1.Definition, purpose and classification of breast cancer screening
(1) Tumor screening, or screening, is a cancer prevention measure for asymptomatic people, while medical examination for symptomatic people is called diagnosis.
(2) Breast cancer screening is to screen asymptomatic women for early detection, early diagnosis and early treatment through effective, easy and economical breast screening measures. Its ultimate goal is to reduce the mortality rate of breast cancer in the population.
(3) Screening is divided into two types: opportunistic screening and mass screening. Opportunistic screening is when women go to medical institutions that provide breast screening on their own initiative or voluntarily; mass screening is when community or unit entities provide breast screening for women of appropriate age in an organized manner.
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 high-risk groups 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 currently conducted in China is at the research stage, and there is a lack of data on cost-benefit analysis at different ages.
3. Measures used for breast cancer screening
(1) Mammography
a. The role of mammography in reducing breast cancer mortality in women over 40 years of age has been recognized by most foreign scholars.
b. It is recommended that two positions should be taken routinely for each breast, namely the cephalic foot axis (CC) position and the lateral oblique (MLO) position.
c. Mammograms should be independently reviewed by two or more specialized radiologists.
d. Mammography screening is highly accurate in Asian women over 40 years of age. However, mammography does not penetrate well into young dense breast tissue, so mammography is not recommended for women under 40 years of age without clear risk factors for breast cancer or abnormalities found on clinical examination.
e. The radiation dose of routine mammography is low and not harmful to women’s health, but normal women do not need to have repeated mammograms in a short period of time.
(2) Clinical breast examination
a. Clinical breast examination alone is not effective as a screening method for breast cancer, and there is no evidence that this method can improve the early diagnosis of breast cancer and reduce the mortality rate.
b. Physical examination is generally recommended as a combined screening measure for breast screening, which may compensate for the omission of mammography screening.
(3) Self-examination of the breast
a. Breast self-examination cannot improve the detection rate of early diagnosis of breast cancer and reduce the mortality rate.
b. Since it can raise women’s awareness of cancer prevention, primary health care workers are encouraged to teach women the method of breast self-examination once a month, and premenopausal women should be advised to perform it 7-10 days after menarche.
(4) Ultrasound examination of breast
This can be done as a combined screening mammogram or as a complementary screening mammogram for those with a BI-RADS level 0 screening result. Given that the Chinese population has a higher incidence of breast cancer, a higher proportion of premenopausal patients, and a relatively dense breast, ultrasound can be used as an adjunct to breast screening.
(5) Magnetic resonance imaging (MRI) of the breast
a. MRI examination can be used as a supplement to mammography, clinical examination of the breast or suspected cases detected by ultrasound examination of the breast.
b. It requires high equipment requirements, is expensive and time-consuming, and requires intravenous enhancement.
c. It can be used in combination with mammography for breast cancer screening in certain groups with high risk of breast cancer.
(6) Other tests
The current evidence does not support the use of near-infrared scan, nuclear scan and ductal lavage as breast cancer screening methods.
4. Breast cancer screening guidelines for women in general population
(1) 20-39 years of age
Breast screening is not recommended for non-high risk groups.
(2) 40-49 years old
a. Opportunistic screening is appropriate.
b. One mammogram per year.
c. Recommended in conjunction with clinical examination.
d. Combination with ultrasound is recommended for dense breasts.
(3) 50-69 years of age
a. Suitable for opportunistic screening and population screening.
b. Mammogram every one to two years.
c. Combined with clinical examination is recommended.
d. Combination with ultrasound is recommended for dense breasts.
(4) 70 years of age or older
a. Suitable for opportunistic screening.
b. Mammography once every 2 years.
c. Combined with clinical examination is recommended.
d. Combination with ultrasound is recommended for dense breasts.
5. Screening for high-risk groups of breast cancer
In addition to clinical examination, B-ultrasound and mammography, new imaging methods such as MRI can be used.
6. Definition of high-risk group for breast cancer
(1) Those who have a clear genetic predisposition to breast cancer (see Appendix I for details).
(2) Patients with previous ductal or lobular moderate to severe atypical hyperplasia or lobular carcinoma in situ.
(3) Patients with previous history of chest radiotherapy.
Appendix I: Hereditary high-risk groups
Hereditary Breast Cancer – Ovarian Cancer Syndrome Genetic Testing Criteria a, b
1.Carriers of BRCA1/BRCA2 gene mutation in blood relatives.
2.Patients with breast cancer who meet 1 or more of the following conditions c.
(1) Age of onset ≤ 45 years.
(2) Breast cancer patients ≤50 years of age with 1 consanguineous relative d who is also ≤50 years of age and/or 1 or more consanguineous relatives of any age with ovarian epithelial/fallopian tube/primary peritoneal cancer.
(3) A single individual with 2 primary breast cancers e and age at first presentation ≤ 50 years.
(4) Two or more consanguineous close relatives of any age with breast and/or ovarian epithelial, fallopian tube, or primary peritoneal cancer of any age of onset, regardless of age of onset.
(5) A male consanguineous relative with breast cancer.
(6) Combined past history of ovarian epithelial cancer, fallopian tube cancer, or primary peritoneal cancer.
(3) Patients with ovarian epithelial cancer, fallopian tube cancer and primary peritoneal cancer.
4.Patients with male breast cancer.
5.Family history of the following.
(1) Any of the above conditions among first or second degree relatives who are related by blood.
(2) Two or more third-degree relatives with consanguinity who have breast cancer (at least one with age of onset ≤ 50 years) and/or ovarian epithelial/fallopian tube/primary peritoneal cancer.
Notes.
1. Meeting 1 or more of the conditions suggests a possible hereditary breast cancer-ovarian cancer syndrome and warrants specialized evaluation. When reviewing the patient’s family history, paternal and maternal relatives with cancer should be considered separately. Early-onset breast cancer and/or ovarian epithelial, fallopian tube, and primary peritoneal cancers at any age suggest the possibility of hereditary breast-ovarian cancer syndrome, which in some families with hereditary breast-ovarian cancer syndrome also includes prostate cancer, pancreatic cancer, gastric cancer, and melanoma.
2. Other considerations: Individuals with limited family history, such as female first- or second-degree relatives 45 years of age, in which case the likelihood of carrying the mutation tends to be underestimated. Patients with triple negative breast cancer with an age of onset ≤40 years should be considered for testing for BRCA 1/2 gene mutations.
3.Breast cancer includes invasive and intraductal cancers.
4, Next of kin refers to first, second and third degree relatives.
5, 2 primary breast cancers include bilateral breast cancers or 2 or more primary breast cancers of definite different origin in the same side of the breast.