How to prevent recurrence and metastasis of rectal cancer surgery

In my country, rectal cancer accounts for about 60% of colorectal cancers, and the 5-year survival rate after radical surgery is 50 to 60%. The main reasons for treatment failure are local recurrence and distant metastasis. Local recurrence may be a major factor in recent death after rectal cancer surgery. About 80% of patients die from local recurrence without distant metastasis. Literature reports that the local recurrence rate of rectal cancer is between 12.7 and 31%. It can be seen that preventing local recurrence after radical surgery for rectal cancer has important clinical significance for improving the survival rate of rectal cancer.

Complete radical resection of the tumor and lymph node dissection are the key to preventing local recurrence after rectal cancer surgery

In addition to the main factors such as the pathological type of the tumor itself, the degree of differentiation of tumor cells, the size and location of the tumor, lymph node metastasis and staging, the operation during surgery plays an important role in tumor recurrence. The local recurrence rate after surgery is 15.7% [abdominoperineal resection (APR) recurrence rate is 16.9%, and low anterior resection (LAR) recurrence rate is 14.3%. We have realized that in order to reduce the local recurrence rate after rectal cancer surgery, it is very important to completely remove the tumor and lymph node dissection.

One of the reasons for the high perineal recurrence rate after Miles surgery for low rectal cancer is that the radical resection of the tumor is not enough. In many hospitals, when performing Miles surgery, the perineal incision is only performed along the perianal area, anal canal, and rectal wall, and the pararectal pelvic tissue is not cleared. The perineal wound is sutured at the end of the surgery, and the perineal wound is healed in the first stage when the patient is discharged from the hospital. This actually greatly increases the chance of local recurrence of the perineum. In addition, the use of paraanal muscles to replace sphincters for anoplasty for low rectal cancer has been proven to increase the local recurrence rate due to insufficient tumor resection, which is also undesirable. Considering the influence of surgical operation technology, the author believes that the following issues need to be paid attention to during the operation to avoid local recurrence of the perineum and pelvis caused by it. Low rectal cancer, especially invading the anal canal or anal canal cancer, the extent of resection of the tissues around the anus and rectum is crucial to the recurrence of perineal tumors. The scope of perineal skin incision: The midpoint of the line from the ischial tuberosity to the anal margin is the two sides of the skin incision mark, the front cutting edge should be at the midpoint of the line from the root of the scrotal frenulum to the anal margin (for women, the midpoint from the posterior labia majora to the anal margin), and the rear cutting edge is at the tip of the coccyx. The above marks form an elliptical skin incision around the anus. After the skin is cut, the subcutaneous fat should be removed as much as possible along the incision obliquely to both sides, so as to ensure that the surgical cutting edge is at least 3 cm away from the tumor, and the tissue in the perianal lymphatic drainage area is removed.

The lateral rectal ligament, levator ani muscle and anococcygeus ligament should be cut as close to the pelvic wall as possible, especially the tissue around the base of the tumor, and the resection range should be expanded. In this way, the abdominal and perineal radical specimens of rectal cancer separated from the abdominal cavity are completely removed, forming a perineal defect. The author's experience is that the defect area formed after perineal resection after Miles surgery should at least accommodate a space as big as the surgeon's fist. It is absolutely not possible to expect the perineal wound to heal in the first stage and retain too much perianal skin and subcutaneous tissue. If only a small circular incision is made along the perianal area and very little perineal and pelvic tissue is removed along the rectal wall, the radical significance of Miles surgery is lost, and the opportunity for postoperative perineal recurrence is buried.

Radical resection of rectal cancer is to completely remove the mesorectum by sharp separation during pelvic separation, i.e. the surgical principle of "total mesorectal excision" (TME), which is of great significance not only for mid-upper rectal cancer, but also for abdominoperineal resection of low rectal cancer, in reducing the local recurrence rate. In the 152 cases reported, radical anterior resection was performed according to the TME principle, of which 42 cases had a distal resection of less than or equal to 1 cm and no recurrence after surgery, and only 4 cases had recurrence among the 110 cases with a distal resection of more than 1 cm, indicating that the key to reducing the local recurrence rate is not the length of the cut end, but the scope of mesorectal resection.