In the last several years there have been many advances in the early detection and screening for breast cancer. JeongMi Park, MD, director of the UI Breast Imaging Center, at University of Iowa Hospitals and Clinics, talks about some of the new ways to screen and detect breast cancer at an early stage:
What is considered the most useful screening tool to detect breast cancer?
It is definitely mammogram. Mammogram is the only scientifically proven effective screening modality for breast cancer. Breast self-examination and clinical breast examination by a physician or qualified health care provider (at least once a year) are also important, but cannot replace the role of mammography because mammogram detects early stage breast cancer which is not palpable and asymptomatic.
Another piece of information is a recent large scale study including more than 40,000 patients. It shows that digital mammography can detect cancers better than conventional film-screen mammography in certain patients groups, such as women younger than 50 years old, pre- or peri-menopausal women, and those with dense breasts. The University of Iowa Breast Imaging Center is fully equipped with digital mammography units. Nationwide, approximately 40 percent of breast centers are equipped with digital mammography.
When should a woman start screening mammograms?
Starting at age 40, according to both the American Cancer Society and American College of Radiology, and once every year after that. Some patients put the date on their birthdays. However, if there are significant risk factors such as young age of diagnosis of breast cancer of the patient’s first degree relatives (mother, daughter, sister), then the starting age could be earlier than 40. (There have been long debates regarding the benefits of screening mammogram for the age group 40-49, but nowadays, it is regarded as there is enough evidence to start at the earlier age.)
What are some of the new imaging methods used to screen for breast cancer and how effective are these screening methods?
Screening ultrasound has been asked about by physicians and patients. However, ultrasound is a very operator-dependent procedure, meaning that it makes a big difference in the results according to who is doing the procedure. The American College of Radiology set very high standards for breast ultrasound performance, because otherwise it could be an almost useless or even harmful exam. Patients should ask who is doing their breast ultrasound and what are the person’s qualifications and experience.
Screening ultrasound has been tried and shows some benefits in finding small cancers not detected on mammogram, but there are also too many false positive findings—something looks suspicious on ultrasound but turns out to be a benign lesion. In other words, the patient eventually received an unnecessary biopsy; and this is with the result from the most qualified radiologists. So, screening ultrasound is not routinely recommended at this point. (The supplemental yield was 4.2 per 1000 women screened. An approximate 10 percent false positive biopsy rate—and this is even for high risk patients.)
We can do a screening MRI, too. A screening MRI is recommended for some high risk patients. The high risk factors are BRCA gene mutations, lifetime risk of breast cancer more than 20-25 percent, high dose radiation to the chest, and so on. The reported sensitivity of MRI to detect early cancer in these high risk patients is higher than mammography, with the cancer detection rate overall being approximately 10 percent.
However, screening MRI also shows a lot of false positive findings, just like screening ultrasounds, and we have to think about the cost-effectiveness, too, because it’s an expensive study. So it is not routinely recommended for non-high risk patients.
There is another method, also. Tomosynthesis is a new technology which is basically a modified digital mammographic technique. I mentioned earlier that digital mammography detects cancer better than film-screen mammography in certain patient groups. The tomosynthesis shows even higher cancer detection rates than digital mammography from a recent multi institutional study, but it is still awaiting FDA approval at this point.
How are these screening mammogram-found abnormalities handled?
Because these screening mammogram-detected cancers are so small and not palpable, with no symptom, biopsy should be done under image-guidance which is mammography-guided stereotactic core biopsy. Image-guided biopsy can be done with anything like mammography, ultrasound, or MRI.
But since these are all imaging findings with no clinical symptoms, radiologists are the primary doctors who can handle these complicated procedures appropriately. A very high level of qualification is needed to perform these procedures. And MRI-guided biopsy is not available in many institutes, but the UI Breast Imaging Center can do that. As you might already know, we are the only one in the state of Iowa designated as a Breast Imaging Center of Excellence by the American College of Radiology. This means that we are superb in our service in all ways, including technologist and radiologist training and credentialing, imaging quality assurance and quality control, diagnostic accuracy, patient follow-up, and all aspects of practice audit. We are very proud of this.
When should a woman quit screening mammograms?
Again, according to the American Cancer Society recommendation; women should continue to do yearly screening mammograms for as long as they are in good health. The incidence of breast cancer increases with age, so this recommendation makes sense.
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