BREAST CANCER
DIAGNOSIS
There are different techniques and methods that can be helpful in the diagnosis of breast cancer. While routine physical exams and for some patients, depending on age and predisposition, screening mammograms, are important to catch early signs of breast masses, a definitive diagnosis can often only be made with more invasive tools, such as a biopsy (physical removal of some tumor cells for histological analysis under the microscope) or some more advanced types of imaging (especially PET imaging, which can detect some cancers due to their increased metabolic rate). It is important for patients to know about the different types of diagnostic procedures, so they can take an active part in their diagnosis. Insisting on workup contributing to an early diagnosis of breast cancer can be life saving, because it is often crucial for treatment outcomes, remission and prognosis. Some patients, who feels a palpable mass but do not receive comprehensive diagnostic workup from their treating doctors, are encouraged to seek second opinions and further diagnostic attention from other providers, as early diagnosis and start of treatment truly do make a significant difference for treatment success.
Breast Exam
De​pending on age and predisposition (prior breast cancer or tumors, family history and genetic markers), women should get a breast exam from their treating OB/GYN every 6 months to 1 year (recommendations may vary based on individual patient history). It is also important to do regular self-checks of palpable breast masses at home, by gently massaging the breast tissue and being attentive to harder, immovable areas. Generally, masses of about 1 cm or larger can be felt on palpation, but this also depends on the location of the mass. Tumors that are in a posterior location (towards the back of the breast, close to the pectoris muscle), are sometimes not palpable at all. And conversely, when there is a palpable mass, this does not necessarily mean it is cancerous. Many palpable masses are actually benign tumors or cysts. Only a biopsy (and to some degree imaging) can give conclusive information of the identity of breast masses.
Imaging
There are different imaging techniques that can be used to identify breast masses. Basic types of imaging, which are often used initially either in a screening or diagnostic framework, are ultrasound and mammogram. An ultrasound device emits sounds waves and analyzes the frequencies and wavelengths at which sound waves are reflected by different body tissues. This provides information about the properties of the different tissues, including whether a breast mass is solid (possibly cancerous) or fluid-filled (in which case it might be a benign cyst). However, there is a risk that masses can be misclassified by ultrasound readings, for instance a breast cancer might be mistakenly identified as a benign fibroadenoma. A mammogram (can be 2D or 3D) is a particular form of X-Ray, during which the breast is compressed between two compression plates for imaging, so that the breast tissue is more completely and thoroughly visualized. X-Rays are a specific type of light wave, which allows to measure tissue density, because it is absorbed differently by tissues depending on their respective densities (denser tissues absorb, whereas less dense tissues allow the X-Rays to simply pass through). Therefore, denser tissues, such as cancerous masses, appear white (lighter) on the mammograms, whereas less dense tissues, such as muscle or fat, appear grey or black (darker). While mammograms do allow certain inferences based on the color and shape of a visualized mass, thereby making it possible to determine whether further follow-up is necessary, they are not suitable to conclusively establish whether a mass is cancerous or not. A CT (computerized tomography) is another type of X-Ray imaging that allows to visualize in 3D (though not conclusively diagnose) breast cancer. Similarly, breast masses can also be seen on MRI (magnetic resonance imaging), which uses proton alignment in a magnetic field (rather than relying primarily on radiation). Finally, PET (positron emission tomography) is a type of imaging that provides some information about the biomolecular identity of cells. In this technique, IV dye is injected prior to the imaging, which can be visualized subsequently on the PET scans. Because cancer cells (especially highly aggressive cells such as HER2-positive and Basal-type triple negative cells) have a higher metabolic rate than benign tissue cells, they will take up more of the IV dye and will therefore show up brighter on the PET images.
Biopsy
A biopsy is the best way to conclusively establish the molecular makeup of a mass and diagnose breast cancer, because a biopsy allows to remove a small tissue sample from the mass and analyze t under the microscope (histology). There are several types of biopsies.
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Fine Needle Aspiration: FNA is the least invasive type of biopsy. It is performed using a very fine needle (in fact, finer than the needles used for common blood draws), and it can be done at a regular doctor's office or medical clinic. It is usually performed without imaging guidance for breast lumps that are palpable upon exam. The fine needle allows to withdraw small portions of the cell mass for histological analysis. Although this may be sufficient to identify benign masses, such as fluid filled cysts, solid breast lumps may require a more invasive procedure for cell sample removal and analysis.
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Core Needle Biopsy: During a core needle biopsy, a slightly larger needle is inserted into the breast, usually after a small incision has been made at the side of the breast. This is the most common type of breast biopsy, and it can be performed under general or local anesthesia. It is usually done with some type of imaging guidance, most often ultrasound or fluoroscopy (X-Ray). Other imaging techniques, such MRI or mammography (stereotactic biopsy), may be used as well to visualize the progress of the needle through the breast tissue to its target (the mass). This allows for removal of tissue samples from solid masses, especially those in more posterior locations. Furthermore, tissue markers such as wires, coils or clips may be attached to the biopsied mass(es), so that they can be more easily identified upon surgical resection at a later time.
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Surgical Dissection: Though not technically a biopsy technique, patients and their doctors may sometimes opt to remove part or all of a breast lump surgically without previously obtaining a biopsy. The removed mass will then undergo histological analysis after dissection. This may be done when the mass is clearly visualized on imaging, and has well circumscribed margins (meaning, it clearly distinguishes itself from surrounding breast tissue and is not infiltrating such tissue), which is most often the case for benign masses or less aggressive Luminal A type cancer, where neoadjuvant (pre-surgical) chemotherapy is not required. In such scenarios, surgical dissection can have the advantage of reducing the number of procedures the patient has to undergo, as well as eliminating the risk of seeding (spreading) of cancer cells after biopsy.
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When imaging has shown that lymph nodes are involved, such masses can similarly be biopsied via needle biopsy (fine or core), sentinel node biopsy (removal of only the lymph node closest to the tumor) or lymph node dissection (removal of several lymph nodes, numbers can vary).
