With rising living standards and the development of fast food diets, the incidence of obesity in the global population has been increasing, and women are no exception, with 29% of unpregnant women between the ages of 20 and 39 in the United States being overweight or obese. In our country, obesity is also becoming a growing health problem. Obesity brings a series of reproductive and medical problems, obese patients are susceptible to diabetes and cardiovascular disease is widely known, but obesity and tumors, especially female obesity and gynecological tumor relationship is not well understood and known.
I. Definition of obesity
World Health Organization (WHO) according to the body mass index (BMI, bodymass index) to define obesity, body mass index refers to the weight (kg) divided by the square of height (m). Internationally, BMI≥30 is judged as obese. The standard for judging obesity in China follows the Guidelines for the Prevention of Overweight and Obesity in Chinese Adults issued by the Ministry of Health.
BMI in 18.5 ~ 23.9kg/m2 between normal weight, BMI in 24 ~ 27.9kg/m2 between overweight, BMI ≥ 28 for obese.
Second, obesity and tumor susceptibility
1, obesity affects human immune function: research shows that obese patients lacking moderate exercise have lower natural killer cell (NK) activity compared with normal people; obese people often prefer fat and carbohydrate food, thus affecting the absorption of trace elements iron, zinc, selenium and other vitamins. The biological activity of trace elements is expressed through the relevant enzymes, and deficiencies of zinc and iron will affect the metabolic processes of lymphocytes and neutrophils, thus impairing cellular immune function. Female weight rise can lead to the increase of CD4, CD8, lymphocyte number and WBC number, and similar studies found that the number of white blood cells, lymphocytes and monocytes in obese patients increased, but inhibited the proliferation of mitosis-induced lymphocytes, and the disorder of immune function is easy to induce tumors.
2, obesity and oxygen-carrying capacity decline: obese patients due to the accumulation of fat in the neck, lying down when the airway is obstructed, prone to obstructive sleep apnea hypoventilation syndrome (OSAHS), OSAHS patients due to the lack of oxygen at night, free radical generation increased, blood pH decreased, red blood cell oxygen-carrying capacity decreased, so that tissue metabolism and the ability to remove abnormal substances decreased is also one of the causes of tumor.
3, obesity and inflammation: inflammation is a basic pathological process mainly based on defense reaction to the damage of inflammatory factors, and research shows that the occurrence of many kinds of tumors is related to chronic inflammatory stimulation. A variety of adipocytic factors secreted by adipocytes, such as TNF-α, IL, adiponectin and leptin, can cause, mediate or participate in the inflammatory response. Obesity, especially visceral obesity, adipocyte hyperplasia, hypertrophy, can secrete a large number of pro-inflammatory or inflammatory factors, therefore, some scientists proposed that “obesity is a low degree of inflammatory state”. Chronic inflammation can induce rapid cell differentiation, increase cell replication process error, invalid DNA replication and stimulate mutation, thus inducing tumor.
4. Hormonal environment changes in obese women.
(1) the ovaries and adrenal glands secrete more androgens, high androgens cause a series of endocrine and metabolic disorders, prone to insulin resistance and diabetes.
(2) Increased peripheral fat in obese women and increased estrogen conversion by aromatase in adipose tissue, leading to increased incidence of estrogen-related tumors.
(3) Decreased sex hormone-binding proteins in the blood of obese women, leading to increased levels of free, bioavailable estrogen in the circulation.
(4) obesity affect ovulation, the lack of progesterone cycle regulation, leading to menstrual disorders estrogen-related diseases occur.
5, obesity and mood disorders: research shows that obesity and depression and other bad mood closely related, and its relevance is directly proportional to the degree of obesity. Obesity causes depression and social, psychological, cultural and other factors, usually due to the negative social evaluation of overweight people led to the lack of self-acceptance and self-identity of obese people, eventually leading to depression, there are also studies that dieting, exercise and other forced weight loss pressure leads to depression. Long-term depression seriously affects the body’s immune and metabolic functions, and is likely to induce tumors.
Obesity and the occurrence of gynecological tumors
1.Obesity and endometrial cancer.
The occurrence of endometrial cancer is closely related to obesity, and the incidence of endometrial cancer increases with the increase of BMI. Women with BMI>29 have 3 times greater risk of endometrial cancer than those with BMI<23, and the risk of endometrial cancer increases with every 5kg increase in body weight (OR=1.2). In addition to BMI, body fat distribution is also an independent prognostic factor for the development of endometrial cancer. In central obese individuals, fat is deposited in the heart and internal organs, and the thickest part of the body is in the abdomen, with an increased waist-to-hip ratio. Central obesity is associated with decreased concentrations of sex hormone-binding proteins and increased levels of free estrogen, and is often associated with insulin resistance and systemic inflammatory responses, thus increasing the risk of endothelial cancer compared to peripheral obesity.
In young women, obesity is often associated with a variety of metabolic abnormalities such as high insulin and high androgens, which can manifest clinically as disturbances in the menstrual cycle (anovulatory menstruation) or amenorrhea, reduced fertility or infertility, such as polycystic ovary syndrome (PCOS), which lacks progesterone production due to the inability to form dominant follicles and the absence of ovulation and corpus luteum formation. PCOS patients have many small follicles in the ovaries that continue to secrete estrogen, leaving the endometrium under prolonged estrogen stimulation without progesterone counteracting it.
In recent years, the diagnosis and treatment of PCOS have been gradually standardized, but most patients and doctors still focus on fertility issues. In fact, anovulation not only affects fertility, but the endometrium under the effect of high estrogen without progesterone counteracting for a long time will develop hyperplasia, starting with simple hyperplasia, then compound hyperplasia and atypical hyperplasia, which will eventually progress to cancer if it develops for a long time. PCOS as a high risk factor for endometrial hyperplasia and endometrial cancer has been confirmed by more and more studies. Therefore, patients with PCOS should undergo long-term treatment according to different age and fertility requirements: from adolescence to pre-fertility, symptomatic treatments such as regular progestogen withdrawal for bleeding and oral short-acting oral contraceptives can be used to regulate the menstrual cycle, avoid functional uterine bleeding and control long-term complications; during reproductive age, ovulation promotion and pregnancy are aimed at; after completion of reproductive function, adjustment of After the completion of reproductive function, the aim is to adjust menstruation, protect endometrium, prevent endometrial cancer and metabolic abnormalities and other long-term complications.
The incidence of endometrial hyperplasia and endometrial cancer in postmenopausal obese women is 3.0% and 12.1% respectively, both much higher than that in non-obese women. There are two reasons for the increased chance of endometrial cancer in elderly obese women: on the one hand, the aromatase of peripheral fat can synthesize more estrogen, on the other hand, high insulin and androgens reduce the production of sex hormone binding protein, resulting in the increase of free bioavailable estrogen in the body, and the long-term high estrogen stimulation in the body causes endometrial carcinogenesis.
2. Obesity and breast cancer.
The same is due to the increase of synthetic estrogen in adipose tissue and the decrease of hormone synthesis protein resulting in the increase of free estrogen in plasma, the risk of breast cancer in obese women after menopause increases significantly, obese women are often accompanied by hyperinsulinemia, by increasing the level of insulin-like growth factor and leptin, promoting the synthesis of estrogen in breast epithelial cells, triggering the growth of cancer. In addition, obese women are less likely to find abnormal lumps in the breast than women of normal weight, often making breast lumps found late.
3.Obesity and other gynecological tumors
Obesity itself is not directly related to cervical cancer and ovarian cancer. However, due to the influence of psychological factors such as fear of embarrassment or discomfort, obese women are less likely to insist on routine check-ups, thus easily missing the opportunity to detect early cervical lesions and microscopic ovarian lesions. Even if they are examined, the difficulties of being overweight and changing body position make it difficult for obese patients to get a fully satisfactory examination, and the incidence of missed examinations and unsatisfactory examinations increases significantly when compared with women of normal weight. On the other hand, because of the thick abdominal wall and the accumulation of fat in various parts of the body, obese women can easily hide the early symptoms of tumors such as abdominal distension, ascites and abdominal pain, which increases the chance of finding ovarian cancer and cervical cancer among obese women, especially the late stage ovarian cancer and cervical cancer.
Obesity and tumor outcome
Obesity is often related to the poor prognosis of malignant tumors, for the following reasons.
(1) obese women are more likely to miss physical examination, or inaccurate physical examination and make the early tumor was found to reduce the opportunity, and therefore the tumor in the late stage of the opportunity to be diagnosed than those with normal weight;.
(2) The chance of combined hypertension, diabetes mellitus and thromboembolic diseases in obese patients is much higher than that in normal weight patients, thus the chance of perioperative cardiovascular and cerebrovascular accidents, poor wound healing, serious infections and other postoperative complications in obese patients with malignant tumors significantly increases, which affects survival and prognosis.
(3) Obese patients are in a state of chronic inflammation and low immunity for a long time, which easily induces tumor growth and promotes tumor infiltration, resulting in rapid tumor development and higher chances of recurrence and metastasis.
(4) Obese patients lack exercise and lead unhealthy lifestyles, and the function of important organs such as heart, lung, liver and kidney is poorer than that of normal weight patients, thus making it difficult to ensure the smooth implementation of standardized treatment because of poor tolerance to radical surgery and postoperative radiotherapy.
In conclusion, obesity originates from unhealthy lifestyle and dietary habits, and the excessive estrogen caused by obesity in women is closely related to endometrial cancer, breast cancer and other malignant tumors, while the abnormal psychology, chronic inflammation, low immunity and various comorbidities associated with obesity are related to the easy occurrence, difficult detection, rapid development, poor treatment tolerance and poor prognosis of malignant tumors. Therefore, it is of great significance to enhance education, promote healthy lifestyle, avoid and treat obesity among women for the prevention, screening, early detection, early treatment and improvement of prognosis of female malignant tumors.