Rectal cancer is cancer between the dentate line and the junction of the rectosigmoid colon, and is one of the most common malignant tumors of the gastrointestinal tract. The location of rectal cancer is low, so it can be easily diagnosed by rectal finger diagnosis and colonoscopy. However, because of its location deep into the pelvic cavity and close relationship with the adjacent organs, it is more difficult to operate. The preservation of anal function in the anal preservation surgery of low rectal cancer is closely related to the postoperative quality of life.
Etiology
Its development is related to social environment, dietary habits, genetic factors, etc. Rectal polyps are also a high-risk factor for rectal cancer. It is basically recognized that high intake of animal fat and protein and insufficient intake of dietary fiber are high-risk factors for the occurrence of rectal cancer. In addition, red meat (such as pork, beef and lamb) is also considered a risk factor for the development of rectal cancer.
Clinical manifestations
Most of the early rectal cancers are asymptomatic, but when rectal cancer grows to a certain extent, there are changes in bowel habits, bloody stools, pus-blood stools, urgency and heaviness, and gradually thinning of stools, and in advanced stage, there are obstruction of bowel movement, emaciation and even cachexia. When the cancer invades the bladder, urethra, vagina, prostate and other surrounding organs, corresponding symptoms will appear.
Examination
1.Anal examination
Anal examination during physical examination is a simple and effective method to detect rectal cancer. The majority of rectal cancer is low to medium level cancer, which can be palpated by the patient during consultation. Pus and blood can be seen in the finger set.
2.Colonoscopy
Abnormalities of the colon and rectum can be detected, and sometimes multiple tumors of the colon and rectum can be detected, and biopsies can be obtained under the microscope, and pathology can confirm the nature of the disease.
4.Pelvic magnetic resonance examination (MRI)
To understand the relationship between the tumor and the surrounding adjacent organs, to assess the lymph node metastasis, to carry out preoperative clinical staging, and to formulate a reasonable strategy for comprehensive treatment, whether to operate first or radiotherapy, or chemotherapy first? Evaluate the possibility of preserving the anus.
5.CT of abdominopelvic cavity
To evaluate whether there are metastases around the rectum and other parts of the abdominopelvic cavity. It is not as sensitive as MRI for clinical staging of rectal cancer.
6.CT of chest or chest X-ray
To understand whether there is metastasis in lung, pleura, mediastinal lymph nodes, etc.
Treatment
The treatment of rectal cancer requires a comprehensive treatment mainly based on surgery and supplemented by chemotherapy, radiotherapy and targeted therapy.
1.Radical surgery
(1) Combined transabdominal perineal resection (Miles surgery)
The scope of resection includes the sigmoid colon and its mesentery, rectum, anal canal, anal raphe, the tissues in the colorectal fossa and the skin around the anus, and the blood vessels are severed by high ligation of the inferior mesenteric artery or ligation below the left colonic artery division, and the corresponding para-arterial lymph nodes are cleared. A permanent colostomy (artificial anus) is made in the abdomen. This procedure was previously considered to be a complete resection with a high cure rate.
(2) Transabdominal low resection and extraperitoneal one-stage anastomosis
Also called prerectal resection (Dixon procedure), the sigmoid colon and large part of the rectum are resected intraperitoneally, the rectum below the retroperitoneal fold is freed, and the sigmoid colon and rectum are anastomosed extraperitoneally. This operation is less damaging and can preserve the original anus, which is more ideal. With the improvement of surgical technology, the application of laparoscopic surgery, and the innovation of surgical concept, many anus-preserving surgeries have been successfully carried out, which has brought good news to patients.
2.Palliative surgery
If the local infiltration of cancer is serious or metastasis is extensive and cannot be cured, in order to relieve the obstruction and reduce the patient’s pain, palliative resection is feasible by making limited resection of the intestinal segment with cancer, sewing up the distal rectum and taking the sigmoid colon for stoma (Hartma surgery). If this is not possible, only sigmoid stoma will be performed, especially in patients with intestinal obstruction.
3.Radiotherapy
Radiotherapy plays an important role in the treatment of rectal cancer. At present, it is believed that the survival period of preoperative simultaneous radiotherapy followed by surgery is longer than that of surgery followed by radiotherapy for low to medium rectal cancer with late local staging.
4.Chemotherapy
Postoperative chemotherapy is recommended for patients with high risk stage II and III pathological staging of rectal cancer, and the total chemotherapy time is six months. Chemotherapy can also be placed before surgery to make the tumor shrink before surgery.
Prognosis
Rectal cancer can be treated by active surgery, supplemented by regular chemotherapy or and radiotherapy after surgery, and most of them can obtain satisfactory results.
Prevention
Patients with family history of tumor should have regular colonoscopy, and healthy people should be encouraged to have colonoscopy to detect benign rectal masses and treat them endoscopically to avoid malignant transformation.