Sitting on a bench in the hospital hallway, Auntie Li told me the story of her husband, Lao Zhang, battling cancer. During a routine physical examination half a year ago, Lao Zhang was diagnosed with pancreatic cancer, which shattered the family's peace like a thunderbolt from the sky.
Lao Zhang underwent surgery and underwent standardized chemotherapy. He persevered through the painful treatment process and gave his family hope of recovery. Fate doesn't seem to be gentle on this life-loving runner.
Just a few months later, a sudden, severe headache shattered the tranquility. Lao Zhang was rushed to the hospital, and after an MRI examination, the doctor regretfully told Aunt Li that pancreatic cancer had spread to the brain.
"Who would have thought that cancer would spread so quickly?" The confusion and helplessness in Aunt Li's eyes made me deeply feel the cruelty of this silent war. Her question also led me to think about the mechanism of cancer spread: how did cancer evolve from a small tumor to a systemic threat?
01. The way in which the malignant tumor spreads
Spread through blood vessels: Malignant tumors not only contain a large number of cancer cells, but also form a rich network of neovascularization to provide a continuous supply of nutrients to the tumor.
These blood vessels act as "high-speed channels" for cancer cells, not only transporting nutrients, but also facilitating the spread of cancer cells. About 20% of cancer cells are able to break away from the primary tumor and take the opportunity to "hitchhike" with the blood and travel around the body with the blood circulation.
They are like scattered "seeds", once they find a place in a suitable organ or tissue, they begin to take root, multiply, and form new tumor foci, the so-called distal metastases.
Spread to adjacent organs: Cancer cells are highly aggressive and aggressive, and they can disrupt the connections between normal cells, ignoring the boundaries of the original tissue, and continue to advance into the surrounding healthy tissue.
This process of direct spread is like a cancer cell waging an endless war of aggression at the "border" of the primary tumor. They invade adjacent normal tissues, disrupting their structure and function, and gradually encroaching on the space that would otherwise belong to normal cells.
As the cancer cells continue to spread around, the adjacent organs are gradually invaded, and the function of the organs is impaired, which may eventually lead to the appearance of related symptoms due to the inability to function normally.
Diffusion through lymphatic vessels: The lymphatic system is the body's immune and cleanup network, which is found throughout the body and is closely connected to the circulatory system. Unfortunately, cancer cells have also discovered this hidden "underground passage".
They are able to invade nearby lymphatic vessels and travel upstream, in the direction of lymphatic fluid flow, into the lymph nodes. Once cancer cells "settle" in the lymph nodes, they can multiply rapidly, causing the lymph nodes to enlarge and form metastatic lymph node tumors.
What's more serious is that these cancer cells are not satisfied with staying in one lymph node, they will continue to spread along the lymphatic vessels to the farther lymph nodes or the terminal organs of the lymphatic circulation, such as the spleen and thymus, further spreading the cancer cells and expanding the "invasion territory".
02. The harm of the spread of malignant tumors
Brain metastases: brain metastases may cause severe headaches, often with persistent, paroxysmal exacerbations, and are difficult to relieve effectively with conventional pain medications.
Patients may also experience nausea and vomiting, especially projectile vomiting, because the tumor is pressing on the vomiting center of the brain. Some brain metastases grow rapidly and may cause a sharp increase in intracranial pressure, leading to brain herniation.
Brain herniation is caused by a tumour compressing brain tissue, causing it to shift and squeeze through the cranial sutures into other ventricles, causing severe headache, nausea, vomiting, abnormal pupils, coma, and even death.
Bone metastases: bone metastases often cause severe, persistent bone pain, especially at night or during activity, which severely affects the patient's rest and daily activities.
Metastases destroy bone, making it fragile and prone to pathological fractures. Spinal metastases can cause vertebral collapse, causing compression of the spinal cord or nerve roots, causing numbness, weakness, and even paralysis of the limbs. Metastases from the long bones of the limbs may make it difficult to walk and even require amputation.
Liver metastasis: The liver is an important metabolic center of the human body, and liver metastases can lead to a gradual decline in liver function, manifested as fatigue, loss of appetite, weight loss, jaundice, coagulation dysfunction, etc. As liver function deteriorates, patients may develop serious complications such as hepatic encephalopathy and hepatorenal syndrome.
Liver metastases can cause pain in the upper right abdomen, bloating, and sometimes radiating to the back. When the tumor is large, the patient may feel a lump in the liver.
The treatment of liver metastases is usually more complex than that of primary liver cancer, and may require a combination of surgery, intervention, radiotherapy, targeted drugs, immunotherapy, etc., and the efficacy may be inferior to that of primary liver cancer.
In the face of the daunting challenge of cancer spread, we must recognize that early detection and early treatment are key. In particular, close monitoring of high-risk populations and cancer survivors.
It can capture the clues of tumor spread in the first time, and gain valuable time for subsequent treatment. Actively promoting a healthy lifestyle is an effective measure to prevent the spread of cancer.
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