There are many factors related to the etiology of breast cancer, the common risk factors are
(1) Age at menarche and age at menopause: the risk of developing breast cancer is 2.2 times higher for those who have menarche earlier than 13 years old than those who are older than 17 years old; age at menopause: the risk increases for those who have menopause older than 55 years old than those who are younger than 45 years old; the risk of estrogen supplementation increases after menopause; long-term use of estrogen during menopause may increase the risk of breast cancer.
(2) Genetic factors of family history: Women with first degree of direct family history of breast cancer have 2 to 3 times higher risk of breast cancer than the normal population.
(3) Benign diseases of the breast.
(4) Dietary factors and obesity.
(5) Endocrine factors and hormones.
(6) Ionizing radiation.
(7) Bad living habits. Food: especially fatty diet can increase the risk of breast cancer. Alcohol consumption, weight gain may be an important risk factor for breast cancer in postmenopausal women
(8) Viral infection, etc.
Clinical manifestations
(i) Symptoms
In the early stage, there is no obvious clinical symptom or only mild breast pain, mostly dull or hidden pain, a few of them are pinprick-like pain, often intermittent and confined to the lesion, and the pain does not change with menstrual cycle. The pain does not change with menstrual cycle. In advanced stage, the pain is more intense when the cancer invades the nerve.
(ii) Physical signs
(1) Breast lump
Breast lump is often the main symptom for patients to seek medical consultation, and painless lump in breast is often the main symptom for patients to seek medical consultation. 80% of the lumps are found by patients themselves accidentally, and only a small percentage is found by doctors during physical examination.
①Location
The majority of lumps are located in the outer upper quadrant of the breast, followed by the inner upper quadrant, upper and central regions, and less frequently in other areas.
②Number
A single lump in one breast is usually common, and occasionally 2-3 lumps are seen.
③Size
The size of the masses varies. In the past, the masses were usually larger due to late presentation.
④Mass shape, surface and boundary
The shape of the lump is various, usually irregular, but also round and oval. In obese patients or those with masses located deeper in the posterior part of the breast, the masses are often flat and lamellar or have a limited glandular thickening, with an unsmooth or granular surface and unclear borders.
⑤ Texture of lumps
Most of them are solid, hard, or even stone-like hard. However, medullary carcinoma and lobular carcinoma, which are rich in cells, are often soft, mucinous carcinoma is tough, and cystic papillary carcinoma is cystic with fluctuating sensation.
(vi) Mobility
Compared with benign masses, their mobility is poor. If it invades the fascia of pectoralis major muscle, the mobility is even smaller when the pectoralis major muscle is contracted by forking the waist with force, and the mobility disappears if the pectoral muscle is involved. However, when the mass is small, the mobility is larger.
(2) Nipple overflow
The incidence of nipple overflow in breast cancer is low, usually below 10%. The overflow can be colorless, milky white, yellowish, brown, bloody, etc.; it can be watery, bloody, plasma or purulent, and the amount of overflow can be more or less. About 12%-25% of the bloody overflow is breast cancer, but in patients over 50 years old, the bloody nipple overflow can be up to 64% of breast cancer. If the breast cancer originates from large ducts or intra-ductal carcinoma, the combination of nipple discharge is more frequent. Sometimes there is only overflow but no obvious lump can be palpated, which can be the early clinical manifestation of intraductal carcinoma.
(3) Nipple and areola changes
If the cancer foci invade the nipple or subareolar area, the fibrous tissue and duct system of the breast may contract due to tumor invasion, pulling the nipple and making the nipple deviate to the side of the tumor. Further development of the lesion may cause the nipple to flatten, retract and sink until the nipple is completely retracted under the areola.
(4) Local skin changes
Depending on the early stage of breast cancer, different skin changes may occur. Some shallow early cancers can invade the suspensory ligament of the breast and make it contracted, or the tumor can adhere to the skin and make the skin sunken, resembling a dimple, which is clinically called “dimple sign”. The tumor can block the subcutaneous lymphatic vessels, which can lead to skin edema and “orange peel-like changes”. If the tumor invades the lymphatic vessels in the skin, small cancer foci can be formed around the tumor, which is called satellite nodules, and if most of the small nodules are distributed in pieces, it will be shaped as “armor-like changes”. In advanced cancer patients, the skin may be completely fixed or even broken, showing “cauliflower-like” changes, which will not heal after a long time. In inflammatory breast cancer, the local skin is inflammatory, ranging from light red to dark red, which is limited at the beginning but soon expands to most of the breast skin, accompanied by skin edema, thickened and rough skin to touch, and increased skin temperature, which is similar to mastitis during pregnancy and lactation, so clinical attention should be paid to differentiation.
(5) Change of breast contour
Due to the infiltration of tumor, the curvature of breast may be changed and slight convexity or concavity may appear. The breast may also be elevated, so that both nipples are not at the same level.
(6) Lymph nodes in the axilla and supraclavicular area
In early metastatic breast cancer, the lymph nodes in the axilla and supraclavicular fossa are usually not palpable. If the breast lump has malignant signs and the lymph nodes in the axillary and supraclavicular fossa are larger, harder, less mobile, or fused with each other, then it indicates a high possibility of metastasis. It is worth noting that occult breast cancer often has enlarged axillary or supraclavicular lymph nodes as the first symptom, while the primary lesion in the breast is very small and difficult to find clinically.