Rectal cancer diagnosis and treatment
With the improvement of quality of life, the incidence of rectal cancer is increasing year by year, and it has been reported that the incidence of colorectal cancer (colon cancer + rectal cancer) ranks 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 and rank first. Therefore, research on the diagnosis and treatment of rectal cancer is a very important topic.
Causes
The cause of rectal cancer is still not well understood, and its development is related to social environment, dietary habits and genetic factors. 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 the high risk factors for the development of rectal cancer.
Clinical symptoms of rectal cancer
Early stage rectal cancer is mostly asymptomatic
Patients with progressive cancer (middle and late stage) show symptoms such as abdominal pain, blood in stool, thinning of stool and diarrhea.
1. When rectal cancer grows to a certain extent, blood in stool can appear. A small amount of bleeding is not easily detected by the naked eye, but a large number of red blood cells can be found when the stool is examined by microscope, and the so-called fecal occult blood test is positive. When the amount of bleeding is large, blood in stool with bright red or dark red color can appear. When the cancer surface breaks down and forms ulcers and the tumor tissue is necrotic and infected, pus and blood, mucus and blood stools may appear.
2.Patients may have different degrees of incomplete stool feeling, anal drop feeling and sometimes diarrhea.
3.When rectal tumor causes narrowing of intestinal lumen, symptoms of intestinal obstruction (abdominal pain, abdominal distension, difficulty in defecation) may appear in different degrees. The stool can be thin and with grooves.
4. When tumor invades bladder and urethra, frequent, urgent, painful urination and difficulty in urination may appear; when tumor invades vagina, rectovaginal 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.
5.When the tumor metastasizes distantly (liver, lung, etc.), symptoms may appear in the corresponding organs. For example, dry cough and chest pain may appear when metastasis to lung.
6.Patients may have different degrees of weakness, weight loss and other symptoms.
Patients with the above symptoms (abdominal pain, blood in stool, thinning of stool and diarrhea) are recommended to go to regular anorectal clinics, not to attribute the above symptoms to hemorrhoids, as rectal examination can detect about 70% of rectal cancer. Many patients have delayed treatment because of treating rectal cancer as hemorrhoids.
Pre-surgical examination of rectal cancer
1. Stool routine + occult blood: it can be used as a simple screening index, if the occult blood is positive, further examination is needed
If the occult blood is positive, further examination is needed to understand the condition of gastrointestinal tract (stomach, small intestine, large intestine and rectum).
2.Tumor marker examination: there are two main markers for colorectal cancer: CEA and CA-199.
The positive rate of CEA before surgery is about 30%, and the positive rate of CA-199 in postoperative recurrence is about 70%.
The positive rate of CEA before surgery is about 30%, and the positive rate in postoperative recurrence is about 70%.
3. Patients who do not have problems with rectal examination should not relax their vigilance, and further examination by colonoscopy is feasible to understand the rectum and large intestine that cannot be touched by finger examination.
If the patient is not willing to undergo colonoscopy, he/she should be able to have the colonoscopy. If you do not want to perform colonoscopy, barium enema examination is feasible (note that before performing colonoscopy or
(Note that before performing colonoscopy or barium enema, it is necessary to exclude the presence of intestinal obstruction, and if there is intestinal obstruction, it is prohibited to take laxatives to prepare the intestine).
4, chest X-ray or chest X-ray: exclude the presence of lung metastases
5.Liver ultrasonography or abdominal CT examination: exclude any liver metastasis
6.Pelvic CT or magnetic resonance imaging (MRI) examination to understand the infiltration of tumor and the presence of pelvic lymph node metastasis
7. Anal stool control function test: this test is needed to understand anal stool control function before internal sphincter removal surgery.
Differential diagnosis of rectal cancer
1. Differential diagnosis with hemorrhoids: hemorrhoids are common benign anorectal diseases, and their clinical manifestations are anal mucosal disease and service hours. The clinical manifestation of the disease is that the anal polyps are not only a result of the presence of the polyps, but also a result of the presence of the polyps.
2, and the differential diagnosis of rectal polyps: rectal polyps can also appear with blood in the stool, but generally do not cause abdominal pain, abdominal distension, etc.. It usually does not cause systemic symptoms (such as fatigue, weight loss). The soft mass can be palpated by rectal finger diagnosis, and the finger sleeve can be stained with blood. In contrast, rectal cancer can cause intestinal obstruction and systemic symptoms such as malaise and weight loss. A hard mass can be palpated by rectal palpation, and the finger stains blood.
3. Differential diagnosis with anal fissure: anal fissure is a fissure in the anal canal, which is the result of the time and place of the anus.
Staging of rectal cancer
Stage 0: cancer is limited to the mucosal layer, without lymph node metastasis
Stage I: tumor is confined to the intrinsic muscular layer without lymph node metastasis
Stage II: tumor infiltration beyond the intrinsic muscular layer, but no lymph node metastasis
Stage III: metastasis in lymph nodes
Stage IV: distant metastasis (liver, lung, etc.) or peritoneal metastasis
Treatment options
1.For stage 0 rectal cancer; submucosal cancer with tumor less than 2 cm and mild infiltration: endoscopic mucosal resection (EMR) or transanal endoscopic microsurgery (TEM) can be used, and regular review and follow-up should be paid attention after surgery.
2.For stage 0 rectal cancer with tumor larger than 2 cm, submucosal cancer with deep infiltration, stage II and III cancer, intestinal canal resection + lymph node dissection surgery (D2 or D3) is used
3.For stage IV rectal cancer (rectal cancer with distant metastasis and other conditions)
(1) If both rectal cancer and metastatic cancer can be resected, then surgery is used to remove them
(2) For rectal cancer that cannot be removed by metastases and primary foci, treatment measures other than surgery (chemotherapy, radiotherapy, etc.) are used
(3) For rectal cancer whose metastases can be resected but whose primary foci cannot be resected, treatment measures other than surgery (chemotherapy, radiotherapy, etc.) should be used
(4) For rectal cancer whose metastatic foci cannot be resected but whose primary foci can be resected, surgery can be considered to remove the primary foci and to
(4) For rectal cancer with unresectable metastases but resectable primary foci, surgery can be considered to remove the primary foci, and treatment measures other than surgery can be applied to metastases; for rectal cancer without major bleeding, high anemia, stenosis and perforation, etc.
For rectal cancer without major bleeding, high anemia, stenosis and perforation (metastases cannot be resected but the primary foci can be resected), treatment other than surgery can also be used.
Surgical methods for stage II and III rectal cancer
1. Radical transabdominal rectal cancer surgery (Dixon surgery)
2. Transabdominal rectal cancer resection, distal closure, and proximal fistula (Hartmann operation)
3.Internal sphincter resection (Intersphincteric resection, ISR)
4.Radical abdominal perineal combined rectal cancer resection (Miles’ surgery)
Anal preservation surgery
1. Transanal surgery: suitable for early rectal cancer within 5 cm from the anal verge
2. Trans-posterior approach surgery: suitable for early rectal cancer of 6-9 cm from the anal verge
3. Transabdominal radical rectal cancer surgery: suitable for tumor lower margin distance from anal margin greater than 7 cm (theoretically, this procedure requires tumor lower margin distance from anal margin to be at least 5 cm).
(theoretically, this procedure requires that the distance between the lower edge of the tumor and the anal verge should be at least greater than 5 cm (for early-stage cancer) and at least 6 cm for progressive cancer)
4. Transanal internal and external sphincter rectal cancer resection and colorectal anastomosis: it is suitable for highly and moderately differentiated rectal cancer with the lower margin of the tumor at a distance of 2.5~5 cm from the anal verge, and this procedure is the ultimate procedure to preserve the anus, which can increase the anal preservation rate to 80%.
5. Transabdominal sacral rectal cancer radical surgery: it is suitable for tumor whose lower edge is at a certain distance (6~8 cm) from the anal verge, but it is difficult to operate solely through the abdomen.
If there is difficulty (if the safety of the lower incision line cannot be guaranteed) in primary rectal cancer
Note: Whether the anus can be preserved or not depends on many factors, such as the patient’s gender, age, fatness and thinness, the condition of the tumor, etc. The distance of the lower edge of the tumor from the anus is only a relatively important factor among many factors, and the radicality of the operation cannot be sacrificed for the sake of preserving the anus.
Chemotherapy
1. Postoperative adjuvant chemotherapy for rectal cancer
(1) Whether chemotherapy is needed for stage II rectal cancer is still debated, but it is more recognized that chemotherapy should be performed if one of the following prognostic risk factors is present
Prognostic risk factors for stage II rectal cancer
Pathological aspects
Depth of tumor infiltration into the intestinal wall T4
Number of lymph nodes retrieved Less than 12
Histologic type Hypodifferentiated adenocarcinoma, undifferentiated carcinoma
Vascular invasion Lymphovascular invasion, vascular invasion
Positive tangential line; tangential line less than 2 mm from the tumor, or tangential line status unknown
Clinical findings
Tumor causing intestinal obstruction
perforation of the tumor site
Molecular biology factors: In Japan, two tumor markers, MSI and 18q LOH, are used to help determine whether stage II rectal cancer requires chemotherapy. In China, there is no regulation yet.
(2) For stage III rectal cancer, in principle, chemotherapy should be administered as long as conditions permit.
(3) For stage IV rectal cancer (rectal cancer with distant metastasis, etc.), please refer to the above treatment plan.
Radiation therapy
Radiation therapy has both advantages and disadvantages, see other literature (Luo Chenghua, ed., Colorectal Cancer).
1.Completely resectable rectal cancer
(1) Surgery first, and adjuvant combination therapy including radiotherapy if it is T3 and/or N1-2.
(2) Pre-operative neoadjuvant treatment (radiotherapy or radiochemotherapy), followed by surgery. For patients with ultrasound diagnosis of T3 or clinical T4, postoperative adjuvant combination therapy is added.
(3) Intracavitary radiotherapy alone, mainly for individual early limited tumors.
(4) Local surgical resection combined with radiotherapy, mainly to increase the chance of preserving the anus, can be used for relatively early stage tumors.
2. Incompletely resectable or compound rectal cancer
3. Patients refuse surgery or physical condition does not allow surgery
Note: With the application of total mesorectal excision (TME) technique, there is still a debate on whether postoperative radiotherapy should be performed for completely resectable rectal cancer.
Advantages and disadvantages of preoperative and postoperative chemoradiation therapy
Advantages of preoperative radiotherapy: the primary foci are reduced after radiotherapy, which increases the chance of preserving the anus for surgery; the effect of chemotherapy regimen can be understood; the sensitivity of tumor cells to radiotherapy is improved (the trophoblastic vessels of the tumor are not destroyed by surgery, and the cells are well oxygenated), etc.
Disadvantages of preoperative radiotherapy: it prolongs the waiting time for surgery; due to the possibility of micro metastasis of other organs before surgery, radiotherapy can lead to the low immunity of the body, which may lead to the increase of metastases; it may increase the incidence of postoperative complications; there is a possibility of over-care, etc.
The advantages of postoperative radiotherapy: more precise and individualized radiotherapy can be implemented based on the results of intraoperative exploration and postoperative pathological diagnosis.
Disadvantages of postoperative radiotherapy: the intraoperative operation may cause the small intestine to adhere to the pelvic cavity and thus be damaged by radiation in the process of radiotherapy.
Indications and contraindications of liver resection for rectal cancer liver metastases
Indications for hepatic resection: the patient can tolerate the surgery; the primary foci can be radically resected; the liver metastases can be completely resected; there are no extra-hepatic metastases (such as lung metastases); the residual liver function is good and sufficient to compensate for the lost liver function.
Absolute contraindications to hepatic resection: tumor cannot be completely resected; metastasis to the hilar lymph nodes; extrahepatic metastasis (except for local recurrence, direct infiltration into surrounding tissues, and solitary lung metastasis)
The following conditions need to be carefully performed: 1. technical reasons: all metastases are located near the hepatic vein; metastases are located near the left and right branches of the portal vein. 2. oncological factors (more than 2 factors): more than 5 metastases; metastases over 5 cm in size; simultaneous pulmonary metastases; positive lymph node metastases in the primary focus; high values of tumor markers.
Indications for lung resection for lung metastases from rectal cancer: patients can tolerate surgery; primary foci can be radically resected; lung metastases can be completely resected; no extra-pulmonary metastases (such as liver metastases); good residual lung function, sufficient to compensate for lost lung function.
Contraindications to surgery for local recurrence of rectal cancer
Absolute contraindications: distant metastases cannot be resected; the 2nd sacrum and its proximal sacrum are infiltrated by tumors; intra-abdominal lesions cannot be resected.
Relative contraindications: infiltration of external iliac vessels; radiating pain in the lower extremities; lymphedema of the lower extremities due to tumor; lateral lymph node metastasis; lateral lymph node dissection already performed in the first surgery; elderly patients (>75 years old); combined with more severe circulatory or respiratory system diseases
Prognosis
The overall 5-year survival rate for rectal cancer is about 65.2%, and the 5-year survival rates for each stage are as follows
Stage 0: 93.2%
Stage I: 91,4%
Stage II: 76,4%
Stage III: 58%
Stage IV: 14,6%