Metastasis refers to the intestinal cancer cells that invade the lymphatic vessels, blood vessels or other routes from the primary site and are taken to other places to continue to grow, forming the same type of tumor as the primary tumor, this process is called metastasis, and the resulting tumor becomes metastasis or metastatic cancer. Metastasis is a feature of worsening colorectal cancer and is the leading cause of death in colorectal cancer patients.
Lymphatic metastases: lymphatic metastases generally spread sequentially from near to distal along the vascular side innervating the colorectum, but there are also sequential transboundary metastases. As the tumor penetrates deeper into the intestinal wall, or even penetrates the intestinal wall, there is a greater chance of lymphatic metastasis, which is manifested by CT imaging or pathological examination suggesting lymph node metastasis. Unlike regional lymph node metastases near the tumor, lymph node metastases far from the tumor site are classified as distant metastases.
Blood metastasis: After intestinal cancer cells invade small blood vessels or fall off from tumors, they can pass through the human blood flow system, first reach the liver (most common), and then reach other tissues and organs such as lungs, brain, and bones. Some patients will have occult distant metastases that cannot be detected by B-ultrasound or CT, which is manifested as no metastasis in preoperative examination, but distant metastases are found within six months after surgery.
Invasion and implantation: Cancer can directly invade surrounding tissues and organs. Cancer cells shed in the intestinal lumen and can be implanted on the intestinal mucosa elsewhere, and falling in the abdominal cavity can lead to multiple metastases in the abdominal cavity, causing ascites and intestinal obstruction.
The traditional belief that distant metastasis of colorectal cancer is impossible, resulting in some patients or their families often choosing to be passive or even give up after knowing that colorectal cancer has metastasized in the distance, which is undoubtedly tragic.
In recent years, with the update of metastasis resection concepts and medical technologies, as well as the development and application of new chemotherapy drugs, targeted drugs (such as cetuximab, bevacizumab, etc.) and immunological drugs (such as PD-1 inhibitors), more and more patients with distant colorectal metastases have a chance of long-term survival or even the best opportunities. At present, the most innovative innovations in distant metastasis in colorectal cancer patients are reflected in the following points:
Regardless of the number of metastases, as long as complete resection can be obtained, patients have the possibility of long-term survival, and even the best chance. Some patients have colorectal cancer or metastases that cannot be completely resected initially, but through systemic chemotherapy combined with targeted **, the chance of surgical resection is finally obtained, which further improves survival and even obtains the chance of **. Patients with distant metastases of colorectal cancer who have lost the chance of ** can also improve their overall survival and prolong their survival through a series of comprehensive ** (such as chemoradiotherapy, intervention**, targeting**, enterostomy surgery, etc.). Others: Multidisciplinary Discussion (MDT) mode of colorectal cancer, precision ** and individualized diagnosis and treatment mode of cancer based on genetic testing**, also known as multidisciplinary discussion (MDT) is an effective means for the diagnosis and treatment of metastatic colorectal cancer, and many international guidelines recommend that such patients enter the MDT ** mode.
In the traditional model, the patient's regimen is influenced by the department or doctor who first sees the patient. If the surgeon is the first to receive the patient, the priority is whether the tumor can be removed surgically, and if it cannot be removed, it is usually transferred to the medical oncology department for chemotherapy or radiotherapy in the radiation oncology department. If the interventional physician receives the patient, the first consideration is whether the tumor can be partially intervened** - in this process, the patient is referred multiple times, and the examination is repeated, which is easy to delay the disease. In addition, with the development of specialization and the improvement of doctors' professional level, the limitations of thinking mode and knowledge field will have an adverse impact on patients, which is manifested in the fact that patients and their families find themselves faced with a variety of different choices after listening to the opinions of experts in internal medicine, surgery, radiotherapy, etc., and it is difficult to weigh the advantages and disadvantages.
The emergence of the MDT diagnosis and treatment model solves the above problem well. Once a patient enters the MDT treatment mode, he is not only faced with a doctor, but also a diagnosis and treatment team, including doctors from multiple departments that may be involved in his or her disease. The team worked together to develop a standardized protocol that minimized misdiagnosis and mistreatment of patients.
Multidisciplinary expert discussion (the Colorectal Cancer Multidisciplinary Team Outpatient Clinic of Zhongshan Hospital Affiliated to Fudan University is led by the Department of Colorectal Surgery and jointly with the chief physician and deputy chief physician of multiple departments related to colorectal tumors, such as liver surgery, thoracic surgery, chemotherapy (medical oncology), radiotherapy, interventional surgery, imaging (i.e., radiology, including nuclear medicine), pathology, etc., to discuss difficult cases such as colorectal tumors and formulate the best individualized plan for patients).