Breast cancer is an increasing public health problem. There have been substantial advances made in treatment of breast cancer. However, the incidence is rising in most countries and it is estimated that it will rise further over the next 20 years despite the current attempt to prevent the disease.
The increase in the incidence of breast cancer is not surprising as there has been an increase in the western world in the risk factors which predispose women to breast cancer. These include younger age of menarche (age of first period), older age of first pregnancy, fewer pregnancies, shorter or no periods of breastfeeding, and later menopause.
Other risk factors which are increasing the incidence of breast cancer include physical inactivity with a reduction in daily exercise, hormone replacement therapy, increased alcohol consumption, and obesity.
The impact of hereditary breast cancer has also increased. Data suggests that both familial and non-familial risks have increased.
For Victorian women, 3 out of every 10 cancers that occur will be in the breast and this significantly outnumbers the next 3 most common cancers, bowel, lung, and melanoma. Breast cancer is more common in women post menopause. 51% of all cancers occur in women aged 50 to 69 and 27% of women in aged over 70, although it can be seen in younger women.
Breast cancer in men is rare. It is responsible for about 1% of all breast cancers and makes up less than 1% of all male cancers. The highest incidence is in African countries (Uganda 5% and Zambia 15%). It is more common in BRCA mutation carriers. If there is any male breast cancer in the family, a genetic test would be indicated. Most of the literature is based on case controls in retrospective studies with a small number of patients. There have been no randomised controlled trials in the adjuvant treatment of male breast cancer. Most clinical trials have closed due to lack of patient numbers. The treatment strategies for male breast cancer are largely extrapolated from the treatment of female breast cancer. The incidence of male breast cancer in the developed world has climbed throughout the 2000’s and is now steady. Mortality for male breast cancer is down by 28% as compared to female breast cancer down by 52%. Standard treatment applies to male breast cancer and includes surgery, chemotherapy, radiotherapy, and endocrine treatment.
In Victoria, breast cancer is the most common new cancer with almost 4075 diagnoses in 2013 (almost 30% of all cancers). However, the mortality for Victorian women with breast cancer has significantly decreased to 2.5% per year over the past 20 years. This has been seen across all age groups. This is thought to be due to success of programs such BreastScreen Australia, increased breast health awareness, and surveillance of women, particularly those at high risk due to genetic factors.
It also reflects significant advances in the surgical, medical, and radiation oncology treatment of breast cancer.
3% of all women diagnosed with breast cancer will be diagnosed with early stage disease. 44% stage I and 34% stage II. Stage IV disease makes up a very small proportion, 6% of all tumours are unstaged, and the majority of these are in women who are greater than 80 years of age and are not having any further surgical treatment.
45% of invasive breast cancers and two-thirds of all ductal carcinoma in situ are diagnosed through BreastScreen (aged 50 to 69 years). These tumours tend to have a better prognosis in that they are smaller and have less nodal disease.
Breast cancer can present with a variety of symptoms. These may include a breast lump, breast thickening, nipple discharge (spontaneous single duct discharge), and changes to the skin overlying the breast or the nipple. It may also present with changes in the contour or shape of the breast, a lump under the armpit, breast pain (approximately 10% of all breast cancers present with breast pain) .There may be also other signs such as nipple retraction, nipple eczema , skin dimpling, or changes in the skin over the breast, swelling or deformity of the breasts. It is important that any patient that has any abnormalities to the breast is seen by a specialist breast surgeon. In many cases breast cancer may be totally asymptomatic and found on routine breast imaging.