BACKGROUNDER                                                                           

EMBARGOED: WED, NOVEMBER 25, 2015

                 

 

About breast cancer

 

ABOUT BREAST CANCER

• Breast cancer occurs when the cells lining the breast lobules or ducts grow abnormally and out of control, which can lead to the formation of tumours in the lobules or ducts of the breast.1

• Breast cancer is not one disease. There are several types and sub-types of breast cancer which include:

• Non-invasive breast cancers: Often referred to as pre-cancers, non-invasive breast cancers grow in the milk ducts or lobules in the breast.2

• Ductal carcinoma in situ (DCIS): Contained in the milk ducts of the breast, DCIS is the most common, non-invasive form of breast cancer.2 While not life-threatening, DCIS does increase the risk of invasive breast cancers later in life.2

• Lobular carcinoma in situ (LCIS): Non-invasive cancer that grows in the milk-producing glands (lobules).2 Like DCIS, LCIS is not life-threatening, but increases the risk of developing invasive breast cancer later on.2

• Invasive breast cancers: These are the cancers that grow outside of the milk ducts, in the normal, healthy breast tissue.2

• Early breast cancer: Usually limited to the breast tissue, however some early breast cancers might have moved into the lymph nodes in the breast or arm tissue, but no further.2

• Paget’s disease of the nipple: Also referred to as Paget’s disease of the breast, this is a rare form of invasive breast cancer in which cancer cells grow in the nipple or areola.2 Paget’s disease of the breast is often associated with more than one tumour in the breast.3

• Inflammatory breast cancer (IBC): Making up between 1-2 per cent of total breast cancer diagnosis, IBC is an extremely rare form of invasive breast cancer.4 IBC spreads rapidly along the blocks and lymph vessels in the skin of the breast. When the lymph vessels are blocked they inflame, becoming red and swollen.4

• Locally advanced breast cancer: An invasive form of breast cancer that has spread beyond the breast to other nearby areas of the body such as the skin, chest wall, chest muscle, or more extensively throughout the lymph nodes.2

• Secondary or metastatic breast cancer: Also known as stage-4 breast cancer, this form of cancer has spread to other parts of the body; most commonly to the bones, liver or lungs.2 Although a cure for secondary breast cancer has not yet been found, recent advances in treatment mean it can be controlled for extended periods of time.5

• Another way of defining or categorising breast cancer is through tumour pathology, which breaks breast cancer down into three sub-classifications:

• Hormone receptor positive,

• HER2-positive, or

• Triple negative.2

 

HORMONE RECEPTOR POSITIVE BREAST CANCER

• About two-thirds of breast cancers are hormone receptor positive,6 which means they require female hormones (oestrogen and/or progesterone) to grow and reproduce.6

• The most commonly recommended treatment for hormone positive breast cancer is hormone therapy, using oral medications such as tamoxifen and the aromatase inhibitors, anastrozole and letrozole that are taken daily for a minimum of five years, following the completion of breast cancer treatments (surgery, chemotherapy, radiotherapy).6

 

HER2-POSITIVE BREAST CANCER

• This form of breast cancer tests positive for too much of a protein called human epidermal growth factor receptor 2 (HER2). 7,8

• Healthy HER2 receptors are proteins in the breast that manage cell growth, division and reparation. In HER2-positive breast cancer, the malfunctioning HER2 gene produces an excess of protein, which promotes the growth of cancer cells. 7,8                     

• About one in five women have HER2-positive cancer cells. Trastuzumab in combination with chemotherapy, is the most common treatment recommended for HER2-positive breast cancer.9             

          

TRIPLE-NEGATIVE BEAST CANCER

• Around 15 per cent of breast cancers are triple-negative breast cancers.10

• Triple-negative breast cancers do not have any of the three receptors – oestrogen, progesterone or HER2 – which are commonly found in breast cancer cells. 10

• Risk factors for triple-negative breast cancer include being premenopausal*10, having BRCA mutations that prevent the BRCA1 and BRCA2 genes (these act as tumor suppressor proteins), from functioning correctly, which can result in tumour growth. 10,11

*Premenopausal women have a higher rate of triple negative breast cancer than postmenopausal women. Scientists do not yet understand why this is the case, however research is currently underway in this area.

 

INCIDENCE AND MORTALITY OF BREAST CANCER IN AUSTRALIA

• In 2010, breast cancer was the most common cancer in Australian women (excluding non-melanoma skin cancer), responsible for 20 per cent of all new cancers in women.12,13

• The risk of developing breast cancer increases with age.14,15

• 69 per cent of breast cancers are diagnosed in women between the ages of 40-69, while 25 per cent are diagnosed in women aged 70 and older.15

• In 2011, 14,465 women and 103 men were diagnosed with breast cancer in Australia.16

• In 2012, 2,795 women and 24 men died from breast cancer in Australia.16

• 12.5 per cent of Australian women will develop breast cancer before the age of 85.12

• Breast cancer is much more uncommon in males than in females, with a very small number (1-in-917) of men diagnosed with breast cancer before the age of 85.16

• In 2014, an estimated 15,270 Australian women were diagnosed with breast cancer.14

• In 2020, it is estimated there will be 17,210 new cases of breast cancer diagnosed in women.14

 

SYMPTOMS, RISK FACTORS OF BREAST CANCER

The causes of breast cancer are unknown, but risk factors include:

• Increasing age;

• Family history;

• Inheritance of genetic mutations, including BRCA2, BRCA1 and CHEK2;

• Exposure to female hormones (natural and administered);

• Obesity; and

• Excess alcohol consumption.16

 

Symptoms of breast cancer include, but are not limited to:

• New lumps or thickening in the breast or under the arm;

• Nipple sores;

• Nipple discharge or turning in;

• Dimpling or pulling of the skin on the breast; and

• Rash or red swollen breasts.16

 

DIAGNOSIS

Due to the varying types and sizes of breast cancers, there are several tests that can lead to diagnosis, including:

• Physical examination: A doctor will examine the patient’s breasts and lymph nodes under the arms, feeling for any lumps or irregularities. They will take a full medical history and family history.9

• Mammogram: A low-dose X-ray of the breast tissue. Not all changes are large enough to be felt during a physical examination, so through a mammogram examination, doctors can identify these small changes. During a mammogram, the patient’s breast is pressed between two plates, spreading the breast tissue, so that clear pictures can be taken.9

• If your GP feels a lump during the physical examination, which is not present on a mammogram, other tests may be required.9

• Ultrasound: A painless procedure in which sound waves are used to create a picture/scan of your body. To conduct an ultrasound, the therapist spreads a gel on the patient’s breast, while moving a transducer probe over the area. This sends out sound waves that echo when they meet something dense, like an organ or tumour. This data appears as an image on a computer screen.9

• Breast MRI: Breast MRI (magnetic resonance imaging) is more sensitive than mammography or breast ultrasound, and is commonly used to screen women at high-risk of breast cancer. Breast MRI is also used in women with very dense breast tissue.9

• Patients undergoing breast MRI may be injected with a contrast dye that make any potential

• Biopsy: During a biopsy, a small amount of tissue is removed from the patient’s breast. The tissue will then be provided to a pathologist for examination, who will outline their findings, which include the size and location of the tumour, the grade of the cancer, whether there are cancer cells close to the edge of the breast tissue, and whether there are cancer cells in the patient’s lymph nodes in their pathology report, helping the treating physician to determine the best treatment approach.9

• There are multiple forms of biopsy, including:

• Fine needle aspiration (FNA);

• Core biopsy;

• Vacuum-assisted stereotactic biopsy (VAB); and

• Surgical biopsy.9

• cancerous breast tissue more visible.9

 

 

CAN BREAST CANCER BE TREATED?

• Anti-oestrogen, aromatase inhibitors, ovarian suppression and progesterone medicines are commonly used hormone therapy treatments for breast cancer.6

• Anti-oestrogen medicines can be used to treat pre and post-menopausal women,6 while aromatase-inhibiting medicines can only be used in post-menopausal women.6

• Hormone therapy treatments work to prevent oestrogen ‘feeding’ breast cancer cells.6

• Side-effects of hormone therapy include menopausal symptoms, hot flushes, night sweats, heart palpitations, anxiety, sleep disturbance and fatigue.6

• Two of the most commonly prescribed hormone therapy treatments for hormone receptor positive breast cancer include:

• Anastrozole: A non-steroidal aromatase inhibitor therapy, which works by reducing the body’s oestrogen levels. Anastrozole is used to treat breast cancer in women who no longer have a menstrual period following surgery, radiotherapy, chemotherapy, or natural ageing. By blocking the production of oestrogen, Anastrozole may delay, or prevent cancer growth. 17

• Letrozole: Similar to anastrozole, letrozole is an oral aromatase inhibiting medicine, which works to reduce the production of oestrogen. Letrozole is used to treat breast cancer in post-menopausal women.18

• In Australia, HER2-positive breast cancers are treated using the monoclonal antibody medicine, trastuzumab,19 or biological medicine, lapatinib.20

• For women with HER2-positive early breast cancer, trastuzumab is given in combination with chemotherapy, and usually following breast cancer surgery.19

• For women with HER2-positive secondary breast cancer, trastuzumab may be given on its own, or in combination with chemotherapy, or other medicines.19

• The biologic, lapatinib is often recommended to women with secondary HER2-positive cancer that has stopped responding to a combination of trastuzumab and chemotherapy.20 Lapatinib is an oral medicine usually taken as part of a combination treatment with chemotherapy medicine, capecitabine.20

• Triple-negative breast cancer is treated using chemotherapy, and is usually very responsive to chemotherapy treatment.6

 

SIDE EFFECTS ASSOCIATED WITH BREAST CANCER THERAPIES

• All medicines can have side-effects. Sometimes they are serious, most of the time they are not. Side-effects may occur with the commencement of treatment or after you have been on your treatment for some time.17,18

• Some common side-effects of aromatase inhibiting medicines include pain, joint stiffness, vaginal dryness and loss of bone density in post-menopausal women.6, 17, 18

• If you are concerned about side-effects associated with breast cancer therapies, talk to your doctor promptly.

 

MEDIA CONTACTS

Kirsten Bruce, 0401 717 566; Ruby Archis, 0413 834 906;

Mark Henderson, 0431 465 004

REFERENCES

1. American Cancer Society - What is Breast Cancer? - [Accessed July 2015].

2. Breast Cancer Network Australia – Understanding Breast Cancer - [Accessed July 2015].

3. National Cancer Institute – Paget’s Disease of the Breast -  [Accessed July 2015].

4. Cancer Australia – Information About: Inflammatory Breast Cancer, April 2007. National Breast Cancer Screening Centre - [Accessed July 2015].

5. Breast Cancer Network Australia – Understanding breast cancer - What is secondary breast cancer? - [Accessed July 2015].

6. Breast Cancer Network Australia – Understanding Breast Cancer – Hormone Therapy - [Accessed July 2015].

7. National Breast Cancer Foundation, INC – Abut Breast Cancer – Lab Tests - [Accessed July 2015].

8. Breastcancer.org  - HER2 Status - [Accessed July 2015].

9. Cancer Council Australia – Tests to diagnose breast cancer - [Accessed July 2015].

10. Breast Cancer Network Australia – Understanding Breast Cancer – Triple Negative Breast Cancer - [Accessed July 2015].

11. National Cancer Institute – BRCA1 and BRCA2: Cancer Risk and Genetic Testing - [Accessed July 2015].

12. Australian Cancer Incidence and Mortality (ACIM) Books - Breast cancer for Australia (ICD10 C50).   [Accessed July 2015].

13. Australian Cancer Incidence and Mortality (ACIM) Books – All Cancers combined for Australia (ICD10 C00-C97, D45-46, D47.1, D47.3).   [Accessed July 2015].

14. Cancer Australia – Breast Cancer Statistics - - Australian Government [Accessed July 2015].

15. Australian Institute of Health and Welfare & Cancer Australia 2012. Breast cancer in Australia: an overview. Cancer series no. 71. Cat no. CAN 67. Canberra: AIHW.

16. Cancer Council Australia – Breast Cancer - [Accessed July 2015].

17. Anastrozole FBM – Consumer Medicine Information - [Accessed July 2015].

18. Letrozole FBM – Consumer Medicine Information - [Accessed July 2015].

19. Cancer Australia – Breast Cancer – Types of Targeted Therapy – Trastuzumab - [Accessed July 2015].

20. Cancer Australia – Breast Cancer – Types of Targeted Therapy – Lapatinib distosylate - [Accessed July 2015].