Breast Cancer Screening—Early Detection is the Key to Effective Treatment
Among women, breast cancer is the most commonly diagnosed cancer and the second leading cause of cancer death. Fortunately, treatment has improved dramatically in recent years, and women today stand a better chance than ever before of beating breast cancer. To benefit from advances in science, women need to catch any cancer as early as possible —and that requires regular breast screenings with mammography. Many women avoid getting a screening because they worry about what it might entail, but Dr. Heather Greenwood, assistant professor of clinical radiology in the breast imaging section at the University of California, San Francisco, explains that there's nothing to fear in getting a breast screening—and, when early detection is the key to effective treatment, that it could save your life.
Who should get a breast cancer screening?
There are lots of different recommendations out there, but we agree with the recommendations of the American College of Radiology and the Society of Breast Imaging that every woman should get screened once a year starting at age 40.
That’s for women with average lifetime risk; women at higher risk should start screening earlier. Women with a family history of cancer—for example, women who have a first degree relative with pre-menopausal breast cancer or any male relative with breast cancer—should consider getting genetic counseling to determine their and their family’s need for genetic testing. If they test positive for a BRCA 1 or 2 gene mutation, they should start getting annual mammograms at 30 and annual breast MRI screenings at age 25. BRCA genes produce tumor suppression proteins; when these genes are mutated they cannot repair damage to DNA, and this can lead to cancer.
At the UCSF clinic, a patient can fill out her own life time risk questionnaire, which will calculate her risk of developing breast cancer based on her personal history and other risk factors. If her lifetime risk is over 20%, then we recommend an annual screening with MRI in addition to an annual mammography.
What should patients expect when they go for a breast screening?
When a patient comes to the UCSF clinic, she will first be asked to fill out a form detailing things like her family history, personal history, risk factors, or any symptoms she might have. That’s so that the interpreting radiologist has an idea of the patient’s personal risk for breast cancer. In addition, if the patient has any current worrisome symptoms, the radiologist needs to know this, as it would indicate a need for additional imaging including a diagnostic exam. (A diagnostic exam is for women who show symptoms of possible breast cancer, whereas a breast screening is the exam for asymptomatic women).
After that, she’ll change into a hospital gown, and a mammography technologist will take the patient into a room with the mammogram machine. The technician will position the patient’s breast on the machine and the breast will be gently compressed. The breast is a mobile structure so it’s necessary to compress it to hold it still to take photos. In a breast cancer screening, four routine images are obtained, two views of each breast, with the breasts in various positions. In a diagnostic examination, additional views are taken to look more closely at a specific site of concern, and a patient may also undergo a breast ultrasound.
What are some typical fears or concerns that women voice about getting a breast cancer screening?
Many women are afraid of pain when they come in for their first mammogram. They’ve heard stories that it’s necessary to compress the breast and that sounds scary. And while it’s not pleasant to have your breasts compressed, most women find that it’s tolerable and it’s not something to worry about. Even so, you should always let the technician know if you feel any pain so that they know the maximum compression you can handle. We find that once women know what to anticipate, it relieves a lot of the stress.
Many women are also afraid of what they might see. For every 1,000 women screened, 100 will be called back for additional tests. Women often think about the worst case scenario if they get called back to take additional photos, but for the vast majority, about 81 out of the 100, additional images will reveal it to be negative. Extra pictures usually clear up any questions, but occasionally there will still be abnormalities that will require further tests.
If an abnormality is detected, we’ll first take a few extra mammography pictures. If there is a mammographic abnormality such as a breast mass, often we’ll do a breast ultrasound to detect if it is solid or cystic. A cyst is a mass made of fluid; it’s a very common cause of a benign breast mass. If the ultrasound reveals a cyst, she’s done and gets to go home. But if it’s solid, most would require a small needle biopsy to see whether it’s cancerous. The majority of breast biopsies performed reveal benign, not cancerous, findings. Only a minority of women undergoing a breast biopsy are diagnosed with breast cancer.
What does a small needle biopsy entail?
In a percutaneous (through the skin) breast biopsy, we use image guidance to target breast lesions. We may use either ultrasound or mammogram pictures to help us see the breast lesion. The patient is awake and we use local numbing medicine. If we do an ultrasound, the patient lies on her back, and we use ultrasound pictures to guide us to the lesion as well as to see our needle go through the lesion. We take several samples of the breast lesion and submit the tissue to the pathologists to look at under the microscope to give a diagnosis.
What are you looking for in a breast cancer screening?
Our main goal as breast imagers is to find any cancer when it’s small and most treatable. We look for any change from previous mammograms, anything suspicious that might indicate the presence of cancer. One finding we look for is architectural distortion–if there’s something growing in the breast that might cause the breast tissue to pull abnormally; in a mammogram, it appears as a star-shape with tendrils, lots of lines radiating out from a central density or mass. We also look for breast calcifications, which could be the sign of either a benign or a malignant process. Calcifications appear as tiny bright white dots in various shapes, sizes, and distributions. Certain types and patterns of calcification may sign of early pre-invasive breast cancer, a very treatable cancer.
Other than annual screenings, when should women be alerted that they might need to get a screening? What symptoms should alert a woman to get a screening?
There’s mixed literature on the effectiveness of self-exams, but it’s good for a woman to really know her own breasts so that she can notice changes. If a patient feels a palpable lump in her breast, she should immediately schedule a consultation with her doctor to discuss getting an imaging work-up for this symptom. Anytime that a patient feels something new or different in her breast should be cause for concern; most of the time it turns out to not be cancer, but it’s a good idea to get it checked out to make sure.
If a patient has clear or bloody spontaneous discharge from her nipple, she should get it evaluated. Also if a woman has new nipple retraction, where it looks like the nipple is being pulled in, it can be concerning. Bilateral inversion is common as people age, but unilateral retraction needs to be evaluated. If it’s something that’s been that way all your life, it’s probably not something to worry about. But a new retraction could be concerning. The earlier we can detect, the better patients do, so we need women to come in as soon as they sense something new or different.
How have breast cancer screening techniques changed over the last decade?
Breast cancer imaging has improved significantly over the last decade. One big innovation is breast MRI; multiple studies have shown it to be the most sensitive imaging examination we have for the detection of breast cancer. The problem is that it also has some false positives, so it’s currently recommended only for women at high risk. Breast MRI is a 3D imaging modality that uses intravenous contrast and has no associated radiation. The patient lies in the MRI machine and we obtain different sequences both before and after intravenous injection of contrast material. Given that cancers develop vascularity, cancerous areas will “light up” on post-contrast imaging. In contrast, a mammogram is an X-ray technique, which does have a very small radiation dose.
Another big innovation has been the development of tomosynthesis. A normal mammogram produces two 2D images, but tomosynthesis is a way of seeing the breasts in 3D by acquiring multiple projections at different angles. If a woman has dense breasts, this lets us see things that would be obscured in a 2D mammogram. Tomosynthesis has increased breast cancer detection and has also decreased false positive screening mammograms. Tomosynthesis is becoming more widespread, and if a facility has it available we recommend that women ask their doctor and radiologist if it is something that would benefit them.
What else should women know about getting a breast screening?
Women feel a lot of stress from reading media articles on all the different recommendations. For a woman of average risk, starting annual breast cancer screening with mammography at age 40 is the way to save the most lives. Just know that even if you’re called back from a screening mammogram, for the vast majority of women it’s not cancer–we just need to obtain a few extra pictures to ensure everything is normal.
Whether you’re in your 20s, your 30s, or your 40s, if you feel something in your breast, get it checked. It might be nothing, but it’s better to be sure. Treatment for breast cancer has improved dramatically in the past couple decades, and in order for the benefits to matter, we need to detect the cancer early. If you have any questions, you should always ask your doctor or radiologist.