What Factors Cause Breast Cancer?
1. Precursor Lesions of Breast Cancer: It is impossible for normal cells to suddenly transform into cancer cells; rather, there is a gradual process from quantitative to qualitative change. Research shows that carcinogenesis is a proliferative process. If cell numbers increase without morphological changes, it is called simple hyperplasia. If both cell number and morphology show abnormal changes, it is termed atypical hyperplasia. Atypical hyperplasia at the intermediate stage carries a risk of malignancy. When atypical hyperplasia progresses to the late stage, cellular morphology and structure exhibit marked abnormalities approaching cancer, which constitutes a precancerous lesion. Precancerous lesions may follow three possible paths: progression toward cancer, improvement through effective treatment, or remaining static—even until death—without progressing to cancer. Since the transition from precancerous lesion to cancer takes a long time, this provides us with an opportunity to eliminate cancer risks.
2. Several factors contribute to breast cancer: (1) The exact cause of breast cancer remains unclear, but it is known to be associated with endocrine factors, genetics, viruses, immunity, and environment. Certain factors are closely linked to breast cancer development and are referred to as susceptibility factors, including: a family history of breast cancer, especially if the mother or sister has had breast cancer; earlier onset of breast cancer before menopause; bilateral breast cancer; increased risk if one breast is affected, making the other more susceptible; higher incidence in cases diagnosed with lobular intraepithelial neoplasia or multifocal cancer; increased risk in those with cystic breast hyperplasia, particularly if pathological examination confirms active papilloma in the ducts; increased risk in women with early menarche (<12 years), late menopause (>55 years), or menstruation lasting over 35 years; older age at first marriage, childlessness, or first full-term pregnancy after age 35; married but childless, or having given birth but not breastfeeding; history of pleurisy or pneumothorax, or multiple X-ray chest examinations; history of dysfunctional uterine bleeding or endometrial adenocarcinoma; obesity, especially significant obesity post-menopause or accompanied by hypothyroidism; weakened immune function; and all the above factors require heightened vigilance regarding breast cancer.
(2) Reports indicate that women who frequently undergo induced abortion have a higher chance of developing breast cancer. Sudden termination of pregnancy following induced abortion imposes a shock on ovarian function, causing a sharp decline in hormones and abrupt cessation of breast growth, leading to glandular atrophy. This dramatic fluctuation represents a physiological anomaly. Besides disrupting ovarian function, it may also lead to breast stagnation, resulting in masses and various breast diseases, thereby increasing the risk of breast cancer. Thus, repeated induced abortions are harmful to health and are related to breast cancer incidence. Active contraception should be practiced to avoid repeated induced abortions.
(3) Whether breast cancer is hereditary is a sensitive issue for families affected by the disease. Numerous facts confirm a familial tendency in breast cancer occurrence. Clinically, daughters of mothers with breast cancer are 2–3 times more likely to develop the disease than average women, and they tend to develop it about 10 years earlier. The risk is even greater among sisters—if a mother has breast cancer and one of her sisters also has it, her daughter's risk of developing breast cancer before age 40 is 40–50 times higher than women without a family history of breast disease. If the previous generation had bilateral breast cancer, the risk for descendants is three times higher than in families with unilateral breast cancer, and six to nine times higher than in the general population.
In reality, breast cancer itself is not inherited. The higher incidence in families is due to indirect effects of human genetic factors on breast cancer development. Therefore, what is passed down is not the tumor itself, but the susceptibility to developing tumors. Under this predisposition, influenced by environmental, dietary, psychological, and endocrine factors, individuals are more prone to tumor formation than others. In summary, breast cancer is not directly inherited, but an indirect susceptibility exists and continues to be studied.
3. Prevention of Breast Cancer:
Promote self-breast examination among women for early detection of abnormalities. Regular breast cancer screening programs facilitate early detection, diagnosis, and treatment, significantly improving survival rates and reducing recurrence—this holds great practical significance.
Cystic breast hyperplasia is a benign proliferative condition, but a small portion may progress from typical hyperplasia to atypical hyperplasia, where cells increase in number and exhibit abnormal morphology, eventually developing into breast cancer. Thus, timely treatment and regular check-ups are essential to prevent missed diagnoses of breast cancer.
Although most breast lumps are benign, malignant micro-lumps may be mixed in among them. Therefore, modern auxiliary diagnostic methods must be fully utilized to detect breast cancer early. Breast cancer is a serious threat to women's health. Promoting self-examination and conducting breast screenings, combined with widespread public health education and cancer prevention awareness campaigns across society, is of vital importance in improving early detection rates of breast cancer.
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