Colorectal cancer, collectively known as colorectal cancer, is a common malignant tumor of the digestive system and a serious threat to human health. Due to the unique physiological and anatomical characteristics of women, female colorectal cancer has its own special characteristics in terms of incidence and diagnosis and treatment.
The incidence rate of female colorectal cancer in China is increasing and catching up with that of men
The high incidence of colorectal cancer is mainly located in developed countries such as Northwest Europe and North America, while the incidence rate in China is lower. Although the average incidence rate of colorectal cancer worldwide is lower for women than men, the incidence rate of women has been increasing faster in recent years. According to the WHO report, the global new cases of female colorectal cancer are in the 3rd place of female malignant tumors, and the highest incidence rate of female colorectal cancer is in New Zealand, which is 42.2/100,000. and 40.7/100,000 respectively). In China, colorectal cancer ranks 6th in the incidence of malignant tumors in women, and the incidence of colorectal cancer in women is also increasing, with the ratio of male to female increasing from 1.50:1 in the 1980s to 1.26:1 in the 1990s.
Aging and increasing proportion of right-sided colon cancer patients
Recent statistics show that colorectal cancer in China tends to age, and female patients also show this trend. The statistics from 1981 to 2000 in Tianjin show that the median age of colon cancer incidence in women is 65 years. The analysis of the age and location of colorectal cancer in Japan from 1974 to 1994 showed that the proportion of female patients older than 70 years old increased significantly, and the proportion of right-sided colon cancer among all female colon cancers also increased significantly. The incidence of colon cancer in developed countries is equal or even greater in women than in men, while men predominate in rectal cancer.
The proportion of malignant bowel cancer in young women is higher than that in men
In addition to tubular adenocarcinoma, a common pathological type of colorectal cancer, the literature reports that the proportion of mucinous adenocarcinoma, indolent cell carcinoma and hypofractionated adenocarcinoma with high malignancy is higher in young women (under 30 years old) than in young men.
Tobacco, alcohol, obesity and hormones may have a greater impact on women
Like male colorectal cancer, the etiology of female colorectal cancer is also caused by dietary factors (high animal fat, high animal protein, high energy and low fiber; deficiency of trace elements such as selenium, zinc, iron, magnesium and vitamins A, C and E; consumption of cured fish, cured meat and fried food), genetic factors (mainly familial adenomatous polyposis and hereditary non-polyposis colorectal cancer), precancerous carcinomas (colorectal adenoma, ulcerative colitis, polyposis), poor lifestyle (lack of physical exercise), and negative life events (e.g., death of a loved one, family discord, interpersonal tension, etc.) are the result of the synergistic effect of multiple adverse factors.
However, there are also some etiological factors that have a greater impact on colorectal cancer in women.
Smoking and alcohol consumption Among female colorectal cancer patients, it was found that the age of onset was 6.3 years earlier in smokers than in women who neither smoked nor drank alcohol, while the corresponding time difference was only 3.7 years in men.
Obesity In premenopausal women, obesity (body mass index ≥30 kg/m2) increases the risk of colorectal cancer by a factor of 1.
Menstrual status Postmenopausal women have a higher risk of colon cancer than premenopausal women. Progressive adenomas Progressive adenomas have been reported in the literature to be malignant to colorectal cancer, and are more likely to occur in women, especially young women, than in men in those who smoke and/or are obese.
Type 2 diabetes and increased serum glycated hemoglobin levels may also increase the risk of colorectal cancer in women.
Effect of treatment for other diseases In patients treated with local radiation for cervical cancer, the risk of subsequent rectal or sigmoid colon cancer increases with the dose of radiation therapy, and the latency period is usually more than 10 years.
Tumor biological behavior is different from that of male patients
The development of colorectal cancer is a complex multifactorial interaction of pathological processes. Genetic analysis shows that colorectal carcinogenesis involves mutations and loss of multiple genes and loci. The most common histological type of colorectal cancer is tubular adenocarcinoma, which accounts for 66.9%-82.1% of all colorectal cancers. The metastasis of colorectal cancer is mainly lymph node metastasis, which can cause enlargement of lymph nodes in the metastasis site (such as abdominal and pelvic lymph nodes). Bloodstream metastasis often occurs in the late stage, and metastasis to the liver is the most common.
However, based on the differences in physiological conditions between genders, some tumor biological behaviors in female patients also exhibit gender specificity. For example, the lower incidence of liver metastasis in female patients compared to male patients may be closely related to the estrogen level in patients. Another study showed that the higher the expression of estrogen receptor (ER) in tumor tissue, the better the prognosis of patients. As for premenopausal female patients, they are more likely to develop ovarian metastasis, which may be related to the rich lymphatic and blood circulation in premenopausal ovaries, which is suitable for the growth of metastatic cancer. In addition, there are also data showing that age ≤50 years, poor tumor differentiation and tumor invasion of the plasma layer are three high-risk factors suggesting the possibility of ovarian metastasis.
Therefore, in addition to the accurate assessment of tumor differentiation, number of lymph node metastases and clinical stage, which reflect the malignancy of the tumor, we should also pay attention to the different physiological status of women as a patient group, which will help us to correctly assess the condition and prognosis of female patients and guide clinical treatment.
Full awareness and comprehensive assessment should be made
Patients with colorectal cancer are usually asymptomatic in early stage, and most of them are not specific even if they have symptoms. Early symptoms of colorectal cancer such as intermittent abdominal pain, constipation or diarrhea, mucus stool, etc. are not specific. Some patients are often misdiagnosed as hemorrhoids, enteritis, dysentery and other diseases that delay treatment.
For female patients, due to the special anatomy of female reproductive system, gynecological diseases may sometimes interfere with the diagnosis of colorectal cancer, and women with lower abdominal pain or abdominal masses may first consider adnexal tumor or inflammation. Women with lower abdominal pain or abdominal lumps may first consider adnexal tumors or inflammation. When symptoms such as blood in stool, abdominal distension, difficult stool, abdominal pain and anemia occur in combination with pregnancy or after pregnancy, they are easily mistaken for pregnancy by doctors and patients under such special conditions. Therefore, clinicians should be fully aware of the complexity of female colorectal cancer symptoms and make a comprehensive assessment, while patients should provide a detailed medical history and cooperate with relevant examinations in a timely manner to avoid delays in diagnosis and treatment.
At present, there are several methods for diagnosis of colorectal cancer.
Rectal finger examination Rectal finger examination is still the most basic and important examination method in the series of preoperative examinations for rectal cancer.
Endoscopy Fiberoptic colonoscopy is the most effective, safe and reliable examination method for the diagnosis of lesions in the large intestine, and most early colorectal cancers can be detected by endoscopy.
Laboratory tests such as fecal occult blood test, hemoglobin test and serum carcinoembryonic antigen (CEA) test.
Imaging and ultrasound examinations such as CT, MRI and ultrasound, etc. For female patients, transvaginal ultrasound is also an ideal test because of the proximity of the vagina to the rectum. Its scanning field of view is larger than transrectal ultrasound, and it can also make accurate localization diagnosis of intestinal stenosis and high rectal lesions that are limited by transrectal ultrasound, which makes up for the limitations of transrectal ultrasound. In addition, vaginal ultrasound during gynecological examination can also be an important way for early detection of asymptomatic rectal tumors.
The influence of gender factor is doubtful.
Although some data show that postoperative survival of female colorectal cancer patients older than 50 years old is longer than that of men, there is no clear evidence that gender has a significant impact on the treatment decision of colorectal cancer patients, so the treatment of female colorectal cancer should still follow the basic principles of colorectal cancer treatment, and different patients should adopt individualized treatment mode due to individual differences.
At present, surgery is still the only radical treatment for colorectal cancer, and most patients can obtain long-term survival after surgical resection. For patients with liver or lung metastases, surgical treatment of metastases can also achieve good results if sufficient liver or lung function is preserved and negative surgical margins are available. For patients with colorectal cancer who have lost the chance of surgery due to late stage or metastasis, neoadjuvant radiotherapy can downgrade the stage of the tumor and even obtain the chance of operability. With the continuous evolution of fluorouracil drugs and the clinical application of oxaliplatin and irinotecan, the chemotherapy regimen for colorectal cancer has been relatively mature and has achieved good clinical efficacy. In recent years, the emergence of molecularly targeted drugs (cetuximab, panitumumab, bevacizumab, etc.) has brought new prospects for the treatment of advanced colorectal cancer, which can not only improve the efficacy of chemotherapy and prolong the survival of patients, but also do not significantly increase the treatment-related toxicity. Of course, the application of some molecularly targeted drugs requires that patients be tested for relevant molecular indicators to predict the efficacy.
Women with colorectal cancer are prone to ovarian metastasis, and prophylactic bilateral oophorectomy should be actively advocated for patients with high-risk factors (histological classification of mucinous adenocarcinoma, mucinous cell carcinoma, hypofractionated adenocarcinoma and Dukes stage C).
In addition, for women, estrogen replacement therapy after menopause can also reduce the incidence of colorectal cancer.
Focus on colorectal cancer prevention
The development process of colorectal cancer is long and there are many studies related to the causative factors. Reasonable dietary arrangement, good lifestyle behavior, strengthening health education on cancer prevention, vigorously promoting regular screening, early detection and removal of precancerous lesions are all of positive significance for the prevention of colorectal cancer.