Breast Cancer

1. Mammography

This is an X-ray imaging test performed by compressing the breast tissue. It is essential for the early detection of breast cancer, allowing for relatively accurate identification of not only masses but also microcalcifications. In particular, irregular margins of breast tissue on imaging may raise suspicion of malignancy.

2. Breast Ultrasonography

This test is useful for detecting the presence of a breast mass and distinguishing between cystic (fluid-filled) and solid tumors. It is especially helpful in individuals with dense breast tissue, where abnormalities may not be easily visible on mammography alone. When combined with ultrasound, diagnostic accuracy can be significantly improved.

3. Breast MRI

MRI enables highly detailed assessment of the size, location, and potential lymph node involvement of the tumor. It is valuable not only for diagnosis and staging, but also for evaluating the tumor’s response before and after treatment.

4. Biopsy

A definitive diagnosis of breast cancer is made through a biopsy. If a suspicious mass is identified, imaging studies such as mammography and breast ultrasonography guide the collection of tissue using a needle or surgical excision of the lesion. The appropriate biopsy method is selected based on the tumor’s size, location, shape, and number.

• 4-1) Pathology

Pathology is a field of the medical examaination that focuses on evaluating the morphological features and discovering the abnormal findings of human tissues from biopsy using a microscope or digital pathology system to diagnose diseases. The final diagnosis of patients should be confirmed under histopathologic examination of human tissues from surgery.

• 4-2) Immunohistochemistry 

Immunohistochemistry is a method of pathologic examination that visualizes characteristics of a tumor using antigen-antibody reactions. It is essential for diagnosing breast cancer and determining treatment strategies. Immunohistochemistry provides the characteristics of breast cancer, such as estrogen receptor (ER), progesterone receptor (PR) and human epidermal growth factor receptor-2 (HER2), which are crucial information to clinicians in choosing appropriate treatment.

After a diagnosis of breast cancer, additional tests are required to determine the stage of the disease. Common staging evaluations include chest CT, abdominal CT, and bone scan. If necessary, PET-CT or other advanced imaging studies may also be performed to assess potential metastasis and guide treatment planning.

1. Computed tomography (CT) 

CT scans of the chest and abdomen are performed to evaluate whether the cancer has spread to nearby organs such as the lungs, liver, or regional lymph nodes (including axillary, supraclavicular, or internal mammary nodes).

Contrast-enhanced CT helps provide detailed cross-sectional images, enabling physicians to detect small metastases that may not be visible on basic imaging. This test is typically used for patients with invasive cancer, especially if lymph node involvement or symptoms suggesting distant spread are present.

2. Bone scan 

A bone scan is a type of nuclear medicine imaging that uses a radiotracer to evaluate osteoblastic (bone-forming) activity throughout the body. It is especially useful for detecting bone metastases, as most metastatic lesions in the bone show increased osteoblastic activity, leading to greater uptake of the radiotracer in those areas. Because breast cancer commonly spreads to the bones, a bone scan is often included as part of the initial staging process after diagnosis. It is also used during follow-up to monitor for possible bone metastases or when other imaging studies raise concerns about bone metastasis. This test helps guide further treatment decisions and disease management.

3. PET-CT 

PET-CT combines functional imaging (PET) with anatomical imaging (CT), providing comprehensive information about disease status of cancer. FDG PET-CT uses a radioactive form of glucose (FDG) to detect cancer, since tumor cells tend to absorb more glucose than normal cells. In breast cancer, FDG PET-CT is particularly helpful when there is suspicion of widespread lymph node involvement or distant metastasis, as it can visualize disease throughout the body in a single scan. It is also useful during follow-up to detect cancer recurrence or to evaluate suspicious findings from other imaging tests.

In estrogen receptor (ER)-positive tumors, a specialized scan called FES PET-CT may be performed. This test uses a tracer that targets estrogen receptors, allowing for more specific detection of metastatic lesions based on hormone receptor status.

A. Surgical Treatment

Surgical treatment of breast cancer is broadly divided into breast surgery and axillary  lymph node surgery.

1. Breast Surgery

Breast surgery includes two main types: breast-conserving surgery (BCS) and mastectomy.

• Breast-conserving surgery involves removing the tumor along with a margin of surrounding tissue, preserving most of the breast. This approach is appropriate when the tumor is relatively small or has been reduced in size through neoadjuvant chemotherapy.
• Mastectomy involves the complete removal of breast tissue and is typically performed in cases of advanced, large, or multifocal tumors. For patients undergoing mastectomy, immediate or delayed breast reconstruction may be offered to enhance cosmetic outcomes and improve quality of life.

2. Axillary Lymph Node Surgery

Surgery involving the axillary lymph nodes includes sentinel lymph node biopsy (SLNB) and axillary lymph node dissection (ALND).

• The sentinel lymph node is the first lymph node to which cancer cells are likely to spread. SLNB is a procedure to determine whether cancer has metastasized to the lymph nodes.
• If cancer is detected in the sentinel node, further surgery such as ALND may be necessary to remove additional lymph nodes.

Based on updated medical guidelines, doctors may decide not to perform sentinel lymph node biopsy in some early-stage breast cancer patients, if no signs of lymph node involvement are found on imaging tests. This helps reduce the need for unnecessary surgery while still following safe and effective treatment practices.

3. Breast reconstruction

Breast reconstruction surgery after mastectomy is a procedure that restores the breast removed due to breast cancer to a shape similar to its original form. It is an extension of breast cancer treatment, aimed at helping patients regain their confidence as women and restore physical balance, ultimately supporting a healthy and fulfilling life after cancer therapy.

Breast reconstruction can be categorized by its timing:

• Immediate Reconstruction is performed at the same time as the mastectomy,
• Delayed Reconstruction is done after all additional treatments—such as chemotherapy or radiation—are completed and a sufficient observation period confirms there is no recurrence.

Immediate reconstruction is generally suitable for patients with early-stage breast cancer (stages I–II) who are less likely to require postoperative radiation. Both implant-based and autologous (using the patient's own tissue) reconstruction methods can be used in these cases. For patients who are expected to undergo radiation therapy after mastectomy, delayed reconstruction is usually more appropriate. In such cases, reconstruction using autologous tissue is often preferred over implants, as it better tolerates radiation and is associated with fewer complications.

Reconstruction methods are broadly divided into two types:

• Implant-Based Reconstruction: This involves tissue expanders and implants. Its advantages include shorter surgery time, quicker recovery, and the absence of donor site scars since no tissue is taken from other parts of the body. However, it is more vulnerable to complications after radiation therapy and may result in issues such as capsular contracture or implant exposure. Additionally, achieving a naturally drooping breast shape is more difficult with implants.
• Autologous tissue-Based Reconstruction: This method uses the patient’s own tissue, such as abdominal or back tissue. While it requires a longer surgery and recovery period and leaves additional scars at the donor site, it offers a more natural breast shape and texture. It also has a lower complication rate and better outcomes, especially in patients undergoing radiation therapy.

B. Adjuvant treatment 

1. Radiotherapy

Radiotherapy is an essential component of breast cancer treatment. It uses high-energy radiation to destroy residual cancer cells after surgery, reducing the risk of recurrence and improving long-term outcomes.

1-1). When is Radiotherapy Used?

Radiotherapy may be recommended in the following situations:

• After breast-conserving surgery (lumpectomy) to treat remaining breast tissue
• After mastectomy in patients with large tumors or lymph node involvement
• For regional lymph node irradiation (axillary, supraclavicular, internal mammary nodes) when there is lymphatic spread

2-1). Types of Radiotherapy

• Whole Breast Irradiation (WBI)
• Partial Breast Irradiation (PBI) – for selected patients with low-risk early breast cancer
• Chest Wall and Regional Nodal Irradiation – for advanced or node-positive cases

3-1). Radiotherapy Fractionation

"Fractionation" refers to how the total dose of radiation is divided into individual sessions. Modern radiotherapy offers several options:

Conventional Fractionation:

• Daily doses of 1.8–2.0 Gy over 5 to 7 weeks.

Moderate Hypofractionation:

• Slightly larger daily doses (e.g., 2.66 Gy), typically over 3 to 4 weeks.
• Proven to be equally effective and is now a widely accepted standard for early-stage breast cancer.

Ultrahypofractionation:

• Higher doses per session, completed in 5 treatments over 1 week.
• Supported by recent clinical trials and increasingly adopted for suitable low-risk patients.

4-1). Advanced Radiotherapy Modalities

While X-ray (photon) radiotherapy is the standard, newer radiation techniques offer additional options, particularly for selected cases:

• X-ray (Photon) Radiotherapy:
  X-rays, or photons, are the most commonly used form of radiation for breast cancer treatment. These high-energy beams pass through the body and deposit radiation along their path, including both the tumor and nearby normal tissues.
  
  Modern delivery techniques such as 3D conformal radiotherapy (3D-CRT), intensity-modulated radiotherapy (IMRT), and image-guided radiotherapy (IGRT) help target the tumor more precisely while minimizing exposure to healthy organs.
  
  Photon radiotherapy is widely accessible, clinically proven, and remains the standard of care for most breast cancer patients.

• Proton Therapy:
  
  Proton beams deliver radiation with a unique physical property called the Bragg peak, which allows the radiation dose to stop precisely at the tumor site, reducing unnecessary exposure to surrounding healthy tissues such as the heart and lungs.
  
  This is particularly beneficial in left-sided breast cancers, younger patients, or those at high risk of cardiac toxicity.

• Carbon-Ion Therapy:
  
  Carbon ions are heavier particles that also exhibit the Bragg peak, but they release more concentrated energy and have a higher biological effectiveness compared to photons or protons.
  
  Although still under limited clinical use and ongoing research for breast cancer, carbon-ion therapy may be considered for radioresistant tumors or re-irradiation in specialized centers or clinical trials.

5-1). Treatment Process

Radiation is typically administered once a day, five days a week, using techniques such as:

• 3D Conformal Radiotherapy (3D-CRT)
• Intensity-Modulated Radiotherapy (IMRT)
• Image-Guided Radiotherapy (IGRT)

These technologies help deliver precise doses to the target while minimizing radiation to surrounding organs.

6) Side Effects

Most patients tolerate breast radiotherapy well. Common side effects include:

• Skin changes (redness, dryness, irritation)
• Breast swelling or firmness
• Fatigue

Serious complications are rare, especially with modern techniques, but may include lung fibrosis or cardiac effects, particularly in left-sided breast cancers—hence the potential value of proton therapy in selected cases.

2. Systemic Treatment 

2-1) Hormone (endocrine) therapy 

Adjuvant hormone therapy is an additional treatment some patients receive after breast cancer surgery. Its main purpose is to lower the risk of the cancer coming back by targeting any cancer cells that might remain in the body. This therapy is specifically for individuals whose breast cancer is "hormone receptor-positive" (often called ER-positive or PR-positive), meaning the cancer cells use natural hormones like estrogen to grow. Since a large majority of breast cancers, about 70–80%, are hormone receptor-positive, this type of therapy is a very common and important part of treatment for many patients.

Hormone therapy works in a couple of ways: either by using medicines to block these hormones from reaching the cancer cells, or by reducing the amount of these hormones your body makes. The most common forms are daily pills, such as tamoxifen or a group of drugs called aromatase inhibitors (AIs), and treatment typically lasts for five to ten years. The significant benefits include reducing the risk of the cancer returning (by about 40% with 5 years of tamoxifen, for example), improving long-term survival (reducing breast cancer mortality by about 30% with 5 years of tamoxifen), and helping to protect the other breast from developing a new cancer.

Like all effective treatments, hormone therapy can have side effects because it changes hormone levels throughout your body. Common side effects can include hot flashes, joint pain (especially with AIs), vaginal dryness, and fatigue; there are also less common but serious risks like blood clots (with tamoxifen) or bone thinning (with AIs) that your doctor will discuss. It's important to know that many of these side effects can be managed with self-care strategies or medical support, so open communication with your healthcare team is key. Sticking to your prescribed treatment plan is crucial for it to be most effective. The decision about which type of hormone therapy to use and for how long should be personalized, made together with your doctor, balancing the benefits against potential side effects and your individual circumstances.

2-2) Chemotherapy 

Understanding chemotherapy in your breast cancer treatment

Chemotherapy, often called "chemo," uses strong medicines to kill cancer cells or stop them from growing. These drugs travel throughout your body, so they can fight cancer cells that may have spread from the breast, even if they are too tiny to see on scans. Chemotherapy works by attacking cells that divide quickly, which cancer cells do much more than most normal cells. This is why it's effective against cancer, but also why it can cause side effects – because some healthy cells (like hair cells or cells lining your mouth) also divide quickly.

Chemotherapy before surgery (neoadjuvant chemotherapy)

Sometimes, your doctor might recommend chemotherapy before breast cancer surgery. This is called neoadjuvant chemotherapy. A major goal is to shrink the tumor in your breast. If the tumor is large, shrinking it can make the surgery easier and might mean you can have a smaller operation, like a lumpectomy (removing just the tumor) instead of a mastectomy (removing the whole breast). Giving chemo first also lets your doctors see how well the cancer responds to the specific drugs, which can help guide future treatment. Neoadjuvant chemotherapy is often considered for larger tumors, inflammatory breast cancer (a rare, aggressive type), or for certain types of breast cancer like triple-negative or HER2-positive breast cancer, as these often respond well to chemo. Most tumors do show some response to this upfront treatment

Chemotherapy after surgery (adjuvant chemotherapy)

More commonly, chemotherapy is given after surgery to remove the breast cancer. This is called adjuvant chemotherapy. Even if your surgery successfully removed all visible cancer, there's a chance some microscopic cancer cells might have been left behind or already spread. Adjuvant chemo aims to kill these hidden cells to lower the risk of the cancer coming back and to improve your chances of long-term survival.[5, 12, 13, 14] Your doctor will consider this if there's a significant risk the cancer could return. Factors that might lead to recommending adjuvant chemo include whether cancer cells were found in your lymph nodes, the size and grade (aggressiveness) of your tumor, and specific features of the cancer cells, like whether they are hormone receptor-positive or HER2-positive.[5, 15] For some hormone receptor-positive, HER2-negative breast cancers, special genomic tests (like Oncotype DX or MammaPrint) on the tumor tissue can help predict your risk of recurrence and whether adding chemo to hormone therapy would be beneficial, helping to personalize your treatment.[16, 17, 18]

The chemotherapy process and side effects

Whether before or after surgery, chemotherapy is usually given in cycles – a period of treatment followed by a rest period to let your body recover. This typically lasts for 3 to 6 months. Common side effects include fatigue, nausea, hair loss, mouth sores, and an increased risk of infection because chemo can affect healthy, rapidly dividing cells. Many of these side effects can be managed with medication and support from your healthcare team, and most go away after treatment finishes. Deciding on chemotherapy involves a detailed discussion with your doctor about the potential benefits for your specific situation versus the possible risks and side effects, always considering your personal preferences.