Breast cancer is the most common cancer among women in Hong Kong, 1 out of 15 women suffers from this disease. Early detection allows doctors to diagnose and treat patients in the early and more treatable stages.
The U.S. Food and Drug Administration deems mammogram the best tool for breast cancer screening. A mammogram is a low-dose X-ray picture of the breast. Traditional 2D mammogram, as the name suggests, renders a 2D representation of the breast. While 2D mammogram is generally effective in detecting breast cancer, it has its limitations – small cancers masked by normal breast tissues may result in a false negative interpretation, alternatively overlapping breast tissues mimic a mass may result in a false positive interpretation. 3D mammogram, an upgrade from the traditional 2D mammogram, takes multiple images of the breast from different angles and produces a 3D image of the breast in one-millimetre slices, making it easier for radiologists to identify abnormalities, and as a result reducing the need for follow-up imaging. 3D mammogram provides a more accurate assessment of breast health while exposing women to a lower dose of radiation.
While mammography is considered the best screening tool for breast cancer available today, mammograms do not detect all breast cancers. Breast cancer screening is a collaborative effort from professionals across multiple disciplines–Doctors conduct clinical breast examination, specially trained technicians perform the mammogram procedure and radiologists interpret the diagnostic images.
To improve diagnostic accuracy, additional examinations such as ultrasound, magnetic resonance imaging and biopsy may be required. If image presents asymmetric density, breast tissues overlapping or microcalcifications, patient will be invited back to have images retaken, which is fairly common and no need to panic.
The radiation risk of mammography is extremely low. The total radiation dose for a screening mammogram is about 0.36 mSv. To put that number in perspective, it is equivalent to one-eighth of the total radiation dose a person is exposed to from his natural surroundings, or the total radiation dose a person is exposed to while
making 4 return flight journeys between Hong Kong and London. (Data source: Radiation Health Unit, Department of Health)
We use BI-RADS (Breast Imaging Reporting & Data System), a classification system developed by the American College of Radiology.
|Category||Definition||Likelihood of Cancer||Recommendations|
|0||Incomplete||N/A||Further examniation needed|
|1||Negative||Essentially 0%||Routine examination|
|2||Benign||Essentially 0%||Routine examination|
|3||Probably benign||>0%, but <2%||Early follow-up visits or biopsy|
|4a||Low suspicion||>2%, but <10%||Biopsy|
|4b||Moderate suspicion||>10% , but <50%||Biopsy|
|4c||High suspicion||>50%, but <95%||Biopsy|
|5||Highly suggestive of malignancy||>95%||Biopsy|
|6||Known biopsy - proven malignancy||100%||Surgical treatment|