Breast cancer is one of the most common cancers among women in Hong Kong, with a noticeable trend towards younger onset in recent years. This has raised concerns among many ladies regarding their personal risks and available treatment options. Clinical oncologist Dr. Lee Wai Man Sarah explains that understanding breast cancer risk factors, classification methods, and the latest treatment directions can help patients grasp their condition early and select the most suitable personalised treatment plan.

Current Situation of Breast Cancer in Hong Kong and the Younger Onset Trend

According to Dr. Lee Wai Man Sarah, breast cancer has a high incidence rate in Hong Kong, with an average of over 5,500 new cases each year. Approximately 1 in 13 women may develop breast cancer. While the typical age of onset is around 60, there has been a clear trend of younger onset recently, with more cases among women in their 40s. Dr. Lee notes that Hong Kong women generally place great importance on health and tend to undergo breast examinations and imaging earlier, allowing many cases to be detected at an early stage.

Causes of Breast Cancer and High-Risk Groups

Breast cancer has multiple causes. Apart from increasing age, hormone levels play a significant role; for example, early menarche or late menopause can increase the risk. A strong family history, especially among first-degree female relatives with cancer or breast cancer, further elevates the risk. Some patients may even have hereditary gene mutations, such as BRCA1 or BRCA2 mutations, which can raise the lifetime risk to over 50%. Dr. Lee Wai Man Sarah recommends that if family history suggests hereditary risk, genetic testing and screening should be conducted early for timely monitoring.

Breast Cancer Classification: The Foundation of Personalised Treatment

Why is breast cancer divided into different categories? Dr. Lee Wai Man Sarah explains that modern medicine emphasises personalised treatment. Different types of breast cancer have distinctly different prognoses and treatment directions. Doctors mainly classify breast cancer by examining three types of receptors on the surface of cancer cells: hormone receptors (ER and PR) and HER2 receptor.

• Hormone receptor positive: Suitable for hormone therapy.
• HER2 receptor positive: In addition to traditional chemotherapy, targeted therapy can be added.
• Triple-negative breast cancer (all three receptors negative): Cancer cells grow faster and spread more easily; treatment often involves stronger chemotherapy or the addition of immunotherapy.

Dr. Lee emphasises that subdividing categories is not because certain types are difficult to treat, but to select the most appropriate drugs based on the patient’s actual condition, thereby increasing the chance of cure.

New Classification: HER2-low Breast Cancer

In recent years, the medical community has introduced a new category called HER2-low (HER2 weakly positive). Traditional HER2 testing uses immunohistochemistry (IHC) scoring from 0 to 3 points; a score of 2 requires further confirmation with in situ hybridisation (ISH) technology. Cases with expression levels between negative and positive are classified as HER2-low. Although HER2 expression in these patients is slightly lower than traditional positive cases but higher than completely negative ones, some patients with advanced breast cancer can now use targeted drugs originally intended for HER2-positive cases, bringing new treatment options.

New Treatment Directions for Advanced HER2 Breast Cancer

For HER2-positive breast cancer, traditional treatment includes chemotherapy combined with targeted drugs. A newer treatment direction that has emerged recently is antibody-drug conjugate (ADC). Dr. Lee Wai Man Sarah describes ADC as a “biological missile”: the targeted drug first precisely identifies and binds to the HER2 receptor on cancer cells, then releases chemotherapy drugs directly into the cancer cells to accurately kill them while reducing impact on normal cells. This new direction offers more effective treatment choices for patients with advanced HER2 breast cancer.

 

Although breast cancer is common, early screening, understanding personal risks, and receiving personalised treatment can greatly improve the chances of cure. Dr. Lee Wai Man reminds that every patient’s condition and treatment plan is different and must be determined by the doctor based on detailed diagnosis. If you have any questions about breast cancer risk, classification, or treatment, it is advisable to consult your attending clinical oncologist as soon as possible for professional assessment and formulation of a personalised treatment plan.

 

 

More information about breast cancer: Early Breast Cancer Signs & Causes | OncoCare

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Frequently Asked Questions Q&A

Q1: Is breast cancer common in Hong Kong? Is there a trend towards younger onset?

A: Breast cancer is one of the most common cancers in Hong Kong women, with over 5,500 new cases annually. Approximately 1 in 13 women may develop it. The typical onset age is around 60, but cases among women in their 40s have increased recently, showing a younger onset trend.

Q2: What are the main causes and high-risk factors for breast cancer?

A: Causes include increasing age, hormone levels (such as early menarche or late menopause), strong family history, and BRCA1/BRCA2 gene mutations. Risk increases with first-degree relatives having breast cancer, and hereditary cases can exceed 50% lifetime risk.

Q3: Why does breast cancer need to be subdivided into different categories?

A: Subdivision enables personalised treatment. Different categories have different prognoses and suitable drugs. Doctors select the most targeted treatment based on ER, PR, and HER2 receptor status to improve cure rates.

Q4: What is HER2-low breast cancer and what makes it special?

A: HER2-low is a new classification for cases where HER2 expression falls between negative and positive. Some of these patients can use targeted drugs originally for HER2-positive cases, providing more treatment options for advanced patients.

Q5: What new treatments are available for advanced HER2 breast cancer?

A: In addition to traditional chemotherapy plus targeted therapy, antibody-drug conjugate (ADC) has emerged recently. It acts like a biological missile, precisely delivering chemotherapy into cancer cells to kill them effectively.

Q6: How should women with family history prevent or monitor breast cancer?

A: If family history indicates hereditary risk, early genetic testing and breast screening are recommended. Dr. Lee Wai Man Sarah reminds that early detection helps improve treatment outcomes.