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Study: Women With Dense Breast Tissue May Benefit From Regular MRIs

Breast cancer. Coloured sagittal magnetic resonance imaging (MRI) scans of a breast of a 39- year-old woman with breast cancer. The cancer (orange) has been highlighted by the injection of a gadolinium contrast medium, a contrast medium suitable for use in MRI scans. The front of the breast is at left in each scan, in these views from the side. The cancer is a ductal carcinoma, a carcinoma of the ducts that channel milk to the nipple. Ductal carcinoma is a common form of breast cancer. Breast cancer, the most common cancer in women, can be treated by surgical removal of the affected breast, often combined with radiotherapy and chemotherapy.

While there has been some controversy over when women should start getting mammograms, all experts agree that screening is an important first step in detecting breast cancers and treating them early. But for some women, that’s not enough. For the approximately 40% of women with dense breast tissue, and especially the 10% with extremely dense tissue, cancer cells are harder to detect, since the denser tissue can mask small growths. In addition, dense breast tissue itself is also a risk factor for developing cancer.

There’s been debate among experts over whether these women should have additional screening, on top of mammograms. A new study published in the New England Journal of Medicine provides the strongest data yet to support adding MRI screening to mammograms for women with extremely dense breast tissue.

Previous studies have compared rates of breast cancer in women getting mammograms alone to rates in those getting mammograms and MRI, but it hasn’t been clear that the “cancers” identified in these data sets were actually cancer. That’s because some breast cancers are what experts consider a pre-cancerous stage, known as ductal carcinoma in situ, meaning they may not grow or progress into disease.

That’s led some doctors to worry over potential over-diagnosis of breast cancer, which can lead to over-treatment of lesions that may never develop into tumors. The U.S. Preventive Services Task Force, which attempts to find answers to controversial health questions, has concluded that there is not enough evidence to advise women about the benefits or harms of adding other breast-cancer testing on top of mammograms.

In the new study, Carla van Gils, professor of clinical epidemiology of cancer at the University Medical Center Utrecht, attempted to address this concern by focusing on how many actual cancers the combination of mammogram and MRI can help to detect in women with dense breast tissue. Taking advantage of the fact that the Netherlands has a national cancer registry that includes about 99% of all diagnoses in the country, she and her team studied more than 40,000 women with extremely dense breast tissue, who were randomly assigned to screening with mammography alone or both mammography and MRI.

Each woman in the study was screened once in the two year study period (following the Netherlands’ screening guidelines that call for mammograms every other year for women over 50). Van Gils and her team analyzed how many invasive cancers were detected in between screenings, which serves as a measure for how effective the MRI was in detecting what the researchers call interval cancers—those diagnosed after a negative mammogram, and before the next mammogram was scheduled.

“If we can prevent those, we know at least we are preventing clinically relevant tumors,” says van Gils, “and not just over diagnosing.” They found that the rate of such cancers in women getting both types of imaging was 2.5 per 1,000 screenings, compared to 5 in 1,000 for women just getting mammograms.

The idea is that supplementing mammograms with MRI in the initial screening led to earlier detection of tumors that the mammograms missed which in turn contributed to lower cancer rates during a second screening, because presumably the women are seeing their doctors when suspicious growths are found and getting them treated.

The data do not confirm that combining mammograms and MRIs can lead to fewer deaths from breast cancer; that’s something van Gils will study in coming years. But documenting the reduction in cancer detected in between screenings is an important first step in showing the value of supplemental MRI for women with extremely dense breast tissue.

It also supports the reasoning behind a law passed earlier this year in the U.S. requiring that mammogram reports include an assessment of the density of women’s breast tissue, along with an explanation for why that might make mammogram results more difficult to interpret.

Van Gils notes that the results of her study aren’t robust enough yet to recommend that all women with dense breast tissue (even those with extremely dense breast tissue) should get MRIs on top of their regular mammogram screenings. For one, lowering the rates of false positives for MRIs is still a challenge; training radiologists to become more adept are reading images of dense breast tissue could help, as could applying machine learning technology to pick up subtle changes that even the best-trained human eyes cannot.

That said, if longer-term studies—enabling doctors to compare MRI readings over time to track the growth of lesions—also confirm that supplementing mammograms with MRI can lower death rates from breast cancer, it could push experts to change guidelines and give women firmer advice on how best to manage their cancer risk.

By Alice Park

November 27, 2019

Source: Study: Women With Dense Breast Tissue May Benefit From Regular MRIs | Time

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Dr. Amy Degnim, surgeon at Mayo Clinic, explains what dense breast tissue is and different types of imaging that may be recommended for breast cancer screening. To learn more about breast cancer screening, visit: https://mayocl.in/31AZAoC To request an appointment at Mayo Clinic, visit: https://mayocl.in/2QwVBoc Dense breast tissue makes breast cancer screening more difficult due to its appearance on a mammogram. Other imaging used for screening includes 3D mammogram, breast MRI, breast ultrasound and molecular breast imaging (MBI). More health and medical news on the Mayo Clinic News Network. https://newsnetwork.mayoclinic.org/

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Promising Blood Test Could Help to Predict Breast Cancer Recurrence

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Doctors have gotten much better at detecting and treating breast cancer early. Drug and chemotherapy regimens to control tumors have gotten so effective, in fact, that in some cases, surgery is no longer necessary. In up to 30% of cases of early-stage breast cancer treated before surgery, doctors can’t find evidence of cancer cells in postoperative biopsies. The problem, however, is that there is currently no reliable way to tell which cancers have been pushed into remission and which ones have not.

That’s where an easy identifier, like a blood test, could transform the way early stage breast cancer is treated. In a paper published in Science Translational Medicine, researchers led by a team at the Translational Genomics Institute (TGen), an Arizona-based nonprofit, report encouraging results on just such a liquid biopsy. Its test, called Targeted Digital Sequencing (or TARDIS), was up to 100 times more sensitive than other similar liquid-biopsy tests in picking up DNA shed by breast cancer cells into the blood.

Currently available ways of tracking breast cancer cells in the blood are most useful in people with advanced cancer. In those conditions, cancer cells litter the blood with fragments of their DNA as they circulate throughout the body to seed new tumors in other tissues like the bone, liver and brain. But in early-stage breast cancer, these cells are, by definition, scarcer.

To address the problem, the research team, which included scientists at Arizona State University, the City of Hope, Mayo Clinic, and the Cancer Research UK Cambridge Institute, developed a new way to pick up elusive cancer DNA. They genetically sequenced tumor biopsy tissue from 33 women with stage 1, 2, or 3 breast cancer, most of whom received drug or chemotherapy treatment prior to getting surgery to remove their tumors. By comparing the tumor sequence to the sequence from the patients’ normal cells, the scientists isolated potential mutations that distinguished the cancer cells and identified those that were most likely to be so-called “founder mutations”—genetic aberrations present in the original cancer cells and carried into the resulting tumor.

On average, each patient harbored about 66 such founder mutations. For each patient, the scientists combined the founder mutations to form a personalized assay, which could then be used to pick up signs of breast cancer DNA in blood samples. Combining a number of mutations together turned out to be a more sensitive way to detect tumor DNA than trying to pick up a single or a small number of mutations in an already small number of tumor DNA fragments present in the blood.

They combined this approach with a new strategy for amplifying the scarce tumor DNA found in a blood sample by preserving the size of these snippets and attaching unique molecular identifiers to them to make them more easily detectable.

At the start of the study, TARDIS was able to find tumor DNA in the blood samples of all the patients; other liquid biopsies for breast cancer currently in development have reported picking up 50% to 75% of the cancer cases.

After the pre-surgery treatment TARDIS detected circulating tumor DNA in the blood in concentrations as low as 0.003%, or 100-fold more sensitive than other tests being developed.

“This is an important advance,” says Dr. Debu Tripathy, professor and chair of the breast medical oncology department at the University of Texas MD Anderson Cancer Center, who was not involved in the study. “This test can help identify those with early stage breast cancer who may still have residual cancer in their body that may not be detectable with standard scans.”

That could help guide treatment, by, for example, determining which patients require closer monitoring for recurrent growths. Because the sequencing identifies the genetic mutations contributing to the tumor, the test could also help doctors to decide which targeted drug therapies, which are designed to address specific cancer mutations, to prescribe for their patients.

Most importantly, the test could help women whose tumors are effectively eliminated by their pre-surgery treatment to avoid an operation altogether since the blood test would reassure her and her doctor that no residual tumor DNA remained.

“If we could really know with a more accurate degree of certainty that you don’t have residual disease, it would be help in saying that you don’t need any more therapy [including surgery],” says Dorraya El-Ashry, chief scientific officer of the Breast Cancer Research Foundation. ”Conversely, if you still had residual disease, if there is information from the test that can pinpoint the next therapy, that would also be better.”

Muhammed Murtaza, co-director of the center for non-invasive diagnostics at TGen, says TARDIS needs to be tested in a larger group of breast cancer patients before it can be rolled out to doctors’ offices. His team is planning to study the test’s efficacy in about 200 breast cancer patients, in order to clarify exactly what levels of tumor DNA found in the blood are most likely to lead to recurrence. They are also exploring how modified versions of TARDIS could be applied to other cancers, like esophageal, colorectal, pancreatic and prostate.

There’s even encouraging precedent for this sort of a liquid biopsy. Doctors routinely rely on a blood test for chronic myeloid leukemia, for example, to track patients’ response to targeted drugs that treat specific mutations driving the cancer. “Applying this same technology to more common solid cancers like breast cancer is the new frontier,” says Tripathy.

By Alice Park

Source: https://time.com

 

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