they are smaller and potentially more localized could dramatically improve treatment options and survival.   

  • Broadening Early Detection's Impact: By screening for many cancers at once, MCEDs could potentially shift diagnoses towards earlier stages across a wider spectrum of malignancies, leading to better overall outcomes.   

  • Convenience: The simplicity of a blood draw might make cancer screening more accessible and acceptable to more people compared to procedures like colonoscopy or imaging tests, potentially increasing overall screening rates.   

• Whole-Body Scans:

  • Finding Hidden Tumors: The primary appeal is the potential to visually identify an asymptomatic tumor located anywhere in the body that might otherwise go undetected until a later stage.   

  • Incidental Health Discoveries: Scans may sometimes uncover unrelated, non-cancerous health issues, such as aneurysms or other conditions, that could benefit from medical attention. However, this potential benefit is often overshadowed by the high frequency of benign findings that lead to unnecessary follow-up (see Risks section). 

• NGS Multi-Gene Panels:

  • Identifying High-Risk Individuals: These tests can pinpoint individuals who have inherited a significantly increased lifetime risk for developing specific cancers due to mutations in genes like BRCA1/2, those associated with Lynch syndrome, and others.   

  • Personalized Prevention and Surveillance: Identifying high-risk individuals allows for personalized prevention strategies. This might include starting recommended screenings (like mammograms or colonoscopies) at an earlier age, undergoing screening more frequently, using additional screening modalities (like breast MRI for BRCA carriers ), taking risk-reducing medications (e.g., tamoxifen ), or considering preventative surgeries like mastectomy or removal of ovaries and fallopian tubes.   

  • Informing Family Members: A positive result in one individual provides crucial information for blood relatives, who can then consider their own testing (cascade testing) to understand their risk and take appropriate preventive measures.  

Potential Downsides and Dilemmas: What are the Concerns?

Despite the potential, these novel approaches come with significant risks, limitations, and unanswered questions that must be carefully weighed.

• MCED Tests:

  • False Positives: A major concern is the rate of false-positive results – when the test detects a cancer signal, but no cancer is actually present upon further investigation. Studies suggest this is common; one report indicated about half of positive Galleri tests did not lead to a confirmed cancer diagnosis. Such results can cause considerable anxiety, stress, and lead to a cascade of follow-up tests (imaging, invasive biopsies) that are costly, carry their own risks, and ultimately prove unnecessary. The psychological and financial burden of chasing down false alarms is a critical trade-off.   

  • False Negatives: Conversely, these tests can miss existing cancers. Test sensitivity (the ability to correctly identify people with cancer) varies depending on the cancer type and stage. Galleri's overall sensitivity was reported around 51.5% in one study, meaning it missed nearly half of the cancers present, though sensitivity increased significantly for later-stage cancers. A false-negative result can create a dangerous sense of false reassurance, potentially causing individuals to ignore symptoms or delay seeking care. A negative test does not guarantee an individual is cancer-free.   

  • Lack of Proven Mortality Benefit: This is perhaps the most critical limitation currently. Despite the intuitive appeal of earlier detection, there is no definitive evidence from large-scale, randomized clinical trials showing that using MCED tests for screening actually reduces the number of people who die from cancer. Proving a reduction in mortality is the gold standard for validating any cancer screening test.   

  • Uncertainty After Positive Result: A positive result, especially if the predicted Cancer Signal Origin (CSO) is unclear or if subsequent diagnostic tests fail to locate a tumor, leaves patients and doctors in a difficult position, unsure of the next steps and potentially facing ongoing anxiety and surveillance.   

  • Cost and Access: MCED tests like Galleri can cost several hundred dollars and are generally not covered by insurance, including Medicare, making them inaccessible for many. The costs associated with follow-up diagnostics after a positive result add to the financial burden.   

  • Regulatory Status: As of mid-2025, no MCED test has been cleared or approved by the U.S. Food and Drug Administration (FDA) specifically for cancer screening. Some are available through doctors as Laboratory Developed Tests (LDTs), which are regulated under the Clinical Laboratory Improvement Amendments (CLIA), but this pathway does not require the same level of evidence for clinical validity and utility as FDA approval. This lack of FDA approval underscores that these tests have not yet met the rigorous standards required for widespread medical use in screening.   

• Whole-Body Scans:

  • Incidental Findings ("Incidentalomas"): These scans are notorious for detecting numerous abnormalities unrelated to cancer, such as cysts or nodules in organs like the liver, thyroid, or adrenal glands. The vast majority of these "incidentalomas" are benign (harmless).   

  • Cascade of Care & Harms: The high rate of incidental findings triggers significant patient anxiety and often leads to a "cascade" of follow-up investigations. This can involve more scans, blood tests, and sometimes invasive procedures like biopsies or endoscopies to determine if the finding is cancerous. These follow-ups are costly, time-consuming, and carry their own risks, including pain, bleeding, infection, and complications from the procedures themselves, often for findings that were never a threat. The high frequency of ultimately benign incidental findings is a primary driver of harm for this screening approach.   

  • Lack of Proven Screening Benefit: There is currently no scientific evidence demonstrating that performing whole-body scans on asymptomatic individuals at average risk for cancer reduces cancer mortality or improves overall health outcomes.   

  • Cost: Whole-body scans are very expensive, potentially costing $2,000 or more, and are typically not covered by health insurance when used for general screening purposes.   

  • Radiation Exposure (CT): If CT technology is used for a whole-body scan, the individual receives a substantial dose of ionizing radiation, which carries a small but cumulative lifetime risk of potentially inducing cancer. MRI avoids this radiation risk.   

  • Potential for False Negatives/Positives: As with any imaging test, whole-body scans can potentially miss existing cancers (false negative) or identify findings that appear suspicious but are not cancer (false positive), though the issue of benign incidental findings is more prominent.   

• NGS Multi-Gene Panels:

  • Variants of Uncertain Significance (VUS): Finding a VUS is a frequent and particularly challenging outcome of multi-gene panel testing. A VUS is a change identified in a gene's DNA sequence, but current scientific knowledge is insufficient to determine whether that specific change actually increases cancer risk or is simply a harmless variation. Receiving a VUS result can cause significant anxiety and confusion for patients and their families. Critically, guidelines state that VUS results should generally not be used to make medical management decisions, such as opting for preventative surgery. The likelihood of finding a VUS increases as more genes are included in the panel. This uncertainty is a key limitation of broad panel testing.   

  • Anxiety and "Genetic Fatalism": Learning about a confirmed pathogenic variant that significantly increases lifetime cancer risk can understandably cause substantial anxiety, worry about the future, and concern for family members. Some individuals may experience "genetic fatalism," feeling that developing cancer is inevitable, which can impact psychological well-being.   

  • Insurance/Employment Concerns (GINA): While the Genetic Information Nondiscrimination Act (GINA) provides federal protection against discrimination in health insurance and employment based on genetic information, it does not cover life insurance, disability insurance, or long-term care insurance. Some individuals remain concerned about the potential for genetic information to be used negatively, despite legal protections. Understanding the scope and limitations of GINA is important.   

  • Cost: Panel testing can be expensive, and insurance coverage often depends on meeting specific medical criteria related to personal and family history.   

  • Need for Expert Genetic Counseling: Genetic testing for hereditary cancer risk is complex. Professional genetic counseling before testing (pre-test counseling) and after testing (post-test counseling) is considered essential. Counselors help individuals understand their personal risk, the appropriateness of testing, the potential results (including VUS), the implications for themselves and their families, the limitations of the test, and help them make informed decisions aligned with their values.   

  • Testing the Right Person: Genetic testing is generally most informative when it begins with a family member who has already been diagnosed with a cancer relevant to the suspected hereditary syndrome, if possible. This helps determine if a specific pathogenic variant is present in the family before testing unaffected relatives.   

To help visualize these trade-offs, the following table provides a brief comparison:

Feature	MCED Tests (e.g., Galleri)	Whole-Body Scans (MRI/CT)	NGS Multi-Gene Panels
How it Works	Analyzes blood for DNA patterns shed by cancer cells	Scans entire body with imaging (MRI/CT) to find tumors	Analyzes DNA (blood/saliva) for inherited risk mutations
Goal	Detect signals of many current cancers early	Visually detect current tumors anywhere	Identify high future cancer risk based on genetics
Potential Benefits	Detect cancers lacking screening tests Potential for improved outcomes Convenience (single blood test)	Find hidden tumors Potential incidental health findings	Identify high-risk individuals Allow personalized prevention or surveillance Inform family members
Potential Risks/Limits	High false positives (anxiety, cost, follow-up) False negatives (missed cancers) No proven mortality benefit High cost, poor insurance coverage Uncertainty after positive result Not FDA-approved for screening	High rate of benign incidental findings Anxiety, costly/risky follow-up cascade No proven screening benefit (for average risk individual) High cost, no insurance coverage Radiation (CT) Potential false negatives/positives	Variants of Uncertain Significance (VUS) Anxiety, "genetic fatalism" Insurance discrimination concerns (limited) Cost, variable insurance coverage Requires genetic counseling Not for general population screening

The Risk of Too Much Information: Understanding Overdiagnosis

One of the most complex challenges associated with highly sensitive screening tests is the phenomenon of overdiagnosis.

• What is Overdiagnosis? In simple terms, overdiagnosis occurs when a screening test detects a condition – in this case, a group of cells that meets the pathological definition of "cancer" – that, if left completely undiscovered and untreated, would never have caused any symptoms or shortened the person's life. This can happen because the detected "cancer" is extremely slow-growing, non-progressive (it stops growing or even regresses), or because the person has other health conditions and is likely to pass away from something else before the cancer ever becomes a problem. It's crucial to understand that overdiagnosis is not the same as a false-positive test (where no cancer exists) or a misdiagnosis (identifying the wrong condition). In overdiagnosis, the cells do look like cancer under a microscope.   

• How Does Screening Cause It? Cancer screening, by its nature, aims to find cancers before they cause symptoms. This process inevitably uncovers a "reservoir" of these silent, indolent, or non-lethal conditions that would otherwise have remained hidden. The more sensitive a screening test is – the better it is at finding very small or early abnormalities – the more likely it is to detect these inconsequential lesions.   

• The Link to Overtreatment: The major harm of overdiagnosis is that it almost always leads to overtreatment. Because doctors cannot reliably distinguish, at the time of diagnosis, an overdiagnosed cancer from one that will eventually become harmful or lethal, the standard approach is often to treat all detected cancers. This means individuals with overdiagnosed conditions receive treatments like surgery, radiation, or chemotherapy that they don't actually need. These treatments offer no benefit (as the condition was never going to cause harm) but expose the individual to potential side effects, complications, anxiety, and significant financial costs.   

• The Dilemma and Novel Tests: The core dilemma is the inability to know which individual diagnosis represents overdiagnosis at the time it's made. This uncertainty forces a trade-off. Highly sensitive new technologies like MCED tests and whole-body scans have the potential to detect more cancers earlier, but they also carry a significant risk of increasing the rates of overdiagnosis and subsequent overtreatment. Evaluating this balance is a critical part of ongoing research and the debate surrounding the use of these tests for screening.   

What Do the Experts Say? Current Guidelines and Recommendations

When considering any cancer screening test, it's important to know what major medical and public health organizations recommend. Guidelines from bodies like the USPSTF, ACS, NCI, and ASCO are typically based on rigorous reviews of scientific evidence.   

• The Standard for Screening Recommendations: For a screening test to be widely recommended for a specific population group, these organizations generally require strong evidence, primarily from large, well-conducted randomized controlled trials, demonstrating that the test definitively reduces the number of deaths from that cancer (a proven mortality benefit). Furthermore, the evidence must show that the potential benefits of screening outweigh the potential harms (like false positives, overdiagnosis, and complications from follow-up) for that group.   

• Established Recommendations: Based on this high standard of evidence, the USPSTF and ACS currently recommend routine screening for average-risk adults for breast cancer (mammography), cervical cancer (Pap/HPV testing), and colorectal cancer (various methods including colonoscopy and stool tests). Lung cancer screening (with low-dose CT) is recommended only for individuals at high risk due to a significant smoking history. For prostate cancer, due to uncertainties about the balance of benefits and harms, organizations like the USPSTF recommend individualized, shared decision-making between patients and providers rather than routine screening for all eligible men. Ovarian cancer screening is generally recommended against for average-risk women due to lack of benefit and potential harms. Skin cancer screening via visual exam by a clinician currently has insufficient evidence for the USPSTF to recommend for or against it in the general population.   

• Stance on Novel Tests:

  • MCED Tests: Currently, no major health organization (USPSTF, ACS, NCI, ASCO) recommends the routine use of MCED tests for cancer screening in the general population. They are widely considered investigational. The primary reasons are the lack of robust clinical trial data proving they reduce cancer mortality and significant uncertainties about their accuracy, the high potential for false positives and negatives, and the overall balance of benefits versus harms. The NCI is actively supporting research, including large-scale trials like the Vanguard study, to gather the necessary evidence.   

  • Whole-Body Scans: Leading medical bodies, including the American College of Preventive Medicine (ACPM) and the American College of Radiology (ACR), explicitly recommend against the use of whole-body scans (either MRI or CT) for cancer screening in asymptomatic individuals who are at average risk. The USPSTF does not have a specific recommendation for whole-body cancer screening, implicitly aligning with this stance. The consensus is driven by the lack of evidence for benefit in this population, the high financial cost, and the substantial potential for harm stemming from the high rate of incidental findings, patient anxiety, and the cascade of unnecessary and potentially risky follow-up procedures. While not suitable for general screening, WB-MRI may have a role in surveillance protocols for individuals with rare, specific high-risk genetic syndromes like Li-Fraumeni syndrome, but only under expert medical guidance.   

  • NGS Multi-Gene Panels: These genetic tests are not recommended for cancer risk screening in the general population. Their use is specifically targeted. Organizations like NCI, ASCO, and the National Comprehensive Cancer Network (NCCN) recommend considering these panels only for individuals who meet specific clinical criteria based on their personal and/or family history of cancer that strongly suggests an underlying hereditary cancer syndrome. Testing should always be accompanied by comprehensive pre- and post-test genetic counseling from a qualified professional to ensure informed decision-making and proper interpretation of results, including the complexities of VUS findings. The distinction here is crucial: this is targeted testing for high-risk individuals identified through clinical assessment, not broad screening of the general public.   

Putting It All Together: A Balanced View for Your Health Journey

Navigating the landscape of cancer screening can feel complex, especially with the emergence of new technologies promising earlier detection. MCED tests, whole-body scans, and NGS multi-gene panels represent exciting scientific advancements, but it's crucial to approach them with a clear understanding of their current status and limitations.

While the potential to find more cancers earlier is compelling, none of these novel approaches currently have the robust, large-scale evidence demonstrating a reduction in cancer deaths that underpins the recommendations for established screening tests like mammograms, colonoscopies, Pap/HPV tests, and targeted lung cancer screening. These established tests remain the cornerstone of effective cancer screening. The newer technologies are still largely in the research and development phase for widespread screening applications, and significant questions remain about their accuracy, the management of uncertain results, the risk of overdiagnosis, and their overall impact on health outcomes. 

Therefore, the decision to pursue any of these novel tests outside of a clinical trial setting is a highly personal and complex one. It absolutely requires a detailed conversation with a knowledgeable and trusted healthcare provider. This discussion should frankly address:   

• An individual's specific, personal risk factors for cancer (age, family history, lifestyle, etc.).

• The potential benefits the test might offer in their specific situation.

• A clear explanation of the substantial potential risks and limitations, including false positives, false negatives, incidental findings, VUS results, the potential for anxiety and costly follow-up, the possibility of overdiagnosis, and the current lack of proven mortality benefit for general screening.

• An individual's own values and tolerance for uncertainty and potential harms versus potential benefits.

Crucially, these emerging tests should not be seen as replacements for existing, guideline-recommended cancer screenings. Individuals should continue to follow the established screening schedules for breast, cervical, colorectal, and (if applicable) lung cancer as advised by their provider.   

The field of cancer detection is advancing rapidly. It's possible that, with further research and refinement, technologies like MCEDs, specialized applications of whole-body imaging, and NGS panels will find clearly defined roles in future screening paradigms. For now, however, a balanced perspective is essential. Understanding the current evidence (and lack thereof), engaging in open conversations with healthcare providers, and prioritizing proven prevention and screening strategies remain the most effective approaches for individuals taking proactive steps in their health journey.

If you'd like to discuss your personal situation and receive individualized advice, schedule an appointment with the Institute for Diabetes, Endocrinology, Adiposity, and Longevity today.

Till next time,

Dr. Koren

DISCLAIMER: The content on this webpage is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your doctor or qualified healthcare provider. Never disregard professional medical advice or delay in seeking it because of something you have read or watched on this website. The mention of any product, treatment, or organization on this website does not indicate the author's endorsement. The author disclaims any legal liability for personal injury or any other damage or loss resulting directly or indirectly from the use or misuse of this website's contents.