Correct understanding of the concept of middle and low rectal cancer The usual classical anatomical definition of rectum is the area within 15 cm from the anus as rectum. According to this classification, the rectum is divided into upper rectum (11-15 cm from the anal verge), middle rectum is 6-10 cm, and lower rectum cancer is 0-5 cm. Lower and middle rectum cancer is tumor occurring in the rectum from the anal verge to 10 cm. Emphasizing the concept of mid-lower rectum has important clinical implications for treatment. This is because both international and national clinical guidelines have clearly stated that treatment of mid-low rectal cancer requires clinical evaluation and that preoperative radiotherapy is required for locally progressive rectal cancer. Standardized preoperative staging and necessary neoadjuvant treatment For the treatment of rectal cancer, standardized preoperative staging and necessary neoadjuvant treatment can reduce the difficulty of anus-preserving surgery and local recurrence rate of low- and middle-grade rectal cancer. In our clinical work, we found that, from the root analysis, many cases with irregular treatment are not preoperative staging. In particular, standardized preoperative staging is crucial when performing anus-preserving surgery for low- and mid-level rectal cancer. At present, from the international literature, preoperative staging mainly adopts the TNM staging of the American Cancer Society (AJCC). It is internationally recommended to apply MRI of the pelvis and transrectal ultrasound examination of the vulgar spirits system to brag about nettle 6 miscellaneous enjoined plant compulsions to haunt the back of Π乇鹗侵械臀恢背ΠcT3 (c means clinical stage), cT4, or patients with lymph node metastasis should receive preoperative neoadjuvant radiotherapy. Radiotherapy doses of 45.0 to 50.4 Gy for 25 doses are usually chosen. Chemotherapy is either oral capecitabine or continuous intravenous 5-FU. The benefits of preoperative neoadjuvant radiotherapy have been demonstrated to reduce the rate of local recurrence and increase the chance of anal preservation. Standardized preoperative staging and adjuvant treatment for low and intermediate rectal cancer are important issues facing rectal cancer surgery in China that need to be addressed in a standardized manner. Scientific and standardized preoperative staging and appropriate application of preoperative neoadjuvant therapy can significantly reduce the local recurrence rate and enable patients to benefit from neoadjuvant therapy. Reasonable choice of anus-preserving surgery For the surgery of low and middle rectal cancer, anus-preserving surgery has always been an important treatment means to improve patients’ quality of life. Many patients also have a strong desire to preserve the anus. However, for anal preservation surgery, although a variety of surgical techniques have been reported, including ultra-low anastomosis methods such as colo-anal anastomosis, the key is the preservation of anal sphincter function after anal preservation surgery. It is very common for some patients to have poor postoperative patient quality of life and poor bowel control despite the use of low and especially ultra-low anastomoses. Therefore, surgeons should be realistic when choosing anus-preserving surgery, and choose it reasonably according to their own operating techniques and the patient’s own characteristics. The difficulties that an unsuccessful anal preservation surgery can bring to the patient’s postoperative life are incalculable. It is disastrous for the patient if the anus is only preserved but not the complete sphincter function, which should be highly valued by the surgeon. Key points to note during surgery 1. Distal margin problem: The key to the surgery of low and middle rectal cancer is radical treatment to reach R0 resection. During the operation, especially for obese male patients, the exposure of distal incision margin and safe incision margin are very important due to the relative narrow pelvis. A recent Meta-analysis of 7000 patients showed that the difference in local recurrence rate between distal margins >1 cm and ≤1 cm was only 1% and was not statistically significant (P > 0.05). Recent literature suggests a change in the importance of the distal margin and its perception for low anal preservation surgery for rectal cancer. More prospective clinical trials are needed to confirm whether the traditional 2 cm safety margin still has real clinical significance. 2. Importance of circumferential margin: In low anal preservation surgery, in addition to the distal margin, the circumferential margin is crucial. Preoperative neoadjuvant therapy is recommended for patients with a potentially positive preoperative assessment of the circumferential margin. In contrast, postoperative adjuvant chemotherapy is recommended for patients with a positive postoperative pathologic assessment of the circumferential margin. In the absence of preoperative neoadjuvant therapy, patients with positive circumferential margins should receive postoperative adjuvant radiotherapy. Therefore, there is a shift in the surgeon’s perception from adequate distal margins to a focus on the circumferential margins. Prevention and treatment of anterior resection syndrome Anterior resection syndrome is an important complication of anus-preserving surgery for low rectal cancer, which refers to a number of symptoms caused by frequent and urgent stools and difficult stool control after anus-preserving surgery for low rectal cancer. The incidence of anterior resection syndrome after anorectal preservation surgery for low rectal cancer is high, especially for patients with colorectal anastomosis, the incidence is as high as 30%. Patients with anterior resection syndrome often have poor quality of life and frequent defecation, which makes patients suffer. For patients who undergo anal preservation surgery for low to medium rectal cancer, especially for patients with low anastomosis or ultra-low anastomosis, effective preoperative doctor-patient communication is very important. First of all, we should fully explain the possible complications of ultra-low anastomosis, including anterior resection syndrome, and obtain the full understanding of patients. In addition, there is no standardized treatment protocol for the prevention of anterior resection syndrome. For ultra-low colonic anastomosis, a colonic storage bag can delay or reduce the symptoms of anterior resection syndrome. The length of the colonic storage pouch does not exceed 5 cm, and the colonic storage pouch can function better in the first 1-2 years after the surgery to control the stool. There is no uniform quality control standard for complication control of anal preservation surgery. Symptomatic treatment is the main countermeasure. Usually, stool regulation by diet is used, and the use of some drugs is only expedient. In our clinical work, we often encounter some patients who have already undergone local resection for rectal cancer in local hospitals, and the most common points of these surgeries are: 1. 2. Most of the resected pathological specimens were not standardized for labeling, which made the pathologists unable to judge whether the patient’s resection margins were clean. According to the requirements of the U.S. National Comprehensive Cancer Network guidelines and the 2011 edition of the Chinese colorectal cancer diagnosis and treatment standard of the former Ministry of Health, local resection of rectal cancer needs to meet the following points: 1. stage T1 tumor; 2. better differentiation; 3. MRI indicates no enlarged lymph nodes; 4. <8 cm from the anus; 5. tumor diameter <1/3 of the total length of the intestinal circumference; 6. cutting edge >3 mm; 7. endoscopically resected Thus, it seems that there are strict indications for local resection of rectal cancer. In addition, a common question is how to deal with preoperative evaluation of stage T1 tumor, but postoperative pT2, or positive cut margins? Many surgeons use the approach of extended resection, but in fact the guidelines have clearly stated that such patients should not undergo extended resection because the probability of distant or regional lymph node metastasis in such patients (especially those with pT2) is much higher than that of stage T1 tumors. The correct choice is to perform radical rectal cancer surgery. For low and intermediate rectal cancer, how to choose a reasonable surgical approach should take into account the maximum benefit for the patient, firstly to achieve the goal of radical treatment, and then to consider preserving the function of the anal sphincter. Starting from preoperative staging, standardizing the preoperative treatment and choosing the surgery reasonably will bring benefits to patients with low- and intermediate-level rectal cancer.