Norwegian researchers reviewed large clinical trials of six common cancer screenings, including clinical laboratory tests, but some experts question the findings
Cancer screenings are a critical tool for diagnosis and treatment. But how much do they actually extend the lives of patients? According to researchers at the University of Oslo in Norway, not by much. They recently conducted a review and meta-analysis of 18 long-term clinical trials, five of the six most commonly used types of cancer screening—including two clinical laboratory tests—and found that with few exceptions, the screenings did not significantly extend lifespans.
The 18 long-term clinical trials included in the study were randomized trials that collectively included a total of 2.1 million participants. Median follow-up periods of 10 to 15 years were used to gauge estimated lifetime gain and mortality.
“The findings of this meta-analysis suggest that current evidence does not substantiate the claim that common cancer screening tests save lives by extending lifetime, except possibly for colorectal cancer screening with sigmoidoscopy,” the researchers wrote in their published paper.
The researchers noted, however, that their analysis does not suggest all screenings should be abandoned. They also acknowledged that some lives are saved by screenings.
“Without screening, these patients may have died of cancer because it would have been detected at a later, incurable stage,” the scientists wrote, MedPage Today reported. “Thus, these patients experience a gain in lifetime.”
Still, some independent experts questioned the validity of the findings.
Gastroenterologist Michael Bretthauer, MD, PhD (above), a professor at the University of Oslo in Norway led the research into cancer screenings. In their JAMA Internal Medicine paper, he and his team wrote, “The findings of this meta-analysis suggest that colorectal cancer screening with sigmoidoscopy may extend life by approximately three months; lifetime gain for other screening tests appears to be unlikely or uncertain.” How their findings might affect clinical laboratory and anatomic pathology screening for cancer remains to be seen. (Photo copyright: University of Oslo.)
As reported in these trials, “colorectal cancer screening with sigmoidoscopy prolonged lifetime by 110 days, while fecal testing and mammography screening did not prolong life,” the researchers wrote. “An extension of 37 days was noted for prostate cancer screening with prostate-specific antigen testing and 107 days with lung cancer screening using computed tomography, but estimates are uncertain.”
The American Cancer Society (ACS) recommends certain types of screening tests to detect cancers and pre-cancers before they can spread, thus improving the chances for survival.
The ACS advises screenings for breast cancer, colorectal cancer, and cervical cancer regardless of whether the individual is considered high risk. Lung cancer screenings are advised for people with a history of smoking. Men who are 45 to 50 or older should discuss the pros and cons of prostate cancer screening with their healthcare providers, the ACS states.
A CNN report about the University of Oslo study noted that the benefits and drawbacks of cancer screening have long been well known to doctors.
“Some positive screening results are false positives, which can lead to unnecessary anxiety as well as additional screening that can be expensive,” CNN reported. “Tests can also give a false negative and thus a false sense of security. Sometimes too, treatment can be unnecessary, resulting in a net harm rather than a net benefit, studies show.”
In their JAMA paper, the University of Oslo researchers wrote, “The critical question is whether the benefits for the few are sufficiently large to warrant the associated harms for many. It is entirely possible that multicancer detection blood tests do save lives and warrant the attendant costs and harms. But we will never know unless we ask,” CNN reported.
Hidden Impact on Cancer Mortality
ACS Chief Scientific Officer William Dahut, MD, told CNN that screenings may have an impact on cancer mortality in ways that might not be apparent from randomized trials. He noted that there’s been a decline in deaths from cervical cancer and prostate cancer since doctors began advising routine testing.
“Cancer screening was never really designed to increase longevity,” Dahut said. “Screenings are really designed to decrease premature deaths from cancer.” For example, “if a person’s life expectancy at birth was 80, a cancer screening may prevent their premature death at 65, but it wouldn’t necessarily mean they’d live to be 90 instead of the predicted 80,” CNN reported.
Dahut told CNN that fully assessing the impact of cancer screenings on life expectancy would require a clinical trial larger than those in the new study, and one that followed patients “for a very long time.”
“From its title, one would have expected this paper to be based on analysis of individual lifetime data. However, it is not,” he wrote in a compilation of expert commentary from the UK’s Science Media Center. “The paper’s conclusions are based on arithmetic manipulation of relative rates of all-cause mortality in some of the screening trials. It is therefore difficult to give credence to the claim that screening largely does not extend expected lifetime.”
He also questioned the inclusion of one particular trial in the University of Oslo study—the Canadian National Breast Screening Study—“as there is now public domain evidence of subversion of the randomization in this trial,” he added.
Another expert, Leigh Jackson, PhD, of the University of Exeter in the UK, described the University of Oslo study as “methodologically sound with some limitations which the authors clearly state.”
But he observed that “the focus on 2.1 million individuals is slightly misleading. The study considered many different screening tests and 2.1 million was indeed the total number of included patients, however, no calculation included that many people.”
Jackson also characterized the length of follow-up as a limitation. “This may have limited the amount of data included and also not considering longer follow-up may tend to underestimate the effects of screening,” he said.
This published study—along with the range of credible criticisms offered by other scientists—demonstrates how analysis of huge volumes of data is making it possible to tease out useful new insights. Clinical laboratory managers and pathologists can expect to see other examples of researchers assembling large quantities of data across different areas of medicine. This huge pools of data will be analyzed to determine the effectiveness of many medical procedures that have been performed for years with a belief that they are helpful.
Though still in trials, early results show tests may be more accurate than traditional clinical laboratory tests for detecting prostate cancer
Within weeks of each other, different research teams in the US and UK published findings of their respective efforts to develop a better, more accurate clinical laboratory prostate cancer test. With cancer being a leading cause of death among men—second only to heart disease according to the Centers for Disease Control and Prevention (CDC)—new diagnostics to identify prostate cancer would be a boon to precision medicine treatments for the deadly disease and could save many lives.
Thus, these are two different pathways toward the goal of achieving earlier, more accurate diagnosis of prostate cancer, the holy grail of prostate cancer diagnosis.
“There is currently no single test for prostate cancer, but PSA blood tests are among the most used, alongside physical examinations, MRI scans, and biopsies,” said Dmitry Pshezhetskiy, PhD (above), Professorial Research Fellow at University of East Anglia and one of the authors of the UEA study. “However, PSA blood tests are not routinely used to screen for prostate cancer, as results can be unreliable. Only about a quarter of people who have a prostate biopsy due to an elevated PSA level are found to have prostate cancer. There has therefore been a drive to create a new blood test with greater accuracy.” With the completion of the US and UK studies, clinical laboratories may soon have a new diagnostic test for prostate cancer. (Photo copyright: University of East Anglia.)
East Anglia’s Research into a More Accurate Blood Test
The researchers evaluated their test in a pilot study involving 147 patients. They found their testing method had a 94% accuracy rate, which is higher than that of PSA testing alone. They discovered their test significantly improved the overall detection of prostate cancer in men who are at risk for the disease.
“When tested in the context of screening a population at risk, the PSE test yields a rapid and minimally invasive prostate cancer diagnosis with impressive performance,” Dmitry Pshezhetskiy, PhD, Professorial Research Fellow at UEA and one of the authors of the study told Science Daily. “This suggests a real benefit for both diagnostic and screening purposes.”
The UK scientists hope their test can eventually be used in everyday clinical practice as there is a need for a highly accurate method for prostate cancer screening that does not subject patients to unnecessary, costly, invasive procedures.
Cedars-Sinai’s Research into Nanotechnology Cancer Testing
Researchers from Cedars-Sinai Cancer took a different approach to diagnosing prostate cancer by developing a nanotechnology-based liquid biopsy test that detects the disease even in microscopic amounts.
Their test isolates and identifies extracellular vesicles (EVs) from blood samples. EVs are microscopic non-reproducing protein and genetic material shed by all cells. Cedars-Sinai’s EV Digital Scoring Assay accurately extracts EVs from blood and analyzes them faster than similar currently available tests.
“This research will revolutionize the liquid biopsy in prostate cancer,” said oncologist Edwin Posadas, MD, Medical Director of the Urologic Oncology Program and co-director of the Experimental Therapeutics Program in Cedars-Sinai Cancer in a press release. “The test is fast, minimally invasive and cost-effective, and opens up a new suite of tools that will help us optimize treatment and quality of life for prostate cancer patients.”
The researchers tested blood samples from 40 patients with prostate cancer. They found that their EV test could distinguish between cancer localized to the prostate and cancer that has spread to other parts of the body.
Microscopic cancer deposits, called micrometastases, are not always detectable, even with advanced imaging methods. When these deposits spread outside the prostate area, focused radiation cannot prevent further progression of the disease. Thus, the ability to identify cancer by locale within the body could lead to new precision medicine treatments for the illness.
“[The EV Digital Scoring Assay] would allow many patients to avoid the potential harms of radiation that isn’t targeting their disease, and instead receive systemic therapy that could slow disease progression,” Posadas explained.
Other Clinical Laboratory Tests for Prostate Cancer Under Development
According to the American Cancer Society, the number of prostate cancer cases is increasing. One out of eight men will be diagnosed with the illness during his lifetime. Thus, developers have been working on clinical laboratory tests to accurately detect the disease and save lives for some time.
And in “UPMC Researchers Develop Artificial Intelligence Algorithm That Detects Prostate Cancer with ‘Near Perfect Accuracy’ in Effort to Improve How Pathologists Diagnose Cancer ,” we outlined how researchers at the University of Pittsburgh Medical Center (UPMC) working with Ibex Medical Analytics in Israel had developed an artificial intelligence (AI) algorithm for digital pathology that can accurately diagnose prostate cancer. In the initial study, the algorithm—dubbed the Galen Prostate AI platform—accurately detected prostate cancer with 98% sensitivity and 97% specificity.
More research and clinical trials are needed before the new US and UK prostate cancer testing methods will be ready to be used in clinical settings. But it’s clear that ongoing research may soon produce new clinical laboratory tests and diagnostics for prostate cancer that will steer treatment options and allow for better patient outcomes.
The researchers believe their test ‘could reduce the number of unnecessary prostate cancer biopsies by 32%,’ UEA reported
New diagnostic technologies may make it possible for men to provide a urine sample that can allow a clinical laboratory to not only accurately diagnose prostate cancer but also help determine whether it is an aggressive form of prostate cancer. Researchers in the United Kingdom (UK) recently described just such a test in an online, peer-reviewed journal.
Development of a non-invasive method of diagnosing prostate cancer would be significant for anatomic pathologists in the United States. In the US alone, approximately 248,000 men will be diagnosed with this type of cancer in 2021. Prostate biopsies represent a major proportion of case referrals to community pathology groups.
Moreover, were such a non-invasive test for prostate cancer also able to identify those individuals with fast-growing prostate cancers, that would help urologists make more informed treatment decisions.
A Disease Men More Commonly Die ‘With’ Rather than ‘From’
According to CDC statistics, most men over the age of 80 will have some form of slow-growing prostate cancer when they die. However, a percentage of men each year contract a rapidly growing aggressive form of the cancer, and until recently, diagnosing which cancer a patient was fighting often required multiple invasive prostate needle biopsies. But that may soon change.
Researchers at the University of East Anglia (UEA) Norwich Medical School in the United Kingdom (UK) have developed a non-invasive urine test for prostate cancer that they say also can determine the aggressiveness of the disease. Knowing this may help physicians better assess a patient’s risk prior to ordering invasive needle biopsies, a UEA article notes.
The UEA test may also allow for self-collection of the biological sample, and if it proves accurate, the test could bring additional revenue to clinical laboratories that would perform the urine testing.
“In this work we develop a test that predicts whether a patient has prostate cancer and how aggressive the disease is from a urine sample. This model combines the measurement of a protein-marker called EN2 and the levels of 10 genes measured in urine and proves that integration of information from multiple, non-invasive biomarker sources has the potential to greatly improve how patients with a clinical suspicion of prostate cancer are risk-assessed prior to an invasive biopsy,” they wrote.
“While prostate cancer is responsible for a large proportion of all male cancer deaths, it is more commonly a disease men die with rather than from,” said Daniel Brewer, PhD, one of the lead researchers on this study. “Therefore, there is a desperate need for improvements in diagnosing and predicting outcomes for prostate cancer patients to minimize over-diagnosis and overtreatment whilst appropriately treating men with aggressive disease, especially if this can be done without taking an invasive biopsy.
“Invasive biopsies come at considerable economic, psychological, and societal cost to patients and healthcare systems alike,” he added. Brewer is Senior Lecturer in Cancer Bioinformatics and a group leader within the Cancer Genetics Team at UEA’s Norwich Medical School.
Possibility of Reducing Needle Biopsies by 32%
Called “ExoGrail,” the UEA’s new test builds on their earlier development of the Prostate Urine Risk (PUR) and ExoMeth tests. The test works by integrating two biomarkers.
According to the published study, the UEA ExoGrail urine test enabled:
Results comparable to the biopsy findings.
Identification of people with prostate cancer and people without it.
Risk scoring that noted aggressive prostate cancer and need for biopsy.
Potential to reduce unnecessary biopsies by 32%.
“ExoGrail resulted in accurate predictions even when serum PSA [protein-specific antigen] levels alone proved inaccurate; patients with a raised PSA but negative biopsy result possessed ExoGrail scores significantly different from both clinically benign patients and those with low-grade Gleason 6 disease, whilst still able to discriminate between more clinically significant Gleason ≥ 7 cancers,” the researchers stated in their published study.
“The adoption of ExoGrail into current clinical pathways for reducing unnecessary biopsies was considered, showing the potential for up to 32% of patients to safely forgo an invasive biopsy without incurring excessive risk,” they noted.
Prostate Cancer Patients May Soon Have Options
While more research is needed, the new UEA Norwich Medical School ExoGrail test introduces compelling non-invasive methods for diagnosing prostate cancer. Patients with findings of aggressive cancer can proceed to biopsies, while others determined to have non-aggressive forms of prostate cancer may be able to avoid more invasive tests and the associated costs and stress.
Additionally, men may soon be able to collect their own specimens without the need to visit the primary care doctor or a patient service center.
A follow-up study underway at the University of East Anglia and the NNUH involves sending 2,000 men in the UK, Europe, and Canada home testing “prostate screening boxes” to “to collect men’s urine samples at-home,” according to a UEA new release, which noted that “the Prostate Screening Box has been developed in collaboration with REAL Digital International Limited to create a kit that fits through a standard letterbox.”
“We have developed the PUR (Prostate Urine Risk) test, which looks at gene expression in urine samples and provides vital information about whether a cancer is aggressive or ‘low risk,’” said Jeremy Clark, PhD, Senior Research Associate at UEA’s Norwich Medical School.
“The Prostate Screening Box part sounds like quite a small innovation, but it means that in future the monitoring of cancer in men could be so much less stressful for them and reduce the number of expensive trips to the hospital,” he added.
Anatomic pathologists and clinical laboratory managers will want to follow the progress of these clinical studies. A non-invasive, urine-based test for prostate cancer could be a game-changer if it can detect prostate cancer with comparable accuracy to the tissue-based diagnostics that are the current standard of care in the diagnosis of prostate cancer.
Access to vast banks of genomic data is powering a new wave of assessments and predictions that could offer a glimpse at how genetic variation might impact everything from Alzheimer’s Disease risk to IQ scores
Anatomic pathology groups and clinical laboratories have become accustomed to performing genetic tests for diagnosing specific chronic diseases in humans. Thanks to significantly lower costs over just a few years ago, whole-genome sequencing and genetic DNA testing are on the path to becoming almost commonplace in America. BRCA 1 and BRCA 2 breast cancer gene screenings are examples of specific genetic testing for specific diseases.
However, a much broader type of testing—called polygenic scoring—has been used to identify certain hereditary traits in animals and plants for years. Also known as a genetic-risk score or a genome-wide score, polygenic scoring is based on thousands of genes, rather than just one.
Now, researchers in Cambridge, Mass., are looking into whether it can be used in humans to predict a person’s predisposition to a range of chronic diseases. This is yet another example of how relatively inexpensive genetic tests are producing data that can be used to identify and predict how individuals get different diseases.
Assessing Heart Disease Risk through Genome-Wide Analysis
“Where I see this going is that, at a young age, you’ll basically get a report card,” Khera noted. “And it will say for these 10 diseases, here’s your score. You are in the 90th percentile for heart disease, 50th for breast cancer, and the lowest 10% for diabetes.”
However, as the MIT Technology Review article points out, predictive genetic testing, such as that under development by Khera and Kathiresan, can be performed at any age.
“If you line up a bunch of 18-year-olds, none of them have high cholesterol, none of them have diabetes. It’s a zero in all the columns, and you can’t stratify them by who is most at risk,” Khera noted. “But with a $100 test we can get stratification [at the age of 18] at least as good as when someone is 50, and for a lot of diseases.”
Sekar Kathiresan, MD (left), Co-Director of the Medical and Population Genetics program at Broad Institute at MIT/Harvard and Director of the Center for Genomics Medicine at Massachusetts General Hospital; and Amit Khera, MD (right), Cardiology Fellow at Mass General, are researching ways polygenic scores can be used to predict the chance a patient will be prone to develop specific chronic diseases. Anatomic pathology biomarkers and new clinical laboratory performed genetic tests will likely follow if their research is successful. (Photo copyrights: Twitter.)
Polygenic Scores Show Promise for Cancer Risk Assessment
“It was also striking how results from population-based studies were reproduced using data from electronic health records, a database not ideally designed for specific research questions and [which] is certainly not a population-based sample,” she continued.
The UCSD study highlights one of the unique benefits of polygenic scores. A person’s DNA is established in utero. However, predicting predisposition to specific chronic diseases prior to the onset of symptoms has been a major challenge to developing diagnostics and treatments. Should polygenic risk scores prove accurate, they could provide physicians with a list of their patients’ health risks well in advance, providing greater opportunity for early intervention.
An alternative to PSA-based testing, and the ability to differentiate aggressive and non-aggressive prostate cancer types, could improve outcomes and provide healthcare systems with better treatment options to reverse these trends.
While the value of polygenic scores should increase as algorithms and results are honed and verified, they also will most likely add to concerns raised about the impact genetic test results are having on patients, physicians, and genetic counselors.
And, as the genetic testing technology of personalized medicine matures, clinical laboratories will increasingly be required to protect and distribute much of the protected health information (PHI) they generate.
Nevertheless, when the data produced is analyzed and combined with other information—such as anatomic pathology testing results, personal/family health histories, and population health data—polygenic scores could isolate new biomarkers for research and offer big-picture insights into the causes of and potential treatments for a broad spectrum of chronic diseases.
Pathologists and clinical laboratory managers can expect to see new technology translated to a wide variety of diagnostic tests
Researchers claim a new diagnostic technology for detecting the HIV virus is 10 times more sensitive than traditional techniques. More remarkable is the fact that this new technology enables analyte detection at very low concentrations with the naked eye!
Pathologists and clinical laboratory managers won’t see this technology enter clinical use for some time. That is because the developers hope to deploy the accurate, fast, and very cheap HIV medical laboratory tests in Africa first. Once validated in actual clinical use, this radically innovative technology could be adapted for use in a wide variety of clinical laboratory tests.