1.Tumor Screening
(1) Tumor screening, or screening, is a kind of population cancer prevention measure for asymptomatic people, while medical examination for symptomatic people is called diagnosis.
(2) Breast cancer screening is to screen asymptomatic women through effective, simple and economical breast screening measures, with a view to early detection, early diagnosis and early treatment. Its ultimate goal is to reduce the mortality rate of breast cancer in the population.
(3) Screening is divided into 2 types: opportunistic screening ( o p p o r t u n i s t i cscreening) and group screening (mass screening). Opportunistic screening is an individual woman’s initiative or voluntary visit to a medical institution that provides breast screening; group screening is an organized community or unit entity that provides breast screening for women of appropriate age.
2. The starting age for women to participate in breast cancer screening
(1) Opportunistic screening is generally recommended to start at the age of 40, but for some people with high risk of breast cancer, the starting age of screening can be advanced to 20.
(2) There is no recommended age for group screening, and any group screening conducted in China is at the research stage, and there is a lack of data on cost-benefit analysis of different ages. The age of free breast cancer screening for rural women conducted by the Ministry of Health is 35-65 years old, and ultrasound examination is used mainly to supplement mammography.
3. Measures used for breast cancer screening
3.1 Mammography
(1) The role of mammography in reducing breast cancer mortality in women over 40 years of age has been recognized by most scholars abroad.
(2) It is recommended that 2 body positions should be routinely taken for each side of the breast, namely the cephalopodial (CC) and lateral oblique (MLO) positions.
(3) Mammogram images should be independently reviewed by 2 or more specialized radiologists.
(4) Mammography screening is highly accurate in Asian women over 40 years of age. However, mammography has poor penetration to young dense breast tissue, therefore, mammography is generally not recommended for women under 40 years of age without clear risk factors for breast cancer or abnormalities found on clinical physical examination.
(5) Routine mammography is not harmful to women’s health because of its low radiation dose, but normal women do not need to undergo repeated mammograms in a short period of time.
3.2 Breast clinical examination
(1) Clinical breast examination is not effective as a screening method for breast cancer alone, and there is no evidence that this method improves the early diagnosis of breast cancer and reduces mortality.
(2) Physical examination is generally recommended as a combined screening measure for breast screening and may compensate for missed mammography screening.
3.3 Breast self-examination
(1) Breast self-examination does not improve the detection rate of early diagnosis of breast cancer and reduce mortality.
(2) Since it can raise women’s awareness of cancer prevention, primary health care workers are still encouraged to teach women the method of breast self-examination once a month, and premenopausal women should be recommended to choose 7-10 days after menstruation.
3.4 Breast ultrasound examination
It can be used as a combined screening measure with mammography screening or as a complementary screening measure for those with BI-RADS grade 0 mammography screening results. Given that the Chinese population has a higher peak incidence of breast cancer, a high proportion of premenopausal patients and relatively dense breast, ultrasound can be used as an adjunct to breast screening.
3.5 Magnetic resonance imaging (MRI) of the breast
(1) MRI examination can be used as a supplemental examination measure for suspected cases detected by mammography, clinical breast examination or breast ultrasound examination.
(2) It requires high equipment requirements, is expensive, is time-consuming to examine, and requires intravenous injection of enhancer.
(3) It can be used in combination with mammography for breast cancer screening in certain breast cancer high-risk groups.
3.6 Other examinations
Current evidence does not support near-infrared scan, nuclear scan, ductal lavage and other tests as breast cancer screening methods.
4. Breast cancer screening guidelines for women in the general population
4.1 20 to 39 years of age
Breast screening is not recommended for non-high risk groups.
4.2 40 to 49 years of age
(1) Opportunistic screening is appropriate.
(2) 1 mammogram per year.
(3) Recommended in conjunction with clinical physical examination.
(4) Combination with ultrasound is recommended for dense breasts.
4.3 50-69 years of age
(1) Suitable for opportunistic screening and population screening.
(2) Mammography once every 1 to 2 years.
(3) Combination with clinical physical examination is recommended.
(4) Combination with ultrasound is recommended for dense breasts.
4.4 70 years of age or older
(1) Suitable for opportunistic screening.
(2) Mammography once every 2 years.
(3) Combination with clinical physical examination is recommended.
(4) Combined with ultrasound examination is recommended for dense breast.
5.Screening for high-risk groups of breast cancer
It is recommended that screening should be done in advance (before the age of 40) for people with high risk of breast cancer, and the screening interval is recommended to be once every six months.
6. Definition of high-risk group for breast cancer
(1) Those who have obvious genetic predisposition to breast cancer.
(2) Patients with previous moderate to severe atypical hyperplasia or lobular carcinoma in situ in the ducts or lobules of the breast.
(3) Patients with previous history of chest radiotherapy.