Breast cancer incidence has been steadily increasing over the past few decades in Asia, according to data from the Institute for Health Metrics and Evaluation (IHME), due to various environmental, demographic, and reproductive factors. It ranks as the most common malignancy in females in most countries. The lifetime risk of breast cancer is as high as 1 in 8 in the US.
In Thailand, breast cancer incidence has increased over the past 20 years and is now the number one female cancer with an age-standardised rate of 28.5 cases per 100,000 person-years.
Diagnosis
Medical imaging with a mammogram, breast ultrasound, or MRI can diagnose suspicious lesions. But the only definitive way to make a diagnosis is a breast biopsy. Typically, a core of tissue is removed with a special needle guided by an X-ray or other appropriate imaging equipment for pathological tissue diagnosis.
Treatments
The treatments of breast cancer depend on the stage at presentation. Patients are stratified into broad categories of early stage and locally advanced. 5% or more will have metastatic disease at initial presentation.
Patients with early-stage breast cancer undergo primary surgery (lumpectomy or mastectomy) to the breast and regional nodes with or without radiation therapy (RT).
In addition to surgery and radiation therapy which are local treatment modalities, supplemental treatment with systemic treatment before or after surgery, termed adjuvant therapies, may be offered in appropriate cases. Assessment is based on primary tumour characteristics such as tumour size, grade, number of involved lymph nodes, the status of estrogen (ER) and progesterone (PR) receptors, and expression of the human epidermal growth factor 2 (HER2) receptor.
Surgery
Surgery is the central pillar of breast cancer treatment. For early-stage breast cancers, it could be the only treatment required. Breast cancer surgery consists of two components – surgery of the breast and the dissection of lymph nodes in the armpit.
It is beneficial for cancer control and yields pathological examination of the excised breast tissue revealing the actual cancer grade and stage to guide the appropriate treatment plan and prognosis.
Surgery of the breast proper
Removal of the entire breast (including the nipple and skin over the tumour) was a standard surgical procedure. However, it is now mainly for patients with a large primary cancer, multiple primary tumours, patients not amenable to breast-conserving surgery, or those at risk of cancer recurrence or unable to undergo radiation therapy after surgery.
Partial mastectomy or breast-conserving surgery is the excision of the tumour with a 1-2 cm. margin of uninvolved surrounding tissues, sparing the nipple, areola, and most of the remaining breast. This surgery is suitable for patients with a single, small tumour in a sizable breast. Postoperative radiation therapy is mandatory for every patient. Partial mastectomy is as good as total mastectomy, retaining the shape of the breast near its natural state.
Surgery of the axillary lymph nodes
The risk for metastases to the axillary nodes is related to tumour size and location, histologic grade, and the presence of lymphatic invasion within the primary tumour. The metastatic spread of primary breast cancers follows a predictable pattern to the first group of axillary lymph nodes, called sentinel lymph nodes, before involving other axillary nodes and beyond. Therefore, if the sentinel lymph nodes are free of metastatic cancer, the remaining axillary lymph nodes can be left untouched. Sentinel lymph node biopsy is routinely performed except for those with clinically palpable abnormal lymph nodes, particularly when associated with a large primary tumour. Axillary dissection can cause complications such as numbness in the upper inner arm, nerve injury affecting the function of some muscles, or long-term swelling of the arm and frozen shoulder.
Ancillary procedures such as breast reconstructive surgery are not the primary cancer treatment but can substantially enhance a patient's quality of life. Since breast cancer treatments are more effective, patients now live longer with less chance of recurrence, especially those with early-stage cancer. In addition to saving the patient's life, conserving and retaining the breast configuration is of value to build confidence, dial down the psychological effect of gender-defining organ loss and improve the postoperative quality of life. Breast reconstruction rebuilds the breast with transposed tissue from other body areas or breast prostheses without adverse effects on the breast cancer treatment outcome. It helps patients regain confidence in returning to work and resuming their daily life. The reconstruction can be immediate or delayed.
Radiation Therapy
For breast cancer patients, radiation therapy is given after breast-conserving surgery or used as an adjuvant treatment for patients after total mastectomy with unfavourable features, i.e., tumours larger than 5 cm, cancer involvement of the skin or the chest muscles, and those with extensive axillary lymph nodes metastasis.
Chemotherapy
Chemotherapy is a form of systemic treatment; it enhances the chance of a cure. Multiple drugs are given concurrently in cycles lasting 3 to 4 weeks for better efficacy with a rest period for recovery of affected normal, fast-dividing cells. Side effects are common, but medications can pre-emptively forestall them. In women of reproductive age, contraception is crucial to preclude the teratogenic effects of chemotherapy on the foetus born of an unexpected pregnancy.
Hormonal Therapy
Breast growth and function are hormone-dependent, and so are the proliferation of many breast cancers. In Thailand, 2 out of 3 breast cancer patients respond to anti-hormone therapy. The determination of hormone-responsive breast cancer is by special tissue staining for the presence of oestrogen and progesterone hormone receptors. If the cancer is hormone-receptor-positive, it will be responsive to anti-hormone therapy. The management of hormonal treatment is easy and convenient because they are oral medications. Patients will take the drugs for 5-10 consecutive years. They cause minimal, mild side effects.
Targeted therapy
With a better understanding of the fundamental biology of cancer, researchers have identified specific molecular targets of cancer cells that are unique to cancer cells or differ substantially from normal cells. Anti-HER2 is one of the early members of this new class of targeted drugs with a mechanism of action more specific than chemotherapeutic drugs on cancer cells. Cancerous breast cells in some patients overexpress HER2 receptors on the cell membrane surface, enabling anti-HER2 to detect and bind to the receptors and kill the cancer cells. Cells not expressing HER2 receptors will not be affected. Though this targeted therapy is very effective with fewer side effects, it has limitations. A minority of breast cancer patients exhibit HER2 receptors, and the price is exceedingly high. Therefore, this targeted therapy is not widely applicable.
Chemotherapy, hormonal, and targeted therapy may be given as adjuvant treatment before or after surgery, depending on the characteristics and stage of the tumour at presentation.
Detection of breast cancers in the early stages simplifies the treatment process and favourably influences the treatment outcome. Every woman should have regular breast cancer screening before signs or symptoms of the disease develop. Discuss with a health care provider or a breast specialist regarding your best breast cancer screening option.
Author: Prof. Dr. Pornchai O-Charoenrat, Breast Surgeon, MedPark Hospital. For further details email: access@medparkhospital.com
Series Editor: Katalya Bruton, Healthcare Content Editor, Dataconsult Ltd. Dataconsult's Thailand Regional Forum at Sasin provides seminars and documentation to update business on trends in Thailand and the Mekong Region. Contact: info@dataconsult.co.th
