October 12, 2012
It’s that time of year again – October is breast cancer awareness month; pink everywhere – even the Giants are donning pink! But aren’t we already aware of breast cancer? We all have been directly or indirectly touched by this disease.
Maybe we are being made aware in order to remind us to get a mammogram? Early diagnosis saves lives – right?
But what if you were made AWARE that your mammogram was as accurate as a flip of a coin? That means 50 percent of cancers on your mammogram could be missed! This is the reality if you have “dense breast tissue.”
The accuracy of a mammogram is predominantly based on breast density. Mammograms are 98 percent accurate in finding tumors on fatty tissue. But 50 percent of cancers
in dense tissue are missed on mammograms because the glandular and fibrous
tissue – that’s what dense means – are white and obscure the cancers which also appear white. A mammogram on dense tissue is like a car with a blind spot – the cancer might be there, you just can’t see it.
Recent studies have shown that having dense breast tissue is in itself a risk factor for developing breast cancer – up to 4-6 times the risk when compared to women with fatty tissue. Supplemental screening is helpful in dense tissue because the images show tissue and tumors differently. Ultrasound, Magnetic Resource Imaging (MRI) and Molecular Breast Imaging (MBI) are excellent at finding cancers in dense tissue.
Mammography is still the gold standard because it has been proven time and again to save lives. Women with dense breast tissue still need mammograms because there are abnomalities that are only seen in with mammograms such as micro calcifications.
Your breast cancer awareness starts with a mammogram – but it’s just that – a start.
Here is a review of the imaging modalities I recommend – and a few that I don’t – so you know what is available, how imaging types are different from each other, and why you may or may not need to consider them. I hope this will help you navigate through all the information, sometimes confusing and conflicting, that you read:
Digital Mammography – One day we read that mammograms are great and the next day that they are useless! What’s the truth?
Mammography is excellent at finding cancers in women with fatty tissue.
Briefly, breast tissue is made of glandular, fatty and fibrous tissue.
The percentages of each vary in women mostly based on genetics. In addition as
women get older the percentage of glandular tissue may be replaced by fatty
tissue however this is not always the case and any fatty replacement may not be
At this time almost all radiology centers have replaced the older film screen mammography with digital mammography as digital provides images that can be analyzed faster and stored and shared more easily.
Ultrasound – Breast ultrasound uses sound waves that cannot be heard by humans, with no radiation, to look at the breast. A water-soluble gel is placed on the skin of the breast. A hand-held device (transducer) directs the sound waves to the breast tissue. The
transducer is moved over the skin of the breast to create a picture that can be
seen on a screen. Breast ultrasound may also be used to guide a needle during a breast biopsy. If a breast lump is found during an exam or something abnormal is seen on your
mammogram, an ultrasound can help show whether it is a solid mass or a cyst. Studies dating back to 1998 and as recent as last month have demonstrated that adding
breast ultrasound to mammography in women with dense tissue doubles the numbers
of early cancers found.
Performing hand held ultrasound requires experience and expertise of both the ultrasound technologist and radiologist scanning the Breast. In untrained hands cancers are missed (false negatives) and too many insignificant findings wind up being biopsied (false positives ). Screening ultrasounds unfortunately are not considered covered procedures by insurance and most facilities/hospitals do not offer screening breast ultrasound.
Automated Breast Ultrasound (ABUS) – This new device uses the same technology but the transducer is automated, so it is less labor intensive and less dependent on the technologist’s skill. It requires less time to perform and takes the subjectivity out of scanning. As of now it has not been proven to find more cancers than hand held breast ultrasound when hand held is performed in experienced hands.This technology will likely revolutionize the way women with dense breast tissue are screened in high volume practices that do not have the resources or the experience in performing hand held breast ultrasound.
The downside of both hand held Ultrasound and ABUS is that it finds suspicious looking but non-cancerous tissue that sometimes triggers unnecessary biopsies called false positives. A certain percentage of false positives are necessary in order to find the small
Breast Tomosynthesis – also called 3D mammography, utilizes digital mammography machines and acquires images at multiple angles. The images are then reconstructed reducing or eliminating tissue overlap in areas of concern on dense tissue.
It is a great technology for large volume practices and hospitals who perform screening mammograms that are read by the radiologist after the patient leaves the center. Tomosynthesis has been found to decrease patient call backs by 30 percent. The downside to tomosynthesis is that you are exposed to double the amount of radiation compared to a standard digital mammogram. Though it decreases patient call backs, studies have not yet demonstrated that tomosynthesis finds more cancers than mammography with the addition of ultrasound.
Molecular Breast Imaging (MBI) – With MBI, a woman is given an injection of a short-lived radioactive agent. This material accumulates in tumor cells more than it does in normal cells. Using a gamma camera, tumors show up as hot spots, or black spots, on the resulting image. This technology does not look at the anatomy of the breast as a mammogram or breast ultrasound does; it examines the ACTIVITY of the breast tissue.
This is a great technology for women with dense breast tissue, high risk patients and women with breast implants. MBI is made by several different companies. I use a system made by DIIlon Diagnostics called Breast Specific Gamma Imaging (BSGI) in my practice. In a recent Mayo Clinic study comparing MBI with mammography, MBI detected three times as many cancers in women with dense breast tissue. MBI also demonstrated fewer false positives than Breast MRI. Studies have demonstrated that MBI is more sensitive in finding invasive lobular cancers which are often hidden on mammography, Ultrasound and in physical exams. The drawback of MBI is radiation exposure, limited availability and cost.
Magnetic Resonance Imaging (MRI) –– Magnetic resonance imaging (MRI) is a noninvasive medical test that uses a powerful magnetic field, and produces detailed images of the breast tissue. It utilizes an intravenous injection of contrast. MRI does not use radiation. MRI looks at both structure and blood flow, with cancers showing increasedareas of blood flow.
MRI is very sensitive and so can reveal tumors not found on mammograms or ultrasound. The disadvantages are high false positive rate, high cost and for some women,
claustrophobia . In addition, MRI cannot be performed in women who have certain
metals such as pacemakers.