The significance of breast screening
Breast cancer is a common malignant tumor that endangers women’s physical and mental health. Among women in Europe and the United States, one in every eight to nine women will develop breast cancer in their lifetime. Globally, 1.2 million women suffer from breast cancer and 500,000 women die from breast cancer every year, and its incidence is still increasing, posing an increasing threat to women’s life and quality of life. Breast cancer is in fact a malignant tumor that develops relatively slowly, and it is generally believed that its multiplication time is ≥2.5 years; from the formation of a single cell to the development of a clinically palpable 0.1 cm size lump, it takes 30 divisions to multiply, and it takes 5-8 years to grow to a 1 cm size lump in diameter. Therefore, there is enough time and space for early detection of breast cancer.
Since the 1970s, a large number of randomized controlled studies have increasingly demonstrated that breast cancer is another malignancy after cervical cancer that can reduce mortality through screening, and that such tumors often have a long clinical stage, early treatment can change the prognosis, and their screening methods are simple, reliable, sensitive, safe, and more economical.
Through the practice of breast cancer screening in countries with a high prevalence of breast cancer, most studies at the end of the 20th century concluded that in areas with a high prevalence of breast cancer, screening can reduce the mortality of breast cancer patients, but not the incidence of breast cancer. The possible benefits of screening are improved prognosis for patients with detected tumors and increased rates of breast-conserving treatment.
Population for screening
The peak age of incidence for women in China is 40-49 years, which is 10 years earlier than that of American women. The average age of breast cancer incidence in Shanghai is 47.9 years old, and the incidence range is 20 to 86 years old. It can be seen that the age of breast cancer screening for women in China should be earlier than that in the United States, and it is appropriate to start at the age of 30.
Generally, screening should be conducted once every 1 to 2 years. When to end the screening depends on the survival expectation of the person and the condition of other diseases. In principle, as long as one is in good health, one is a candidate for breast cancer screening.
In fact, only about 30% of breast cancer patients have clear risk factors. Therefore, although high-risk groups are the focus of breast cancer screening and may be the target of preventive interventions, the current screening and education efforts should target all women.
Census methods and steps
(1) Cohort establishment
First, the screening population should be defined. After identifying the census population, the total population of the target population is generally obtained from the household registration department of the local public security authorities and a database is established to obtain detailed information on the demographic structure of the target population and to establish a detailed population file of the target population to be screened and surveyed.
(2) Establishing census files
After the target population is identified, the first step of the census is to have a detailed questionnaire survey done by medical professionals, including each person’s menstrual history (age of menarche, age of menopause), birth history, breastfeeding, personal history and family history, etc.
(3) Medical examination by a specialist
In the second step of the screening, a detailed medical examination is conducted by a specialist. The clinical examination of the breast includes visual examination, palpation and regional lymph node examination.
Visual examination
Breast examination should be performed in bright light, with the patient sitting upright and removing her blouse to fully expose both breasts for bilateral comparison. First, check whether the shape, size and position of both breasts are symmetrical; second, check whether the skin is red, edematous, varicose veins and ulcers; third, check whether both nipples are at the same height and whether there is retraction and epidermal erosion and desquamation.
Palpation
Patients are usually examined in a sitting or standing position, combined with a supine position if necessary. The breast tissue should be gently pressed against the chest wall with the fingertips and palpated from top to bottom on the surface of the chest wall, avoiding grasping and pinching to avoid the illusion of the gland being picked up. For hypertrophic and sagging breasts, one hand can hold up the breast while the other palpates it. Palpate the breast in the order of upper inner, upper outer, lower outer, lower inner, nipple, and areola, and do not miss them. The nipples can be gently pulled bilaterally and compared on both sides, noting the mobility of the nipples; gently squeeze from around the breast toward the areola to observe whether there is nipple overflow.
Palpation of regional lymph nodes
The lymph nodes in the axilla and supraclavicular fossa are examined. The patient is in a sitting or standing position, and when examining the right side, the doctor holds the patient’s arm with the right hand so that the pectoralis major muscle is in a relaxed state, and then palpates with the left hand, and the opposite when palpating the left side. The palpation starts from the lateral side of the chest wall and gradually proceeds to the top of the axilla. Then use the thumb to palpate along the supraclavicular and sternocleidomastoid muscles to the left, right and up and down.
(4) Ancillary examinations
There are many examination techniques used for breast disease screening, but the only valuable and practical techniques are mammography and ultrasonography.
Ultrasonography is economical, simple, painless, without radiological damage, and can be used repeatedly for a short period of time, and is more suitable for young women, especially those who are pregnant or lactating. It can detect cysts as large as 2 mm in diameter; it can assist in X-ray examination to detect dense breast; it is accurate in positioning and shows clear levels of the breast; and it can detect axillary and supraclavicular lymph nodes.
The 2003 American Cancer Society (ACS) guidelines for breast cancer screening recommend that women begin breast screening at age 40; the benefits and risks of breast screening should be determined based on the health status and life expectancy of older women to determine whether they should continue screening. Healthy women should continue to have mammograms. The American College of Radiology recommends that every healthy woman should have informational x-rays of the breast for future screening and diagnosis, but no later than age 40. If a woman has a history of breast cancer or a family history of breast cancer, the age of screening should be earlier. Later on, depending on the physical examination, X-ray examination and the patient’s high-risk factors, etc., the decision of whether the interval between films should be 1 year or 2 years will be made. Unless clinically necessary for diagnosis, the interval between 2 films should not be too close, but generally not less than 1 year.
(5) Qualitative diagnostic examination
In the census, a puncture cytology or histological examination is required for suspicious subjects found to make a final qualitative diagnosis.
The so-called cytological diagnosis is to use a 5-10 ml common syringe connected with a 6-8 gauge needle to puncture the clinically suspicious lesion, then extract the cells in the mass with negative pressure, smear the cells on a slide, and ask the cytopathologist to make a diagnosis. This method is easy to perform, less invasive, less expensive, and timely in reporting, and correct fine needle aspiration will not cause tumor dissemination. However, because the number of cells obtained by fine needle aspiration is small, it requires a high level of diagnostic skills and there are very few cases of false positive results.
Histological diagnosis is to take biopsies from breast lesions for pathomorphological examination, to determine the benignity or malignancy of the lesions, to predict the patient’s prognosis and to guide the treatment. This is the gold standard for diagnosis. For suspicious lesions, especially for non-palpable nodules or microcalcifications, ultrasound or mammography-guided localized puncture biopsy is recommended for a definitive diagnosis.
Self-examination of the breast
Although breast screening can increase the detection rate of early breast cancer, due to social and economic constraints, it is impossible to include all women in the scope of regular screening, and even if regular screening is possible, lesions may be detected in the interval between screening. Breast self-examination is an easy, non-invasive method of breast health care with obvious advantages. In addition to economic reasons, it can be performed by the woman herself at the best time of her monthly menstrual cycle and allows for dynamic observation and follow-up for self-comparison. Regular breast self-examinations can increase the detection rate of early breast cancer. In fact, about 90% of the patients who naturally present with breast disease are seen by themselves for finding breast lumps.
Breast self-examination: Stand or sit in front of a mirror and carefully observe both breasts, including the size, shape, contour, skin and color of the breasts, any changes, and whether the nipples are elevated, retracted or overflowing. During palpation, the fingers should be stretched out and joined together, and the breast should be touched with the fingertips, with the left hand on the right side and the right hand on the left side, either in a clockwise or counterclockwise direction, without missing the nipple, areola and armpit. For women with larger breasts, they can be examined in a lying position with a little pressure on the fingers to touch the ribs. Breast self-examination should be done once a month, and the best time to do it should be within 7-10 days after menstruation, when the breast is relatively soft and painless and abnormalities are easily detected. Women who have stopped menstruating can choose a fixed time of the month for the examination. Each self-examination should be compared with previous self-examinations, and abnormalities should be detected and promptly referred to a doctor, so as to achieve the purpose of early detection and early diagnosis.
However, breast self-examination should not replace screening or regular checkups. Through a review of previous studies, the current evaluation of breast self-examination is.
(1) It is worth advocating and promoting as a breast self-care measure for the female population, and the average size of breast lumps found through regular breast self-examination is 0.8-2.1 cm.
(2) Education and guidance on breast self-examination for the female population failed to reduce the mortality rate of breast cancer in the population.
(3) In the guidance group, more benign breast lumps were detected, which increased the incision rate of benign breast lesions (suspected of “overtreatment”).
(4) For women with low levels of education, it may have some significance in shifting the timing of breast cancer diagnosis forward.
In summary, it is recommended that women should have monthly breast self-examinations from the age of 20 and clinical breast examinations every 3 years, one basic mammogram from the age of 35 to 40, and one mammogram per year from the age of 40. A clinical physical examination should also be performed at the time of the film.