Early Ultrasound — Breast Cancer Diagnosis in Younger Women
By Kathy Hardy
Vol. 14 No. 1 P. 26
New research looks at ultrasound as a diagnostic tool for women aged 30 to 39 presenting with symptoms.
Ultrasound’s role as the second chair in an orchestra of diagnostic breast imaging tools for younger symptomatic women could change. Results from a retrospective study found that it has a higher sensitivity for cancer detection than mammography when initially evaluating for breast cancer in women younger than 40. While diagnostic criteria for women outside this demographic remain relatively standard, the analysis of women in this group continues to raise questions about the best method for accurately identifying cancers.
Currently, ACR guidelines for evaluating women aged 30 to 39 who present with focal breast concerns recommend mammography as the primary diagnostic modality, with ultrasound used in a follow-up role. In general, women considered at normal risk and younger than the age of 30 undergo breast imaging only to evaluate areas of concern, such as palpable lumps, with ultrasound as the modality of choice. With women aged 30 and older, mammography is typically the first course of action.
However, there hasn’t been a great deal of research done regarding the value of using mammography and ultrasound for symptomatic women in the 30- to 39-year-old age group, according to Constance D. Lehman, MD, PhD, lead study author. She and her fellow researchers say this study constitutes the largest analysis to date comparing ultrasound and mammography as evaluation tools for women aged 30 to 39 who present with focal breast concerns. In addition, the group says this is the only study to investigate this imaging application within the past 10 years.
“We don’t see many women under age 40,” Lehman says. “Unless they are at high risk for breast cancer, they’re not undergoing screening until age 40. Much of the data we already have is about women in their 40s. I think we’re all in agreement that women under age 40 don’t need screening. However, in the US, the age at which women are being diagnosed with breast cancer is getting younger. It’s rare, but it can occur.”
According to Lehman, a radiology professor at the University of Washington School of Medicine and the director of imaging at Seattle Cancer Care Alliance (SCCA), the use of ultrasound in women aged 30 to 39 who present with breast symptoms is common in Europe, where guidelines typically recommend ultrasound as the primary diagnostic imaging modality. With the information from this study in hand, Lehman believes there is a possibility that US guidelines could be established for women in this demographic.
“Our study is in line with the ACR’s pledge to image wisely and use radiation wisely while considering the best practices for this age group,” Lehman says.
This retrospective study included women aged 30 to 39 who had ultrasound and mammography at SCCA as a result of focal breast signs or symptoms identified between January 2002 and August 2006. Overall, researchers identified 1,208 areas of concern in 954 patients, with benign outcomes in 1,185 of those 1,208 areas of concern (98.1%) and malignant outcomes in 23 of 1,208 (1.9%). According to the study results, researchers found that breast ultrasound has 95.7% sensitivity for cancer detection at the site of focal breast concerns and 99.9% negative predictive value, contending that this demonstrates the effectiveness of ultrasound as a primary imaging modality for this patient set.
When it comes to the issue of sensitivity vs. specificity, ultrasound’s sensitivity in the patient population was 95.7%, while mammography’s sensitivity was 60.9%. However, mammography proved the leader in specificity at 94.4% compared with 89.2% for ultrasound.
“With mammography, we initially get a more comprehensive picture of both breasts, which can be very helpful in establishing a baseline reference point,” says Robin B. Shermis, MD, MPH, medical director of ProMedica Breast Care in Toledo, Ohio. “It is important to understand that, opposed to women undergoing screening, the subjects of this study were symptomatic women who presented with focal findings such as a lump or focal pain.”
Shermis notes that at ProMedica Breast Care, the staff members do not conduct screening ultrasound, only targeted ultrasound. Instead, they use MRI or molecular breast imaging for conducting screenings. “Even as early as age 30, we also will have symptomatic women undergo mammography so that we have the opportunity to find a potential abnormality elsewhere that would not be noticed by a directed ultrasound.”
He also notes that the majority of women in this study had no significant findings on a mammogram or ultrasound.
Stamatia Destounis, MD, FACR, attending radiologist at Elizabeth Wende Breast Care in Rochester, New York, sees the 30 to 39 age group as a “gray area” when it comes to protocols for breast diagnostics. This patient demographic does not undergo routine breast imaging screening; therefore, she says that if a woman presenting with a focal concern undergoes only ultrasound, there is no baseline mammogram from this period of time to compare in a follow-up exam, assuming the patient in this age group even returns for follow-up exams.
“I think there is value to this study,” Destounis says. “The results may validate and support what some radiologists are doing in their practice. But for those radiologists who perform a mammogram first in this age group with patients with a focal concern then ultrasound, they need to know that’s OK, too. I think we will need more studies, including a large prospective study that will include a wider geographic distribution area, before ACR will consider a criteria change.”
When discussing limitations of the study, there is the retrospective aspect of this analysis of patients concentrated in a single cancer center that may cause some clinicians to wonder whether the findings can be reproduced in their facilities. The study explains that SCCA is a regional tertiary care referral center serving a large, diverse geographic area with “robust adoption of an electronic medical record.” Destounis agrees that the data collection in a retrospective study such as this is important for accurate analysis and outcomes. She notes that prospective studies generally are not performed because of the expense and the long period of time that patient data needs to be collected.
“In studies like this, we’re only as good as a patient’s health history information given,” she says. “The data collected for some patients may not be accurate or complete if the patients haven’t given all the information for the electronic medical record.
“Also, they looked at the records of a specific population that presented with a focal breast concern,” she adds. “If a patient came in during that time with no focal symptom, she was excluded.”
One reason cited in the study for avoiding mammography with younger women is the desire to reduce radiation exposure in this age group. Although the risk of cancer attributed to radiation from mammography is still up for debate, the radiology community continues to try to image wisely and limit radiation. With that, the study states that using ultrasound with symptomatic women under the age of 40 would enable radiologists to be more selective with mammography in this demographic, possibly reserving mammography for younger women at high risk. In the end, patients should be exposed to radiation only if the benefits of the imaging test outweigh the potential and real risks, the study says.
“We don’t want to discourage women from having screening mammograms,” Lehman says. “But women under age 40 with a lump or mass can undergo ultrasounds with no compressions or radiation. Also, women undergoing ultrasound can benefit from interaction with the technologist or radiologist performing the exam, telling them where the lump is located.”
Along with radiation reduction, the study addresses a potential reduction in patient anxiety by providing the specificity of ultrasound images for their diagnosis. However, Shermis points to what could be missed without a mammogram. “I think there’s more anxiety about not knowing what you have than about undergoing more than one exam,” he says. “I would rather use two modalities to attack a problem.”
Whether it’s one imaging modality or several, Mary Hayes, MD, medical director of women’s imaging for Memorial Healthcare System Hospitals in Pembroke Pines, Florida, says she likes the latitude that comes with studies such as this one, particularly when dealing with women in the demographic examined here. Setting a “hard-and-fast rule” with specific appropriateness criteria may not be easy to apply to these women. “This is not a black and white issue,” she says. “I think a balance of modalities could help when imaging this group of patients.”
Hayes cites the number of clinical variables when it comes to determining best imaging practices for women aged 30 to 39. For example, women with an average to low breast cancer risk who present with a palpable lump but are pregnant would undergo ultrasound first. Mammography would be used only with the discovery of something suspicious. A high-risk patient in that demographic with a family history of breast cancer discovered at the age of 40 would have both mammography and ultrasound “in any order,” she says.
“This is not a one-size-fits-all group,” Hayes says. “With that, this is just one study. It’s a good study, but it needs to be validated. The work was done in an environment where this was a concentrated subspecialty of breast imaging. It would be good to set criteria for a larger nationwide study group.”
ACR guidelines aside, Lehman notes that individual practices can choose, and in many cases have chosen, to adopt protocols that mirror the findings of this study. “I’m pleased with how nimble organizations have been with incorporating ultrasound first into their protocols for women in this age range who present with a palpable lump,” she says. “But, there are still guidelines for women aged 30 to 39 that differ from that.”
Destounis agrees that this study is a good example of how practices can set their own protocols for breast diagnostic imaging supported partly by these findings as long as they follow the same protocols for each patient who presents with symptoms that warrant ultrasound imaging. “These types of studies give practices and radiologists something to discuss and consider incorporating into their protocols,” she says.
However, the study’s protocol may not be manageable for some practices, particularly those located in small communities with limited resources. It needs to be established that the study findings where the ultrasound exam is performed by the radiologist will correlate similarly with the differing protocols across the country, Destounis says. “In most community settings, the radiologist is not performing the ultrasound,” she says. “A technologist is doing the exam. In our practice, the radiologist performs the ultrasound. That means I can do a clinical exam at the same time and communicate with the patient, so it’s actually a multifaceted exam. Not all practices have the resources to do that.”
However, Hayes notes that radiologists can establish “preferential lists” for their technologists to follow, outlining which studies to perform based on certain algorithms based on patient age, family history, and other factors.
As practices, and even the ACR, consider this latest breast imaging development for women aged 30 to 39, Lehman says she could see a more broad application of ultrasound as the initial tool of choice for diagnostic breast imaging. Patients aged 40 and older, where the incidence of breast cancer increases, also could benefit from a sensitive first approach to diagnosing disease, she says.
“Why should the course of action for a woman in her 40s who has a lump in her breast be different than it is for younger women?” she asks. “I’m not sure that more mammograms make more sense.”
— Kathy Hardy is a freelance writer based in Phoenixville, Pennsylvania. She primarily covers women’s imaging for Radiology Today.