Facts, Myths, and the Stool DNA Test

“Publicity surrounding the FDA’s approval of a stool DNA test for colorectal cancer screening made fact and fiction difficult to distinguish, according to Deborah Fisher, MD, MHS, a gastroenterologist and associate professor at Duke University in Durham, N.C. She wants to set the record straight in this guest blog.

“I am a gastroenterologist and much of my research and clinical focus is colorectal cancer screening. Some of my previous comments on the new stool DNA test, Cologuard, have already been published in the New York Times as well as on MedPage Today. However, I have recently noticed a number of misleading articles in various newspapers across the country and wanted to address these, likely common, misconceptions about the new test.

“First, I want to openly acknowledge the positives about Cologuard. The study in the New England Journal of Medicine examining its ability to find a colon or rectal cancer as a one-time test (compared to colonoscopy as the gold standard) was large, well-designed and well-executed. It showed that as a one-time test Cologuard was 92% sensitive for cancer. It also showed that the false positive rate was about 13%.

“The problem has arisen in how the study results are being spun. Here are a few emerging myths to debunk:”

Some Women Still Don’t Underststand ‘Overdiagnosis’ Risk in Breast Screening

“A third of women who are given information about the chance of ‘overdiagnosis’ through the NHS breast screening programme may not fully understand the risks involved, according to research published in the British Journal of Cancer (BJC).

“In a survey of around 2,200 women, Cancer Research UK scientists at University College London (UCL) found that 64 per cent felt they fully understood the information given about overdiagnosis – the chance that screening will pick up cancers that would never have gone on to cause any harm – by the National breast screening programme.

“But information about overdiagnosis has only been included in the NHS breast screening invitation leaflets since late 2013, meaning that overdiagnosis is likely to be a new concept for many people.

“But despite uncertainty over the information they were given, intentions to attend breast screening remained high, with only seven per cent of women saying they would be less likely to attend screening after receiving the overdiagnosis information. On the other hand, four per cent of women said they would be more likely to attend screening after receiving the information.”

Fewer Die from Colorectal Cancer

“Patients with intestinal polyps have a lower risk of dying from cancer than previously thought, according to Norwegian researchers.

“This group of patients may therefore need less frequent colonoscopic surveillance than what is common today. As a potential concequence, the researchers argue, health service resources may be diverted to other, patient groups.

“The findings were released today in The New England Journal of Medicine (NEJM).”

Talking to Men About PSA Testing

“My patient looked back at me with a blank stare. I had just finished my take on the pros and cons of having a PSA test, and he looked lost. ‘What would you do if you were me, Doc?’ he said. I had just finished explaining the decision every man faces when he turns 50: whether to be screened for prostate cancer with a prostate-specific antigen (PSA) test. The decision is still unsettled despite the results of a giant, long-term study published earlier this month in the journal The Lancet. The study did not support the use of widespread screening.

“What makes the decision so tricky? It’s partly that prostate cancer is a weird cancer. Unlike cancer of the breast or the lung or the colon, which tends to kill people within five or 10 years, prostate cancer is usually slow growing. Men tend to die with it rather than of it. In fact, many live with it for 30 years or more and never even know they have it.

“That said, 3 percent of men do die of prostate cancer. So if we had an easy, safe treatment for prostate cancer, it would make sense to screen everyone and treat all the cancers we found. But the main treatments for prostate cancer carry a high risk of causing urinary incontinence and erectile dysfunction.”

MRI Better Detects Recurrent Breast Cancer

Editor’s note: People who have been treated for breast cancer may experience a recurrence; that is, their cancer may come back. Scientists recently tested and compared different ways to detect recurrence. Out of 1,000 women, the scientists found, about 18 will have recurrent cancer that is missed by mammography and ultrasonography, but is successfully detected with MRI. The results suggest that women who have undergone breast conservation therapy might do well to be screened for recurrence using MRI.

“Single-screening breast magnetic resonance imaging (MRI) detects 18.1 additional cancers after negative findings with mammography and ultrasonography (US) per 1,000 women with a history of breast cancer, according to a study published in the August issue of Radiology.

“Hye Mi Gweon, M.D., from the Seoul National University College of Medicine in South Korea, and colleagues evaluated cancer detection rates, cancer characteristics and MRI performance characteristics in 607 consecutive women (, 48 years) with breast cancer who underwent breast conservation therapy (BCT). These women had negative mammography and US findings, and most underwent preoperative MRI examinations (91.8 percent).

“The researchers found that MRI detected 11 additional cancers (18.1 cancers per 1,000 women). The (PPV) for recall was 9.4 percent (11 of 117 examinations), PPV for biopsy was 43.5 percent (10 of 23), and the sensitivity and specificity were 91.7 percent (11 of 12) and 82.2 percent (489 of 595), respectively.”

BRCA2 Mutations Herald Poor Prognosis in Screen-Detected Prostate Cancer

Editor’s note: You may have heard about the BRCA2 mutation, which can increase a person’s risk for breast cancer. Studies have also shown that it can increase a man’s risk of prostate cancer. Studies have also shown that prostate cancer patients with BRCA2 mutations generally do not survive as long as prostate cancer patients without BRCA2 mutations. A new study explored this more in depth by looking at survival rates for BRCA2+ men who were diagnosed with prostate cancer after standard screening. These men did indeed have shorter survival times than prostate cancer patients without BRCA2 mutations. The researchers say these patients might “benefit from additional therapies, such as with cis-platinum or a PARP [poly ADP-ribose polymerase] inhibitor.”

“Among men with prostate cancer detected on screening, survival among those with a mutation in the BRCA2 gene is much poorer than in those without such a mutation, researchers report.

“The findings suggest that BRCA2 mutation carriers may warrant additional treatments to improve their prognosis, say Steven Narod (Women’s College Hospital, Toronto, Ontario) and fellow authors writing in the British Journal of Cancer.

“BRCA2 mutations are known to confer an increased risk for developing prostate cancer and also to be associated with more aggressive tumours. However, the effect of BRCA2 mutations status on mortality in the setting of screen-detected cancers is unclear.”

Screening Trial Confirms Benefit of 'Bowel Scope' Test

Editor’s note: This story is about the results of a clinical trial—a research study done with volunteer patients. The study measured the benefit of a colorectal cancer screening tool known as the Bowel Scope. The Norwegian researchers found that the number of deaths from colorectal cancer “could be reduced by as much as 27 per cent if everyone over the age of 50 had Bowel Scope testing.”

“A new trial of bowel cancer screening using flexible sigmoidoscopy – also known as Bowel Scope – has confirmed the benefits of adding the technique to existing screening programmes.

“The study, run by researchers from Norway, showed that the number of bowel cancer deaths could be reduced by as much as 27 per cent if everyone over the age of 50 had Bowel Scope testing.

“At the moment, NHS uses a screening test called the fecal occult blood test – which looks for telltale signs of bowel cancer in people’s stools.

“It is piloting the Bowel Scope test around England, with the aim of adding it to the bowel screening programme.”

Not So Simple: Why PSA Screening Needs to Change

First, a little history: the protein PSA (prostate-specific antigen) was discovered in 1970 by Richard Ablin, PhD, while searching for a way to detect prostate cancer. He determined that PSA is indeed found in most prostate cancers, but is also present in healthy prostate glands, and is therefore not useful for diagnosing the disease. However, he did find that rising levels of PSA may signal a return of cancer in patients who were treated for prostate cancer, but relapsed. Continue reading…

PCPs Commonly Fail to Offer HCC Screen to Patients with Cirrhosis

“Various primary care physicians in North Carolina who examine patients with cirrhosis do not offer a screening for hepatocellular carcinoma, according to results from a recent study.

“Researchers from the University of North Carolina, including Paul H. Hayashi, MD, MPH, used the North Carolina Medical Board database and mailed a letter and 12-item survey to 1,000 randomly assigned PCPs to address their knowledge of HCC surveillance and screening and whether they recommend it or perform it on their patients with cirrhosis. In all, 391 PCPs completed the survey and two were not included. Ninety percent of the 389 PCPs (n=345) saw patients with cirrhosis.”