What are the treatment options for colorectal cancer?

As the incidence of colorectal cancer increases year by year, various new technologies and new treatments continue to emerge. However, as far as the current situation is concerned, surgery is still the most effective way to treat colorectal cancer. The basic principles of colorectal cancer surgery are consistent with the basic principles of tumor surgery. In summary, they are the three principles of radicality, safety, and functionality.

Surgical methods for colorectal cancer: 1. Local resection: Local resection refers to the removal of part of the intestinal wall in the area where the tumor is located. It is suitable for early superficial colon cancer and benign tumors that are limited to the mucosa or muscularis mucosa. Some malignant tumors located in the muscularis mucosa and the submucosa may have regional lymph node micrometastasis and metastasis in a few cases. Local resection alone may not meet the requirements of radical cure. Such cases should be used with caution. The scope of local resection can include the entire layer of the intestinal wall, and the cutting edge is far from the tumor. It can also be performed by endoscopy to remove the mucosa, submucosa and part of the muscularis mucosa. 2. Intestinal segment resection: Intestinal segment resection refers to the removal of a certain length of the intestinal tube including the tumor. Generally, the upper and lower cutting edges are required to be far from the tumor. The resection of the tumor intestinal segment should include the corresponding mesentery resection, that is, to meet the DL requirement. It is suitable for larger benign tumors and cancers that are partially limited to the submucosa and superficial muscularis without lymph node metastasis. . Radical surgery: Radical surgery or absolute radical surgery refers to the complete removal of the tumor and the removal of regional lymph nodes, and there is no cancer residue at each resection margin in histological examination. . Combined organ resection: Combined organ resection for colon cancer is suitable for cases with invasion of adjacent organs and is often used as a radical surgical procedure. However, in some cases, such as when the tumor invades other organs, obstruction or perforation may occur, or internal fistula has formed, and the survival expectation after surgery is long, even if distant metastasis has occurred, palliative combined organ resection can still be performed. E. Palliative tumor resection: Absolute palliative tumor resection refers to cases where there is tumor residue visible to the naked eye. For example, if there is metastasis to the peritoneum, liver, and non-regional distant lymph nodes, it is impossible to remove all metastatic lesions. Relative palliative tumor resection or relative radical surgery, although it is a radical surgical procedure, the tumor has been completely removed by naked eye during the operation, but postoperative histology confirms that there is a resection margin, tumor base residue, or metastasis in the highest level lymph nodes removed.

According to the nature and purpose of treatment, radiotherapy can be divided into radical radiotherapy and palliative radiotherapy. The status of preoperative radiotherapy in the comprehensive treatment of rectal cancer has been gradually affirmed.

Therefore, how to prevent and treat local recurrence remains the focus of colorectal cancer research. At present, although the reports on the efficacy of postoperative radiotherapy are inconsistent, combined radiotherapy and chemotherapy after rectal cancer surgery is still the standard adjuvant treatment method. It is generally believed that the earlier the postoperative radiotherapy starts, the better the effect, and it is best to start within 2 months after surgery. Since the local recurrence rate after surgery is low for stage I patients, there is no need to add radiotherapy. Patients in stages II and III, especially those with obvious extralesional invasion, more regional lymph node metastasis, and local residual after surgery, often require postoperative radiotherapy.

In recent years, this method has been used less frequently because of the long interval between treatments, lack of integrity, and difficulty in controlling radiation doses. Squamous cell carcinoma is sensitive to both radiotherapy and chemotherapy, and chemotherapy drugs such as 5-FU, mitomycin, and cisplatin have been shown to have radiosensitization effects. In view of this, "radiotherapy and chemotherapy" has become the preferred treatment for anal squamous cell carcinoma in Europe and the United States, and has achieved good results.

The results of a group of randomized trials showed that the mortality rate and complications of preoperative radiotherapy were equal to zero. If the basic principles of radiobiology such as fractionation, fractionated dose, and dose-volume effect can be fully followed during radiotherapy, there will be almost no complications of preoperative radiotherapy, and it will not increase the complications of postoperative patients due to preoperative radiotherapy. Postoperative radiotherapy can cause perineal scar hardening or mild enteritis and cystitis, which can generally be relieved after symptomatic treatment.

After radical resection of colorectal cancer, patients may have recurrent or metastatic tumors in a single site and may need radical resection again. For local recurrence, the decision of whether to have another surgery and the method and scope of surgery should be determined based on the extent of the lesion. For patients with liver metastasis who have no recurrence or metastasis to other sites except the liver, and for patients with lung metastasis who have no recurrence or metastasis to other sites except the lung, the number and scope of metastatic lesions will determine whether surgery can be performed, and chemotherapy and other comprehensive treatments will be used. Generally. Therefore, if liver and lung metastatic cancers are found during follow-up, surgical resection should be sought depending on the situation. For those who cannot be resected, if chemotherapy is effective, some patients may still have the opportunity to be resected and cured.

The liver is the most common metastatic site of colorectal cancer and is limited to the liver. Although previous literature has reported that the prognosis of liver metastasis is very poor, the treatment of lung metastasis is still not clear.

The lung is also one of the most common sites for extra-abdominal metastasis of colorectal cancer. Among all colorectal cancers, lung metastasis is often accompanied by systemic metastasis. X-ray examination can provide valuable information for the diagnosis of lung metastasis, CT examination can correctly estimate the number and location of lung lesions, fiberoptic bronchoscopy brush or needle aspiration biopsy can clarify the pathological type, and sputum cytology examination can also provide reference, but the positive rate is low.