The incidence of colorectal cancer is increasing year by year, and the incidence of colorectal cancer (colon cancer + rectal cancer) has been reported to rank third (the first two are lung cancer and gastric cancer), and by 2015 the incidence of colorectal cancer may exceed that of lung cancer and gastric cancer, ranking first.
I. Causes
The cause of colorectal cancer is still not very clear, and its incidence is related to social environment, dietary habits, genetic factors and so on. Colorectal polyps are also a high risk factor for colorectal cancer. It is basically recognized that high intake of animal fat and protein and insufficient intake of dietary fiber are the high risk factors for colorectal cancer.
Clinical manifestations
1.Most early colorectal cancers are asymptomatic.
2.Patients with progressive cancer (middle and late stage) show symptoms such as abdominal pain, blood in stool, thinning of stool and diarrhea.
3.Colorectal cancer can appear blood in stool when it grows to a certain degree.
4.Patients may have different degrees of incomplete stool feeling, anal drop feeling and sometimes diarrhea.
5.When colorectal tumor causes narrowing of intestinal lumen, symptoms of intestinal obstruction (abdominal pain, abdominal distension, difficulty in defecation) may appear in different degrees, abdominal pain and bowel sound before defecation, and the symptoms will be reduced after defecation. The stool can be thin and with grooves.
6.When tumor invades bladder and urethra, frequent, urgent, painful urination and difficulty in urination may appear; when tumor invades vagina, colorectovaginal fistula and fecal fluid may appear; when tumor invades sacrum and nerves, severe pain in sacrococcygeal area and perineum may appear; when tumor invades and presses ureter, swelling and pain in lumbar area may appear; when tumor also presses external iliac vessels, edema of lower limbs may appear. All the above symptoms indicate that the tumor is in advanced stage.
7.When the tumor metastasizes distantly (liver, lung, etc.), the corresponding organs may show symptoms. For example, dry cough and chest pain may appear when metastasis to lung.
8.Patients may have different degrees of weakness, weight loss and other symptoms.
For patients with the above symptoms (abdominal pain, blood in stool, thinning of stool and diarrhea), it is recommended to go to regular anorectal clinics, not to attribute the above symptoms to hemorrhoids, as colorectal diagnosis can detect about 70% of colorectal cancer. Many patients delay treatment because they treat colorectal cancer as hemorrhoids.
III. Treatment
Examination: colonoscopy
Treatment: mainly includes surgery, chemotherapy, radiotherapy, biological targeted therapy, etc.
Surgery: According to different stages, surgery can be open surgery or minimally invasive surgery.
Colorectum has its unique anatomical characteristics: there is no peritoneal coverage in the colorectum below the peritoneal reflex, so there is no colorectal mesentery, so locally advanced colorectal cancer below the peritoneal reflex (T3/T4 stage) is easy to invade the extra-intestinal wall tissues, and the local recurrence rate is high after surgery. Therefore, the best treatment mode for such patients is preoperative neoadjuvant radiotherapy followed by surgery.
Advantages of preoperative radiotherapy.
1. reduction of the primary focus after radiotherapy, which increases the chance of preserving the anus for surgery.
2.The effect of chemotherapy regimen can be understood.
3.Improve the sensitivity of tumor cells to radiotherapy, etc.
4.To achieve the effect of tumor down-staging.
5.Reduce the local recurrence rate.