Breast Cancer Diagnosis
I. Executive Summary
Breast cancer is concerning a large number of female individuals worldwide. This disease comes from abnormally developed breast tissue, which usually begins in either lobules or ducts of the breast. Generally speaking, breast cancer is divided into two types—non-invasive and invasive. The core criteria to distinguish in between these two types of breast cancers is the location of cancer cells. Cancer cells remain on their initial positions for a non-invasive breast cancer, whereas they grow, or “invade”, into other areas of tissue or even organs for an invasive breast cancer. To be specific, there are four breast cancer types—DCIS (Ductal carcinoma In Situ), LCIS (Lobular carcinoma In Situ), IDC (Invasive Ductal Carcinoma), and ILC (Invasive Lobular Carcinoma). Based on the names of these four types, it is not surprising to find out that the latter two are more of concerns since they are invasive. Additionally, there are three grades of breast cancer to describe or define the state of cancer cells compared to normal tissue cells. Moreover, there are five stages (zero to four) to evaluate breast cancer and to help corresponding treatment.
Since the treatment of the breast cancer is tightly connected with the timing of detecting the cancer, it is with no doubt that earlier detection remains a priority. Therefore, certain breast imaging techniques have been developed and there have been ongoing researches on enhancing and complementing these techniques as well as developing novel imaging techniques and modalities. The three most common applied breast imaging techniques are X-ray mammography, MRI, and ultrasound. These three are the fundamental tools for breast imaging and almost every imaging modality either directly involves or references from the applications of them. However, while essential, the three techniques have their shortcomings and therefore the development of enhancement and complement is crucial.
Breast Cancer: A Lethal Disease
Breast cancer is a horrifying disease, especially for females. Breast cancer is ranked as the second leading cause of cancer death in women (FordMartin et al, 2014). In 2013, the American Cancer Society estimated that around 39,620 American women would die of breast cancer. The pathological principles underneath breast cancer are rather complex. Breast cancer derives from the developed abnormalities in breast tissue. The cancer usually starts in either lobules, which are glands that produce milk, or the ducts, which are the paths through which milk is drained from the lobules to the nipple.
In general, there are two types of breast cancer—non-invasive and invasive. Non-invasive breast cancers remain inside the milk lobules of the breast. This type of cancers does not spread into ordinary surrouding breast tissues. Non-invasive breast cancers are also termed “in situ”—which means that the cancer stays in its original place—this can be better perceived as a “pre-cancer”. After cancerous cells have already grown into surrounding normal breast tissues, the cancer becomes invasive. Sometimes the cancer spreads into other body parts, and at this point the cancer is called metastatic. Detecting breast cancer at earlier stages remains priority since non-invasive breast cancers are much easier to treat. As such, breast-imaging techniques are necessary for detecting breast tumors. Certain imaging techniques and modalities have been developed to detect breast tumor and there are ongoing researches to develop novel imaging modalities.
Breast Cancer Types
The following terminologies are to be expected in a typical breast cancer pathology report:
- DCIS (Ductal carcinoma In Situ): This is a non-invasive cancer since the cancer has not spread into normal surrounding breast tissues. Nonetheless, DCIS has a chance to develop into invasive breast cancer at later stages.
- LCIS (Lobular carcinoma In Situ): This is an unusual condition in which abnormality develops in the cells of lobules of the breast. Technically, LCIS is not a cancer, but it is a warning sign of having a high risk for the development of invasive breast cancer.
- IDC (Invasive Ductal Carcinoma): This is the most common type of breast cancer; about 80% of breast cancers are invasive ductal carcinomas. The cancer starts developing inside milk ducts and will spread into surround normal tissues of the breast.
- ILC (Invasive Lobular Carcinoma): This is the second most common type of breast cancer, ranked right after invasive ductal carcinoma; it occupies 10 % of all invasive breast cancers.
Breast Cancer Grades
Grades indicate how much cancer cells differ from normal cells. In addition to presenting what the cells look like, grade also provides an idea of how soon the cancer might grow and spread. Grade is different from stage.
- Grade 1: The cancer cells resemble normal cells, small and uniform; they are growing relatively slowly.
- Grade 2: The cancer cells are marginally larger than normal cells and have various shapes; they are growing faster than normal cells.
- Grade 3: The cancer cells look very different from normal cells; they are fast-growing.
Breast Cancer Stages
Staging is an inclusive evaluation of breast cancer based on the size of the tumor, whether the cancer is invasive or non-invasive, and whether the cancer has spread into other body places beyond the breast. The staging system is designated to organize various factors of the cancer in order to describe the breast cancer, to guide decisions on the treatment, and to predict the outcome of the cancer. In general, there are five stages:
- Stage 0: This stage indicates non-invasive breast cancers. In this stage, there is no evidence that cancers have spread into surrounding normal tissue. The most common instance of non-invasive breast cancer is DCIS.
- Stage 1: This stage indicates an early stage of invasive cancer. In this stage, cancer cells have invaded neighboring normal breast tissue but are still limited in a small area.
- Stage 2: This stage describes cancer that has grown larger but is still in a limited area of tissue. It shows the number of lymph nodes that might include cancer cells.
- Stage 3: In this stage, the size of a cancer has significantly increased compared to the size of earlier-stage caners.
- Stage 4: This stage indicates the most advanced stage of invasive breast cancer. In this stage, the cancer has spread beyond the breast to surrounding lymph nodes and to other body organs potentially including liver, lungs, and brain.
III. Major Issues and Potential Solutions
While it is a misfortune that every year a large number of people die of breast cancer, the communities of research and medical practice have reached significant achievements against this threat. It is found that, since 1989, the survival rate among breast cancer patients has increased (FordMartin et al. 2014). In general, the solutions have two major parts: diagnosis and treatment. Since the diagnosis comes first, the development of breast imaging—as an essential tool for breast cancer diagnosis—remains a high priority for greater breast cancer patients’ survival.
Summary of Essential Breast Imaging Techniques
This paper presents three essential breast imaging techniques: X-ray mammogram, ultrasound, and MRI, each of which corresponds to different cancer stages and thus serves on distinct purposes. While these three are leading the breast imaging industry, none of them is impeccable. In other words, every single essential technique has its limitations and therefore needs a supplementary support. Hence, it is also necessary to discuss complementary imaging techniques which will improve the overall outcome of imaging to help diagnose breast cancers.
X-ray mammogram plays a crucial role in breast imaging industry and it has tremendous contribution to the diagnosis of breast cancer. According to an article presented by FordMartin et al. (2014), X-ray mammogram screening provides more than 90% of detection of breast cancers. A mammogram produces a two-dimensional breast image through non-invasive X-ray. While commonly implemented in many countries, X-ray mammogram has its limitations. For instance, it is hard to get promising images on a dense breast through mammogram. Following the abnormalities detected, additional screening such as magnetic resonance imaging (MRI) and ultrasound could be done in order to help make decisions on final diagnosis.
Magnetic resonance imaging (MRI) is one of the fundamental tools for breast imaging. It can be applied for multiple purposes: in a clinical environment, it is used to define the cancer stage, to monitor adjuvant chemo-therapy, and to evaluate breast implantations. MRI is advantageous on its high sensitivity in cancer diagnosis and it also helps avoid redundant biopsies, a pain for every patient. A significant imaging modality of MRI is discussed in an article presented by Leithner, D., et al (2018): dynamic contrast-enhanced MRI (DCE-MRI), which is the basis of most MRI protocol. DCE-MRI is the most sensitive imaging modality and it assist in distinguishing lesion types—benign or malignant. It can also be applied to evaluate disease extent. Moreover, it is advantageous on assessing malignant lesions, including IDC and ILC.
Technical Issues and Solutions
Despite functioning well in detecting breast cancers, traditional X-ray mammogram has a false rate (4% – 34%) which cannot be ignored (Kosus et al, 2010). Furthermore, the sensitivity of mammogram decreases as the density of a breast increases. Patients usually have uncomfortable experience in breast being compressed. Moreover, there is a risk at which patients’ breasts get induced because of the ionizing nature of X-ray radiation. Therefore, in order to compensate for the limitations of traditional X-ray mammogram, researchers have been working to develop enhancements and complements. In the article written by Kosus et al. (2010), three techniques are proposed: digital breast mammography, breast ultrasound, and digital infrared thermal imaging.
Digital breast mammography works better than traditional X-ray mammogram on patients with dense breast; it is able to significantly improve the contrast in dense-tissue region. Furthermore, the digital nature also facilitates storing and transferring data and therefore assuring image quality. To ensure the implementation of computer-based setup, the expense of digital X-ray mammography is relatively high. As a less-pricy approach, breast ultrasound functions well on differentiating breast masses. In an ultrasound screening, patient would not be exposed to ionizing radiation, and thus the pregnant and young people could also take this screen. Usually, mammography and breast ultrasound are combined to work as an imaging modality to detect breast cancer and to help diagnosis. At last, digital infrared thermal imaging (DITI) provides additional function to the diagnosis of breast cancers. Physical information could be obtained through a DITI image, which complements for one of the things that essential imaging techniques cannot do.
One of the basic approaches, through which researchers try to get better image quality, is to increase the intensity of signals. With magnetic field increased, ultra-high-field MRI is realized (Leithner, D., et al, 2018). The advantage of this variation is that, since the intensity of signals relative to noises has been raised, images’ spatial resolution is improved. Limitations of ultra-high field MRI include rate of absorption and increasingly inhomogeneous transmit field. To summarize, MRI usually needs high cost and a prolonged screening time, and future research should be devoted to decreasing the screen time.
Brest cancer is a developed abnormality in breast tissue. While having different types and stages, invasive breast cancer is deadly—this directly corresponds to a late-stage cancer. Therefore, females are supposed to pay attention to their breast health and get regular breast scans to make sure they are healthy. This routinely check is crucial since it gives individuals a better chance to earlier discover breast cancer, if it has been developed, and therefore leaves time for patients to take corresponding treatment. On the other hand, the current mainly applied imaging techniques, including X-ray, MRI, and ultrasound, could still be improved.