Breast cancer is the first malignant tumor in women all over the world, and the incidence rate is increasing by 2% every year. 1.2 million women worldwide develop breast cancer and 500,000 women die from it every year. North America and Northern Europe are the regions with high incidence of breast cancer, one out of every 7-10 women will have breast cancer in their lifetime, and the incidence rate is about 4 times higher than that in Asia, Africa and Latin America.
In recent years, the number of new cases has been increasing at a rate of 3% to 4% per year, exceeding the global rate by 1 to 2 percentage points. In major cities such as Beijing and Shanghai, breast cancer has become the first malignant tumor in women.
Causal factors of breast cancer
1. Hormonal factors
Early menarche (age of menarche <13>17: 2.2 times)
Late childbearing
Decrease in the number of reproduction and the number of years between reproduction
Failure to breastfeed
Spontaneous or induced abortion
Late menopause (age at menopause >55 years /<45: 2 times)
Hormone replacement therapy
Use of contraceptive pills
2. Genetic factors
History of breast cancer in first-degree immediate family (2~3 times relative risk)
P53, BRCA 1-2 mutations
3.Benign breast disease
High epithelial hyperplasia or atypical hyperplasia
4.Lifestyle and dietary habits
The incidence of breast cancer among Japanese women who immigrated to the United States and the first generation born in the United States is no different from that of local women
Obesity: increased estrogen in adipose tissue
5.Ionizing radiation
After irradiation by Dochino
II. Measures for early diagnosis of breast cancer
The basic three are self-examination, clinical physical examination and mammogram.
1.Self-examination of breast
The advantages are economic, convenient and no damage to human body. Women who participate in breast self-examination should be provided with adequate and reasonable guidance and educated on the basic knowledge of breast cancer, including the effect of menstrual cycle on breast, clinical manifestations of breast cancer and the significance of early detection of breast cancer. The time is the 9th to 11th day after menstruation.
2. Clinical examination
”Lumps” are not the first sign essential to diagnose breast cancer. The early detection of breast cancer can be facilitated by localized glandular thickening, nipple overflow and nipple erosion. Mild nipple retraction, mild indentation of the breast skin and mild edema of the areola are valuable clinical signs.
3.Mammogram
It has the advantages of easy operation, rapid diagnosis, and easy image retention and review. Studies have confirmed that mammography screening can reduce the mortality rate of breast cancer by 20-40% in patients aged 50-69 years old and by about 20% in patients aged 40-49 years old. For women over 50 years of age, mammograms can detect breast cancer on average more than 3 years earlier than controls; and for women 40-49 years of age, they can also detect breast cancer on average 1.7 years earlier. Younger women have denser mammary glands and the diagnostic sensitivity of X-ray is not high, and considering the possible radiological damage of mammography, frequent examinations are not advisable. Therefore, for women under 35 years old, other examinations are recommended.
4.Other
4.1 Breast ultrasound
Because of its obvious advantages in identifying cystic and substantial breast masses, especially in patients with dense breast texture, it is usually used for further screening of abnormal lesions detected by mammography or physical examination screening.
4.2 Breast magnetic resonance imaging (MRI)
The sensitivity and specificity of MRI of the breast with the application of contrast are high. However, it is expensive and not suitable for large-scale population screening.
At present, it is mainly suitable for screening of women with family history of breast cancer or carrying genes related to breast cancer and evaluation of breast cancer before and after treatment.
4.3 Nipple discharge screening
For patients with clinically inapplicable nipple discharge, commonly used methods include nipple discharge cytology, mammography, and ductoscopy.
4.4 Cytologic/histologic examination
Fine needle aspiration cytology (FNA) is a safe, convenient, and minimally invasive pathological examination method, but it can only provide a cytologic diagnosis and cannot distinguish pathologically between breast carcinoma in situ and invasive carcinoma, nor can it make a definitive determination of certain cell morphological abnormalities. Hollow-core needle biopsy and vacuum-assisted minimally invasive breast biopsy, which emerged in the mid-1990s, have led to a significant improvement in diagnostic accuracy. The promotion of imaging-guided minimally invasive breast biopsy can significantly reduce the cost of breast cancer screening and allow women to participate actively in the early diagnosis of breast cancer by eliminating the fear of hospitalization or surgery.
Surgical excisional biopsy: accurate diagnosis and can be curative for benign breast disease.
Breast cancer screening guidelines developed by the American Cancer Society (ACS) in 1997
Age range
Screening interval
X-ray screening
Clinical physical examination
Self-examination
General women
18-39 years old
Not recommended
Once every 3 years
Once a month
≥ 40 years old
Once a year
Once a year
Once a month
High-risk women
< 35 years old< p="">
Not recommended
Once in 4~6 months
Once a month
≥35 years old
Once a year
Once in 4~6 months
Once a month
Notes.
n Premenopausal women should choose 9-11 days after the onset of menstruation (when breast tissue is least affected by hormones in the body); postmenopausal women should choose a day that is easy to remember, such as the first day of the month.
n High-risk women are those who have a significant tendency to have a family history of breast cancer, a first-degree relative with bilateral breast cancer before menopause, positive for breast cancer-related genes (e.g., BRCA1, BRCA2), and a previous history of breast cancer or atypical hyperplasia.