What we need to know about the spread of cancer (metastasis) – simply explained

What you need to know about cancer spread (metastasis) – explained simply

This text explains why and how cancer spreads in the body (a process called metastasis) and how researchers are trying to stop this phenomenon. Think of cancer cells as seeds trying to grow in new places in the body, far from the initial tumor.

Why is it important to understand metastasis?

When cancer spreads to other organs, such as the brain, lungs, or bones, it becomes much more dangerous and is a major cause of death. That’s why researchers, inspired by patient experiences, are intensely studying this process.

How do cancer cells manage to spread and survive?

• A difficult journey: For a cancer cell, it is very difficult to survive in the bloodstream and adapt to a new environment, such as another organ. That’s why not all cells that detach from the initial tumor manage to form a new tumor (metastasis).
• Amazing adaptation: The cells that do manage to form metastases are special. They are very flexible and can change the way they “feed” (their metabolism) to suit the new environment and the available nutrients there.

What have recent studies discovered?

• Preferences and resistance: It seems that original tumors have “preferences” for certain places to send cells. Interestingly, some parts of the body, such as the spleen or muscles, seem to be more resistant to the appearance of metastases, due to their specific way of functioning.
• Preparing the ground: Cancer cells can “prepare” the place they will reach from a distance. They do this by sending chemical “messages” or even with the help of bacteria in the gut, which can influence the environment in other organs.
• The role of fats: The type of fats (fatty acids) in tissues can help or hinder the growth of metastases. For example, this has been observed in lung metastases and in experiments on the brain.

Cancer cells are surprisingly “ingenious” when it comes to surviving in difficult conditions in the body, far from the initial tumor. Think of them as highly adapted explorers trying to colonize new and sometimes unfriendly territories. Here are some ways they achieve this, based on the previous information:

1. Flexibility in “Feeding” (Metabolic Adaptation): Cancer cells that spread (metastatic) are very flexible in terms of the “food” they consume. They can change their metabolism (how they process nutrients) to match what they find in the new environment. For example, if there isn’t much sugar (glucose) in a place, they can try to use other energy sources. This adaptability helps them survive in diverse nutritional conditions.
2. Preparing the Ground from a Distance: Sometimes, cancer cells can “prepare” a new organ before they arrive there. [3] They do this by releasing certain chemicals (signaling molecules) that modify the environment in that organ to make it more hospitable. [3] Even bacteria in the gut can play a role in influencing these distant environments.
3. Exploiting Local Resources:
   • Fats: The composition of fatty acids (a type of fat) in tissues can help cancer cells grow in the new location.
   • Iron: In nutrient-poor environments, such as spinal fluid (the fluid around the brain and spinal cord), metastatic cancer cells seem to rely heavily on iron to survive. This is a vulnerability that researchers hope to exploit with treatments that remove iron.
4. Defense Against Attacks:
   • Oxidative Stress: During their journey through the body and settling in a new location, cancer cells face harmful substances (reactive oxygen species or “free radicals”) that can kill them. Some cancer cells, especially those in lymphatic environments, develop defense mechanisms to survive this “oxidative stress.”
   • Immune System: Although the immune system fights against cancer cells, some cells manage to evade detection or resist immune attacks. Sometimes, cancer cells can even “tire out” immune cells.
5. Entering a State of “Dormancy” (Hibernation): Some research suggests that cancer cells can enter a state of “dormancy” or hibernation to survive unfavorable conditions or to hide from treatments. Later, when conditions become better, they can “wake up” and start growing again.
6. Genetic Changes and Specific Adaptations: Cancer cells can undergo genetic changes that help them survive in low oxygen conditions (hypoxia) or when there aren’t enough nutrients. These adaptations can also make them more invasive.

It is important to note that survival in the bloodstream and colonization of a new organ are very difficult processes for cancer cells, and only a small fraction of them succeed. However, those that do succeed have these remarkable capabilities of adaptation and survival. Understanding these mechanisms is crucial for developing new treatment strategies that target these “tricks” of cancer cells.

Can diet influence metastasis?

• Impact of diet: Yes, what we eat can influence the risk of metastasis. For example, certain fatty acids (polyunsaturated) could make cancer cells easier to destroy.
• Be careful with antioxidants: Although we think antioxidants are always good, in some situations they could actually help cancer cells survive. This shows how complicated the link between diet and cancer is.

What does all this mean for treatment?

By understanding how cancer cells adapt and cope with stress, researchers hope to develop new treatments. The idea is to find the “weak points” of these cells or make their life so difficult that they can no longer survive and form new tumors in other organs.

Although diet can play a role, more studies are needed to understand exactly how we can use diet in the fight against cancer spread.

Source Medscape