1.Definition, purpose and classification of breast cancer screening
(1) Tumor screening, or screening, is a cancer prevention measure for asymptomatic people, while the medical examination for symptomatic people is called diagnosis.
(2) Breast cancer screening is the screening of 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 2 types: opportunistic screening and mass screening. Opportunistic screening is an individual woman’s initiative or voluntary visit to a medical institution that provides breast screening; mass 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 high-risk groups of breast cancer, the starting age of screening can be advanced to 20.
(2) The recommended age for group screening is 50-69 years old.
3.Measures used for breast cancer screening
(1) Mammography
1) The role of mammography in reducing breast cancer mortality in women over 40 years old has been recognized by most scholars at home and abroad.
2)It is recommended that 2 body positions should be routinely taken for each side of the breast, i.e. cephalopodial (CC) position and lateral oblique (MLO) position.
3) Mammogram images should be independently reviewed by ≥2 professional radiologists.
4) The accuracy of mammography screening is high for Asian women over 40 years of age. However, mammography has poor penetration to young dense breast tissues, so it 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) The radiation dose of routine mammography is low and will not endanger women’s health.
(2) Clinical breast examination
1)It is not effective as a screening method for breast cancer alone, and there is no evidence that this method can improve the early diagnosis rate of breast cancer and reduce the mortality rate.
2) It is generally recommended as a combined screening measure with mammography screening and may compensate for missed mammography screening.
3) Self-examination of the breast
1)It cannot improve the early diagnosis rate of breast cancer and reduce the mortality rate.
2) Since it can improve 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 d after menstruation.
(4) Ultrasound examination of breast
1) Alone as a measure for breast cancer screening has yet to be proven. It may be valuable for screening of dense breast.
2) It can be used as a combined screening measure with mammography screening or as a supplemental screening measure for those with BI-RADS-0 mammography screening results.
(5) Breast MRI (magnetic resonance imaging)
1) It can be used as a supplemental examination measure for suspected cases detected by mammography, breast clinical examination or breast ultrasound examination.
2) High equipment requirements, expensive, time-consuming examination, and intravenous injection of enhancer is required.
3) It can be used in combination with mammography for breast cancer screening in certain breast cancer high-risk groups.
(6) Other tests
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
(1) 20 to 39 years of age
Breast screening is not recommended for non-high risk groups.
(2) 40 to 49 years of age
1) Suitable for opportunistic screening.
2)1 mammogram per year.
3)Recommended in conjunction with clinical physical examination.
4) Combination with ultrasound is recommended for dense breasts.
(3) 50-69 years old
1)Suitable for opportunistic screening and population screening.
2) Mammogram every 1 to 2 years.
3)Recommended in combination with clinical physical examination.
4)Combination with ultrasound is recommended for dense mammary glands.
(4) 70 years of age or older
1)Suitable for opportunistic screening.
2) Mammogram every 2 years.
3)Combination with clinical examination is recommended.
4)Combination with ultrasound is recommended for dense breast.
5) Screening advice for people with high risk of breast cancer
It is recommended that screening should be conducted earlier (before the age of 40) and the interval between screening should be once every six months.
6. Definition of high risk group for breast cancer
(1) Those who have a clear genetic predisposition to breast cancer (see Annex 1 for details).
(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 lymphoma who have previously undergone chest radiotherapy.
Hereditary high risk group
Hereditary breast cancer-ovarian cancer syndrome genetic testing criteriaa, b
1.Carriers of BRCA1/BRCA2 gene mutation in blood relatives.
2.Patients with breast cancer who meet 1 or more of the following conditionsc.
(1) Age of onset ≤ 45 years.
(2) Breast cancer patients with age of onset ≤ 50 years and 1 consanguineous relatived who is also a breast cancer patient with age of onset ≤ 50 years and/or 1 or more consanguineous relatives with ovarian epithelial/fallopian tube/primary peritoneal carcinoma of any age.
(3) A single individual with 2 primary breast cancere and age at first presentation ≤ 50 years.
(4) Any age of onset and 2 or more consanguineous close relatives with breast and/or ovarian epithelial/fallopian tube/primary peritoneal cancer of any age of onset at the same time.
(5) A consanguineous male next of kin with breast cancer.
(6) Combined past history of ovarian epithelial cancer/fallopian tube cancer/primary peritoneal cancer.
3. Patients with ovarian epithelial cancer/ fallopian tube cancer/ primary peritoneal cancer.
4.Patients with male breast cancer.
5.Family history of the following.
(1) Blood related first or second degree relatives who meet any of the above criteria.
(2) Two or more patients with breast cancer (at least one with age of onset ≤ 50 years) and/or ovarian epithelial cancer/fallopian tube cancer/primary peritoneal cancer among related third-degree relatives.
Notes.
a. Meeting 1 or more of the conditions suggests a possible hereditary breast cancer-ovarian cancer syndrome, necessitating 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/primary peritoneal cancer at any age suggest a possible 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.
b. Other considerations: individuals with a limited family history, such as <2 female first- or second-degree relatives, or female relatives >45 years of age, in which case the likelihood of carrying the mutation is often underestimated. Patients with triple negative breast cancer with an age of onset ≤ 40 years should be considered for testing for BRCA1/2 gene mutations.
c. Breast cancer includes invasive and intraductal cancers.
d. Close relatives are defined as first-, second- and third-degree relatives.
e. 2 primary breast cancers include bilateral breast cancers or 2 or more definite primary breast cancers of different origin in the same side of the breast.