Jennifer Wholey

CHICAGO - There are few more intensely personal, and complicated, decisions than that of undergoing a mammography. In two new studies presented Tuesday at RSNA, researchers sought to quantify the impact of revised screening guidelines issued by the U.S. Preventive Services Task Force in 2009.

Researchers found that the guidelines led to a decline in screening mammograms and may lead to a significant number of missed cancers. The USPSTF recommendations moved the age of routine screening from 40 to 50, discouraged screenings after age 74 and recommended screening every two years instead of annually.

"Recommendations on screening mammography are extremely important public policy and we wanted to contribute to that dialogue," said Elizabeth Arleo, MD, assistant professor of radiology at New York Presbyterian Hospital, Weill Cornell Medical College in New York City. "We get questions all day long from patients and referring physicians on the appropriateness of screening mammography. The inconsistent information is very confusing for everyone."

Historically, the USPSTF, the American Cancer Society and the American College of Radiology have all encouraged yearly routine mammography in women 40 years of age and older. The new studies aimed to analyze the impact of the new recommendations on women ages 40 to 49 and female Medicare beneficiaries in 2010, the first full year after the new recommendations were released.

The latter study analyzed data from the Medicare Part B Physician/Supplier Procedure Summary Master Files for 2005 to 2010. Researchers calculated the annual rate of screening mammograms per 1,000 female Medicare beneficiaries. In those years, there was a 0.9 percent increase in the compound annual growth rate of mammograms, consistent with the yearly growth rate since 2001. But the change from 2009 to 2010, the year after the recommendations, was instead a 4.3 percent decrease.

It's not initially clear what caused for the abrupt drop in 2010. “It could have been that women who followed the task force recommendations over the age of 74 just stopped getting screened... Or it could also be perhaps that women extended, or decided to extend their screening interval from one to two years,” said co-author David C. Levin, MD of the department of radiology at Thomas Jefferson University Hospital in Philadelphia.

“What is clear is that the introduction of those task force recommendations in late 2009 had a chilling effect on the willingness of women to get screened. It remains to be seen whether this trend is going to continue in 2011 and beyond and whether it will affect breast cancer mortality,” he said.

To predict how the recommendations might affect women in their 40s, Arleo's retrospective study analyzed screening mammography data from 2007 to 2010.

Over the four year period, 43,351 screening mammograms were performed, of which 1,227 biopsies were recommended, which led to the detection of 205 breast cancers. 33 percent of the total mammograms were performed on women in their 40s. From these, 413 biopsies were recommended, which led to the detection of 39 breast cancers. Only 8 percent of these women had immediate relatives with premenopausal breast cancer.

"Nearly 20 percent of cancers detected with screening mammography were found among women in their 40s,” Arleo said. "It seems unacceptable to potentially miss nearly 20 percent of the breast cancers we are identifying. This, in our view, would represent a substantial degree of under-diagnosis."

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CHICAGO - USPSTF’s mammography screening guidelines to a decline in screening and may lead to a significant number of missed cancers, researchers found.

Two Studies Challenge Mammography Guideline Changes

CHICAGO - Mammograms are a fact of life for many women in America. Unfortunately, so are daytime talk shows. When one show suggested that errant radiation from mammograms may cause cancer in other parts of the body, women blanched and doctors cringed.

 presented Tuesday at RSNA 2012 found that radiation received by other organs during a mammogram is very low and does not present an increased cancer risk.

“The risk of cancer to nearby organs is indistinguishable from incidence of cancer due to other sources. The benefits of screening mammography greatly outweigh the scatter radiation to these organs,” said Alison L. Chetlen, DO, who led the study.

Chetlen and colleagues at Penn State Hershey Medical Center set out to study the radiation received by the thyroid, salivary gland, lenses of the eyes, sternum and uterus during a typical mammography and compare it to background radiation that all humans receive simply from living on Earth.

During a mammogram, some X-rays in fact do “scatter” from the beam directed at the breast, she said. While this radiation is weakened, some women became concerned that radiosensitive areas like the thyroid might absorb these extraneous rays and cause cancer later in life. They prefer to wear collars to shield them from the radiation.

As part of the study, 207 women were fitted with six tiny radiation detectors called dosimeters. Smaller than the size of the penny, these detectors measured the amount of ionizing radiation present on the skin while undergoing a two-view mammography screening. The detectors were evaluated by a health physicist and organ dose was calculated based on the skin dose and the average tissue thickness between the skin and the organ.

Researchers found that the average dose received during a screening is miniscule, less than 2 percent than the amount received annually through background radiation.

The absorbed radiation measurements were taken in milligray, mGy. The uterus, for instance, received .002 mGy of radiation during the screening. By comparison, the annual natural background dose is 3.1 millisieverts, mSv, equivalent in this study to mGy. Therefore, “screening mammography can be performed during pregnancy with no increased risk to the fetus,” Chetlen advised.

As for the thyroid, Chetlen posits that thyroid shields are unnecessary and perhaps even detrimental to the mammography process. “The thyroid gland is not radiosensitive in the age group undergoing screening mammography,” she pointed out. “We know that the thyroid collar can get in the way, so much so that if, depending on the heaviness of the patient, it can override the upper inner breast which could obscure significant findings of breast cancer. It could reduce the quality of the image, it may get in the way of the image, causing a shadow or artifact, and we'd have to retake the view.”

Chetlen noted that these are not exact measurements, but more a guideline to be considered by physicians concerning mammography radiation levels.
 

CHICAGO - Radiation received by other organs during a mammogram is very low and does not present an increased cancer risk, researchers found.

Mammography Scatter Radiation Presents No Cancer Risk

CHICAGO - Between 1980 and 2006, the per capita exposure to radiation from diagnostic imaging in America increased six-fold. And now, new research suggests that breast cancer risk estimates increase with frequent CT scans, particularly among younger patients, according to a 

“We already know there is an increased risk of cancer after an exposure to radiation that's in the same range as is delivered by imaging, particularly CT exams,” said Ginger Merry, MD, breast imaging fellow at Chicago's Prentice Women's Hospital, Northwestern Memorial Hospital and leader of the study.

Since breast tissue is known to be particularly radiosensitive, researchers aimed to examine the impact of increased imaging on radiation exposure and resulting breast cancer risk. Merry and her colleagues performed a retrospective study of about 250,000 women enrolled in a large integrated health care system between 2000 and 2010.

“We gathered data on all examinations that could deliver radiation to the breast tissue, including CT, radiography, fluoroscopy and nuclear medicine, performed by injecting a radiopharmaceutical into the blood stream. Over the 10 year period, we looked at their cumulative radiation exposure,” Merry said.

Using smaller data samples, Merry and her team were able to estimate the average radiation dose given during each examination and calculate the associated breast cancer risk. Then, they compared the imaging-risk to a baseline risk, beginning 10 years after the exposure.

"We found that the estimated breast radiation doses from CT were highly variable across patients, with the highest doses coming from multiple-phase cardiac and chest CT examinations, where successive images of the organ being studied are captured," said senior author Rebecca Smith-Bindman, MD, of the University of California, San Francisco.

More troubling, pediatric doses were more similar than expected to doses administered to adults, and when repeated CT examinations were performed at an early age, young women had an increased risk of breast cancer.

“Younger women are at the highest risk due to increased radiosensitivity of breast tissue and their longer lifespans, and therefore a longer time period in which to develop breast cancer,” Merry said.

For example, if a girl with no other familial or genetic risk factors of breast cancer were to have two chest CT scans at age 15, her risk at age 25 of developing breast cancer in the next 10 years would double. The longer the time since the exposure, the greater the risk of cancer.

To lower imaging-associated breast cancer risk, radiologists should carefully evaluate the need for imaging and monitor radiation doses given with each exam, Smith-Bindman said. Radiation exposure could also be minimized by decreasing the amount of multi-phase protocols whenever possible.

"If imaging is truly indicated, then the risk of developing cancer is small and should not dissuade women from getting the test they need," she said. "On the other hand, a lot of patients are undergoing repeat chest and cardiac CT, many of which aren't necessary. Women, and particularly young women, should understand there is a small but real potential risk of breast cancer associated with cardiac and chest CT, and the risk increases with the number of scans."

CHICAGO - Breast cancer risk estimates increase with frequent CT scans, particularly among younger patients, researchers found.

Breast Cancer Risk Increase with Repeat Imaging

CHICAGO - Radiologists can more accurately diagnose abuse of elderly patients thanks to Canadian research that points to a discernible pattern of symptoms, according to a 

Kieran J. Murphy, MD, and his colleagues at the University Health Network in Toronto conducted a meta-analysis of existing medical literature to pinpoint radiological evidence which may signal abuse.

A review of more than 1,100 cases detailing patients over the age of 60 found that certain injuries and care environments were often indicative of abuse situations. Social context in particular plays a critical role in abuse diagnosis.

“This isn't stuff that happens in a nursing home or hospital; it happens in a house and the victim is usually demented or depressed, and socially isolated except for contact with the caregiver,” said Murphy. “The signs of neglect are profound; there's often weight loss or bed sores and very poor hygiene. The caregiver is mostly a child, a daughter or a son or a grandchild, is financially or emotionally dependent upon the victim. And the caregiver may have a history of mental illness or depression.”

Radiological signs are another story entirely. Radiologic symptoms of child abuse are, sadly but fortunately, easy to recognize. The typical pattern of injuries can be simple to piece together once scrutinized by X-ray. Elder abuse, however, is much more difficult to pinpoint, with only 2 percent of cases reported, Murphy said.

“With the elderly, the challenge is that people fall,” Murphy said. The challenge is further compounded in a country like Canada, where there might be ice on the ground as many as five months of the year. The main question radiologists must ask themselves is how to identify naturally occurring injuries like slips and falls from those which were caused traumatically, he said.

Researchers found that most physical trauma as a result of abuse occurs on the head, face and neck. Dental injuries and subdural hematoma, bleeding between the outer and middle layers of the brain covering, were particularly common. Injuries to the upper torso and upper extremities were also frequently observed.

Compared to accidental injuries, abused individuals were more likely to have severe, repetitive injuries. Access to prior imaging can also be invaluable when determining abuse and because of this, radiologists can play a critical role as sentinel in identifying evidence to piece the picture together.

“A fragile elderly individual might fall over and get a subdural hemorrhages in their head, but they shouldn't get repeated hemorrhages. They shouldn't get repeated rib fractures, unless they're profoundly osteoporotic,” he said. “If you see someone with normal bone density with multiple rib fractures, you should think hey, this doesn't make sense.”

Awareness of these signs combined with the social context in which they occur should be crucial in raising suspicion, Murphy said.

CHICAGO - Radiologists can more accurately diagnose abuse of elderly patients thanks to new research that points to a discernible pattern of radiological symptoms.

Author | Jennifer Wholey

Articles

Two Studies Challenge Mammography Guideline Changes

Mammography Scatter Radiation Presents No Cancer Risk

Breast Cancer Risk Increase with Repeat Imaging

Radiologists Find Patterns Indicative of Elder Abuse