Consultant Breast and Oncoplastic Surgeon, Dr Tan Gie Hooi explains the causes, types and stages, and risk factors of breast cancer. 

For Life recently interviewed Cheong Yoke Yuen about her experience battling and surviving Stage II breast cancer at 46. In this article, we speak to Yoke Yuen’s friend and doctor, Consultant Breast and Oncoplastic Surgeon, Dr Tan Gie Hooi, who outlines the causes, risk factors, stages and subtypes of breast cancer, including how women can reduce their risk of the disease.

Causes and risk factors or breast cancer

Breast cancer is the most common form of cancer among Malaysian women, affecting as many as one in 19 women locally.

According to Dr Tan, who practices at the Thomson Hospital, breast cancer is a multifactorial condition caused by genetic and environmental factors.

Although a genetic predisposition may increase one’s chances for breast cancer, only 5 to 10% of patients have a family history of the disease, which means that a majority of cases are sporadic and/or exacerbated by environmental influences.

Environmental risk factors for breast cancer are divided into modifiable and non-modifiable risk factors. Non-modifiable risk factors are those which patients cannot control, including advanced age, being female, breast density, and the age in which women menstruate and experience menopause.

“Studies show that the denser the breasts and the older the patient, the higher the risk of cancer. Women who have their first period early (before 12) and who experience menopause late (after 55) also have an increased risk as they have a longer lifetime of menstrual bleeding, which in turn, exposes the breasts to a longer lifetime of oestrogen changes,” says Dr Tan.

Modifiable risk factors, however, are lifestyle related. In addition to smoking and obesity, other modifiable risk factors for breast cancer are; being nulliparous (having no children), having children later than 30, and long-term use of oral contraceptives and hormone replacement therapy for more than five years.

“In Yoke Yuen’s case, although she had no family history of the disease, she is nulliparous which potentially increased her chance for breast cancer. This would mean she would not have breastfed, which, in contrast, could have reduced her risk.”

Stages and types of cancer and treatment

There are four stages of breast cancer. These include:

Stage 1: When the cancer is less than 2cm in diameter and has invaded normal breast tissues but has not spread to the lymph nodes.

Stage 2: When the cancer has already affected the lymph nodes

Stage 3: When the tumour is 5cm in diameter and/or when a higher number of lymph nodes are affected

Stage 4: When the cancer has spread to distant organs of the body, usually the brain, lungs, bones, or liver. At this stage, treatments are no longer curative but palliative to improve patients’ quality of life.

According to Dr Tan, while breast cancer doesn’t advance from Stage I to the next overnight, the rate of progression depends on the tumour’s grade and cancer sub-type, which can only be ascertained after the tumour is examined under a microscope, following a biopsy.

“Tumour grades are divided into, Grade 1: when tumour cells closely resemble normal cells, Grade 2: when cells relatively resemble normal cells and Grade 3: when they look highly abnormal to normal cells. Grade 3 cells are usually the most fast-growing and aggressive.”

Breast cancer sub-types are determined by the genes they express. These include being hormone-receptor (estrogen and/or progesterone) positive or negative and HER2-receptor positive or negative. Approximately two out of three breast cancers are hormone-receptor positive, while only 20% of patients test positive for HER-2 . In most cases, patients who test positive for hormone-receptor breast cancer alone, have low-grade cancer and a better prognosis, while those who test positive for HER-2, have faster growing cancer cells and a more aggressive form of disease. Patients who test negative for all three receptors (oestrogen, progesterone and HER-2), otherwise known as triple-negative breast cancer, have the most aggressive disease and the worst survival rate of the various breast cancer subtypes.

Once a patient’s cancer type and stage of disease are confirmed, these will determine his or her treatment plan moving forward.

“In Yoke Yuen’s case, her pathology report concluded that she had Stage II breast cancer, which was oestrogen and HER-2 positive. This was why she underwent a mastectomy to remove the affected breast, chemotherapy and radiation to kill the cancer cells in the lymph nodes, and targeted Herceptin therapy, which binds to HER-2 receptors on the surface of cancer cells to destroy and/or stop them from growing. Yoke Yuen was also put on long-term hormone medications, which she still uses to this day, to control the body’s oestrogen production and reduce the likelihood of cancer recurring.”

Dr Tan Gie Hooi, Consultant Breast and Oncoplastic Surgeon

How can women check for signs and symptoms of breast cancer?

According to Dr Tan, women can check for signs and symptoms of breast cancer at home by paying attention to the breasts’ visible and palpable changes. Visible changes can include nipple retraction, nipple discharge, scaliness, redness and thickening of the nipple or breast skin, and skin irritation or dimpling. Palpable changes involve feeling for hard, nut-sized lumps that are fixed/immobile under the skin.

“If you notice any of these changes, visit a doctor immediately. I also suggest avoiding feeling for lumps right before your menses as this is when the breasts are most congested.”

How can women reduce their risk of breast cancer?

Women can reduce their risk of breast cancer by reducing their modifiable risk factors. These include, maintaining an ideal body weight, reducing alcohol consumption, avoiding nicotine and having children earlier in life. Breastfeeding for at least a year and avoiding long-term use of oral contraceptives and hormone-replacement medications can also help.

In addition to these lifestyle changes, Dr Tan emphasizes the importance of undergoing annual breast screenings because early detection allows doctors to catch the disease at its early stages. This, in turn, results in a better prognosis and overall survival rate.

“Women with a family history of breast cancer should start having yearly mammograms 10 years before their family members were diagnosed with the disease. If you have an average risk, guidelines recommend that women undergo annual mammograms from age 40 to 59. Thereafter, one mammogram every one to two years should suffice.


Feature image courtesy of Cheong Yoke Yuen.
Dr Tan image courtesy of Dr Tan Gie Hooi.

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