Carcinoma of the Breast

3D Animation on Breast Cancer This animation brought to you by Blausen Medical Communications. Contact Andrew Walbank. Carcinoma of the breast is the malignant proliferation of the cells of the breast. The vast majority of these carcinomas involve the cells of the ducts or lobules of the breast.2

Breast cancer is predominantly a disease of women. Of the total number of new cases of breast cancer diagnosed each year, less than 1% of affected patients are men.¹ In Australian women, breast cancer is the most frequently diagnosed type of invasive cancer. It is also the leading cause of cancer death in Australian females.¹

The incidence of breast cancer increases with age. The disease is rare under the age of 30, but by 75 years of age as many as 1 in 11 women will have received a diagnosis of breast cancer. The average age at diagnosis is 60 years.¹ The age-standardised incidence of breast cancer in Australia is similar to that in other developed countries such as Canada and the United Kingdom, and is lower than that of the United States of America and New Zealand.¹

The main risk factors for adenocarcinoma of the breast are:

• Increasing age;
• A family history of breast cancer;
• Hormonal factors: women who begin menstruation early, have a late menopause, or have late or few pregnancies;
• Obesity;
• Excess alcohol use (daily consumption of >2 standard drinks).⁷

Evidence is also emerging that long term oestrogen therapy (eg. through use of the oral contraceptive pill or hormone replacement therapy) may increase risk, as may exposure to high levels of radiation before 30 years of age.^{2, 7}

In pathological specimens, tumours may be invisible. Palpable tumours are normally more than 1cm in size and can be so large as to virtually replace the breast.³

• Ductal carcinoma: these tumours (also called scirrhous carcinoma) tend to have a hard consistency, average 1 to 2 cm diameter. May be attached to surrounding structures.
• Lobular: usually rubbery and poorly circumscribed.
• Medullary: well circumscribed; usually soft and fleshy; up to 5 cm in diameter.
• Mucinous: usually extremely soft, consistency of gelatin; pale-grey, well circumscribed.³

In some cases, invasive breast cancer is preceded by a 'pre-cancerous' condition such as ductal carcinoma in situ (DCIS) or lobular carcinoma in situ (LCIS).⁷ These in-situ carcinomas are abnormal proliferations of the epithelial cells of the mammary ducts or lobules. The cells share some abnormal cytological features with invasive breast cancer, but have not penetrated the basement membrane.⁶

Mucinous carcinomas are often slow-growing and are less likely to metastasise than other types.³

Early breast cancer has a good (greater than 80%) 5 year survival.⁷ Poor prognostic factors include increasing tumour size, higher histological grade, and the presence and number of lymph node metastases.⁷ In women with node-negative disease, the presence of oestrogen or progesterone receptors on cancer cells is also important.⁷

'Early' breast cancer refers to Stage I, Stage IIA, and early Stage IIB only.⁷

Carcinoma of the breast may be detected following investigation for a new breast symptom, such as a lump, pain, or nipple discharge; or may be detected on screening mammography.⁸

Simple tests including full blood count and serum biochemistry may suggest bone marrow or hepatic involvement.⁷ Further imaging, for example with CXR, bone scan, abdominal CT or liver ultrasound should be used only where clinically indicated.⁷

The diagnostic evaluation of a new breast symptom includes use of the 'triple test': history and examination, breast imaging with mammography or ultrasound, and tissue sampling via fine needle aspiration (FNA), core biopsy or open biopsy.⁷ Serological testing for cancer-specific antigens such as CA 15.3 is generally non-specific. It is not useful as an indicator of active disease.⁷

1. Australian Institute of Health and Welfare & National Breast Cancer Centre 2006. Breast cancer in Australia: an overview, 2006. Cancer series no. 34. cat. no. CAN 29. Canberra: AIHW.
2. Braunwald, Fauci, Kasper, Hauser, Longo, Jameson. Harrison's Principles of Internal Medicine. 16th Edition. McGraw-Hill. 2001
3. Cotran RS, Kumar V, Collins T. Robbins Pathological Basis of Disease Sixth Ed. WB Saunders Company 1999.
4. Dr Guy Van Hazel, Oncologist, Mount Hospital, Perth
5. Kumar P, Clark M. Clinical Medicine. Fourth Ed. WB Saunders, 1998.
6. National Breast Cancer Centre. 2003. 'The clinical management of ductal carcinoma in situ, lobular carcinoma in situ and atypical hyperplasia of the breast,' First Edition. National Breast Cancer Centre, Camperdown, NSW. [online] Available from: http://www.nbcc.org.au/bestpractice/resources/CMW_dcisbook.pdf
7. National Breast Cancer Centre. 2001. 'Clinical practice guidelines for the management of early breast cancer:Second edition'. National Breast Cancer Centre, Camperdown,NSW. [online] Available from: http://www.nhmrc.gov.au/publications/synopses/cp74syn.htm
8. National Breast Cancer Centre. 2003. 'A guide for women with early breast cancer.' National Breast Cancer Centre, Camperdown, NSW. [online] Available from: http://www.nbcc.org.au/resources/documents/EBC_earlyguide.pdf