Breast cancer is the most common malignant tumor afflicting the women in Taiwan. Since 2003, breast cancer tops the list of the ten major cancers. The statistics of 2015 shows that breast cancer cases increase more than 13500 annually. Though many dangerous factors might be associated with breast cancer, such as family medical history, early menophania, late menelipsis, never giving birth, giving birth after 30, using female hormone in long term, etc. However, none of the aforementioned dangerous factors are found related to more than 80% breast cancer patients, so no effective precautions could be taken so far. Women aged above 40 are still highly susceptible to breast cancer.
Is breast cancer really a fatal disease that cannot be cured ?
The result of a large-scale clinical test with approximately 500 thousand participants prove that regularly taking high-quality breast X-ray photography examination could help detect tumor two to three years earlier. At that time, the nature of tumor is only a one-centimeter and invasive cancer or preinvasive carcinoma at phase zero in comparison to the tumor of two to three centimeters in size found out by women in general breast cancer cases. Breast cancer in early stage if cured properly does not affect appearance or exercise function, and the possibility of the patients to live five years longer is higher than 90%. Therefore, WHO proposes that governments implement breast cancer examination policies step by step.
Since 2004, Bureau of Health Promotion provides the free breast cancer examination services every two years targeting the women aged between 50 and 69. By the year 2010, the age of women taking examination is adjusted to 45 and extended to 40 for those who have family medical history. However, since the examination services first provided, the rate of women taking examination is still lower than 40%, which means most women qualified to enjoy the free services did not take the examination.
Breast photography using low ration X-ray to see breast tissue is the safest and one of the most effective examination tools. However, its result is not 100% accurate. Statistics show that approximately 10% to 15% breast cancers cannot be detected, especially for the women who have high density breast issue which is the same color of bright white as tumor in the light of X-ray. If the tumor is surrounded and obscured by the dense breast issue, the performance of breast photography will be severely compromised. In this case, ultrasound scanning will be the best auxiliary examination, because the color of tumor is dark grey in the ultrasound, easily differentiated from the surrounding breast tissue. Therefore, even if the result of breast cancer examination is positive, the patients still need to be informed of the density of their breast tissue to decide whether they need auxiliary examinations such as ultrasound scanning to verify the testing result.
Can ultrasound scanning replace breast photography in breast cancer examination? The answer is no. Because the image features of breast cancer are varied, some in the form of tumor, some in the form of calcified dot which is the only characteristic of preinvasive carcinoma in the early stage. At this stage, tumor could be detected by breast photography as a bunch of small white dots in various sizes and shapes, but ultrasound scanning could reveal nothing, so it cannot be used as the first-line screening tool.
Though breast photography could detect breast cancer in early stage, its high sensitivity has disadvantages. Even if something unusual are found in the breast tissue by breast photography, most cases are not breast cancer. Generally, among 1000 women receiving breast photography examination, 80 to 100 (10%) will be notified of something unusual detected. After going through simple recheck such as ultrasound scanning or breast special diagnostic photograph, 15 of the 80 to 100 women will be found requiring tissue biopsy such as core-needle biopsy or positioning slice. Among these 15 women, two to five women will be diagnosed as breast cancer. That’s why we have to understand that due to the high sensitivity of breast photography, most cases detected turn out to be positive change such as fibrocystic change. Even so, recheck or even tissue biopsy are still necessary to confirm whether the tumor is malignant. This is the inevitable damage of breast photography examination.
The key to detect breast cancer at early stage and minimalize the damage lies in the examination quality.
It matters that hospitals use modern digital X-ray photography system, use computer-assisted diagnostic system, high resolution ultrasound scanner, observes the standard medical procedures for the positive cases, cooperates with professional medical team to complete examination procedures including professional radiologist, breast image interpreter, breast surgeon, pathologist and oncologist. As the photography technology progresses, 3D digital breast tomosynthesis passed the certification of FDA in 2011 and thereafter was put into clinical use to detect breast cancer. This advanced technology can generate 2D and 3D image at the same time compared to the general 2D digital breast photography technology, remarkably reduces the chances of tumor being hidden by dense breast tissue and increase the chances of detecting breast cancer and lower the risks of reporting false positive cases. Research results have proved that digital breast tomosynthesis can effectively improves the sensitivity and specificity of breast image interpreting. Though digital breast tomosynthesis has great potential to improve the result of breast photography examination, it is still a charged item in Taiwan. Before receiving free breast cancer examination services provided by the government, women are advised to do thorough research to thoroughly reap the benefits of breast cancer examination.