1.1 Breast cancer in Hong Kong
Since 1994, breast cancer has become the most common cancer among women in Hong Kong, with over four thousand new cases diagnosed each year. According to statistics, approximately one out of every fourteen women will experience breast cancer at some point in their lifetime.
The majority of breast cancer cases occur in middle-aged women, with the median age of diagnosis in Hong Kong being around 62 years old. About half of the breast cancer cases in Hong Kong occur in women aged 40 to 59. Generally, the older the age, the higher the risk.
Breast cancer is also the third leading cause of cancer-related deaths among women in Hong Kong, with over 700 deaths reported annually, and a mortality rate of approximately 18%. Some breast cancer patients are diagnosed with lymph node or distant organ metastasis, which indicates a poorer prognosis. These patients may only have the option of palliative treatment to prolong their lives. Therefore, it is crucial for anyone who suspects symptoms related to breast cancer to seek medical attention early, undergo relevant examinations, identify the cause, and receive timely diagnosis and treatment, as early detection and treatment are vital for a successful recovery from breast cancer.
1.2 What is breast cancer?
The development of breast cancer is primarily caused by genetic mutations in the cells of the breast tissue, leading to uncontrolled growth and division, ultimately forming malignant tumors, which are known as breast cancer.
Breast cancer tumors not only continue to grow and increase in size but also invade and destroy the surrounding normal breast tissue, resulting in clinical symptoms. Over time, cancer cells can spread through the lymphatic system to the lymph nodes in the armpit, and even through the bloodstream to distant organs (most commonly the lungs, bones, liver, brain, etc.). If distant organ metastasis is already present at the time of diagnosis, the tumor is generally not curable through surgical means, and the prognosis is considerably poor.
1.3 Cause of breast cancer
Currently, there is no definitive consensus on the exact causes of breast cancer in medical science. However, based on previous research data, certain risk factors have been identified that are closely associated with breast cancer. Some of these risk factors are non-modifiable, including personal medical history, family history, and age. Additionally, breast cancer is directly related to the secretion of female hormones in the body, so any factors that increase the levels of female hormones can also increase the risk of developing breast cancer, such as the use of contraceptive pills, being overweight, and never having breastfed.
Non-modifiable risk factors:
- Family history of breast cancer, especially among close relatives
- Age
- Genetic factors
- Early onset of menstruation (before the age of 12) or late menopause (after the age of 55)
- Personal history of breast cancer
- Previous diagnosis of certain benign breast conditions
Modifiable risk factors:
- Alcohol consumption
- Smoking
- Never having breastfed
- Never giving birth or first pregnancy after the age of 35
- Use of contraceptive pills
- Use of hormone replacement therapy
- Being overweight
- Lack of physical exercise
Possible risk factors:
- Night shift work
- Psychological stress
- Excessive consumption of meat/dairy products
1.4 Symptoms of breast cancer
Early-stage breast cancer may not have obvious symptoms or may even be completely asymptomatic. Some patients only discover their breast cancer incidentally during breast cancer screening.
The presence of a palpable lump in the breast is an important sign of breast cancer, especially if the lump is painless or if there is localized hardening of the breast. Common symptoms of breast cancer include:
- Painless lump in the breast
- Firm and irregularly shaped lump in the breast
- Fixed lump in the breast that cannot be easily moved
- Unclear or irregular borders of the lump
- Indentation or dimpling of the skin over the breast
- Skin redness, swelling, or ulceration on the breast
- Nipple retraction or inversion
- Abnormal nipple discharge, possibly with blood
- Enlarged lymph nodes in the armpit
- Breast pain
- Noticeable weight loss and loss of appetite
It is important to note that these symptoms can also be caused by conditions other than breast cancer. If any of these symptoms are present, it is advisable to seek medical attention for further evaluation and diagnosis.
1.5 Types of breast cancer
Breast cancer can be further classified based on pathological features and tumor invasiveness, and different types of breast cancer tumors have distinct clinical characteristics and prognoses. Breast cancer can generally be divided into two categories:
Invasive Breast Cancer
Invasive breast cancer refers to cancer cells that have invaded the surrounding tissues outside the breast ducts or lobules. The most common type is invasive ductal carcinoma. Invasive breast cancer has the potential to spread through the lymphatic system to the axillary lymph nodes or through the bloodstream to distant organs.
In Situ Carcinoma
In situ carcinoma refers to cancer cells that have not yet invaded beyond the breast ducts or lobules and is also known as stage 0 breast cancer. The most common type is ductal carcinoma in situ (DCIS). In situ carcinoma does not spread through the lymphatic or blood vessels to other parts of the body, so the prognosis for this type of cancer is generally better than invasive cancer.
It’s important to note that the classification and subtypes of breast cancer can be more complex, involving additional factors such as hormone receptor status (estrogen and progesterone receptors) and human epidermal growth factor receptor 2 (HER2) status. Further diagnostic tests and evaluations are necessary to determine the specific subtype and guide appropriate treatment options.
1.6 How to diagnose breast cancer?
Please refer to → Diagnosis of Breast Cancer ← Page
1.7 Staging of breast cancer
The purpose of staging breast cancer is to determine the appropriate treatment plan, predict prognosis, and assess the risk of recurrence based on the clinical characteristics of the tumor. The most commonly used staging system for breast cancer is the UICC/AJCC staging system, also known as the TNM staging system. This staging system classifies breast cancer tumors into stages I to IV based on factors such as tumor size (T), lymph node involvement (N), and distant metastasis (M).
Stage I tumors have the highest cure rate and the best prognosis, while stage IV tumors have the lowest cure rate and the worst prognosis.
T staging depends on the size of the tumor and whether it has invaded surrounding tissues. T1 tumors have a diameter of less than 2cm, T2 tumors have a diameter between 2-5cm, and T3 tumors have a diameter larger than 5cm. T4 indicates clinical signs of tumor invasion into the skin (T4a), chest wall (T4b), or both (T4c). T4d refers to tumor invasion into the lymphatic layer beneath the skin, causing breast redness, swelling, and peau d’orange appearance.
N staging refers to the presence or absence of lymph node involvement, specifically in the axillary or internal mammary lymph nodes.
M staging indicates whether the tumor has spread to distant organs through the bloodstream. The most common sites of distant metastasis include the lungs, liver, brain, and bones.
The staging system helps guide treatment decisions and provides important prognostic information, allowing healthcare professionals to tailor treatment plans to individual patients and monitor their progress.
1.8 Treatment of breast cancer
1.8 How to prevent breast cancer?
Due to the complex factors influencing the development of breast cancer, there are currently no definitive methods to prevent breast cancer. However, maintaining a healthy lifestyle and adopting healthy dietary habits can certainly reduce the risk of developing breast cancer.
Lifestyle habits
- Quit smoking and limit alcohol consumption: Smoking and excessive alcohol intake increase the risk of breast cancer. Additionally, smoking and alcohol consumption have adverse effects on our cardiovascular system.
- Maintain a healthy weight: Being overweight increases the chances of developing breast cancer. The current recommendation is for adults to maintain a body mass index (BMI) between 18.5 and 25.
- Engage in regular physical activity: Engaging in at least 4 hours of moderate exercise per week can effectively reduce the risk of breast cancer.
- Manage stress: Psychological stress can increase the secretion of stress hormones (cortisol) and weaken the immune system. Therefore, it is important to learn how to actively and positively cope with stress. If you feel overwhelmed, seek assistance proactively.
Healthy diet
- Consume a plant-based diet: Eating five or more servings of fruits and vegetables daily can reduce the risk of breast cancer.
- Additionally, it is recommended to limit the intake of saturated animal fats found in red meat and full-fat dairy products, as they are associated with various types of cancer, including breast cancer.
- Cruciferous vegetables such as broccoli, cauliflower, and kale are effective in reducing estrogen levels, thus lowering the risk of breast cancer.
- Whole grains, such as bread, rice, oats, and pasta, can reduce estrogen levels in the blood and decrease the risk of breast cancer.
- Olive oil and omega-3 fatty acids can effectively reduce the risk of breast cancer.
- Consume antioxidant-rich foods: Antioxidant-rich foods containing ample amounts of vitamin C, vitamin E, and carotenoids help combat free radicals. These foods include blueberries, raspberries, strawberries, broccoli, spinach, Brussels sprouts, and red peppers.
- Green tea, which contains antioxidant polyphenols, has anticancer properties.
Ensure adequate intake of vitamin D and calcium.
Regular breast examination and breast cancer screening
If you notice any abnormalities in your breasts, seek medical attention immediately. Regular breast self-examination and breast cancer screening are important for early detection and prompt treatment if necessary.