How does cancer spread through the body? - Ivan Seah Yu Jun

Summary

Cancer metastasis begins when cancer cells spread from the primary tumor to other parts of the body, using pathways like the bloodstream, lymphatic system, or body cavities. This complex process is influenced by various factors, including the cancer’s characteristics and the environment of the metastatic site. Theories like the 'seed and soil' theory and the vascular drainage theory attempt to explain why certain organs are more prone to metastasis. Advances in immunotherapy are showing promise in stopping cancer spread by harnessing the immune system, but many questions remain unanswered in the fight against metastatic cancer.

Takeaways

• 😀 Cancer often begins as a solitary tumor in a specific area of the body.
• 😀 If untreated, cancer can spread to nearby organs and distant areas, such as the brain.
• 😀 The spread of cancer across the body is known as metastasis.
• 😀 Cancer spreads via three common routes: transcoelomic, lymphatic, and hematogenous spread.
• 😀 Transcoelomic spread occurs when cancer cells invade the covering surfaces of body cavities like the peritoneum.
• 😀 Hematogenous spread happens when cancer cells enter blood vessels and travel to distant organs.
• 😀 Lymphatic spread involves cancer cells invading lymph nodes, allowing them to travel to other body parts via the lymphatic system.
• 😀 Once cancer cells reach a new site, they form micrometastases, which can grow into full tumors.
• 😀 Different cancers have specific sites of metastasis, such as prostate cancer often spreading to bones, and colon cancer to the liver.
• 😀 Theories like the seed and soil theory and vascular drainage theory explain metastasis, though both are not entirely conclusive.
• 😀 Immunotherapy, which involves stimulating the immune system, is being explored as a treatment to prevent or stop metastasis.

Q & A

What is the primary cause of cancer metastasis?

Cancer metastasis occurs when cancer cells from an initial tumor spread to other parts of the body, either through nearby tissues or by utilizing the blood, lymphatic, or body cavity systems.

How does cancer spread through the body?

Cancer spreads via three common routes: transcoelomic spread (through body cavities), hematogenous spread (through blood vessels), and lymphatic spread (through the lymphatic system).

What is transcoelomic spread and how does it relate to ovarian cancer?

Transcoelomic spread occurs when malignant cells penetrate the surfaces of body cavities. In ovarian cancer, the cancerous cells spread through the peritoneum, which connects the ovaries to the liver, leading to liver metastasis.

What role does hematogenous spread play in cancer metastasis?

Hematogenous spread involves cancer cells entering the bloodstream, allowing them to travel to distant organs and tissues, facilitating metastasis throughout the body.

How does the lymphatic system contribute to cancer metastasis?

Cancer cells can invade lymph nodes and spread through the lymphatic vessels. As the lymphatic system connects to the bloodstream, it provides a pathway for cancer cells to reach distant sites via hematogenous spread.

What are micrometastases and how do they contribute to cancer progression?

Micrometastases are small clusters of cancer cells that form in new sites after metastasis. These small tumors grow into larger ones, further advancing the cancer’s spread and severity.

What are the two primary theories explaining cancer metastasis?

The two primary theories are the seed and soil theory, which suggests cancer cells only metastasize to environments that support their growth, and the vascular/lymphatic theory, which posits that the site of metastasis is influenced by the drainage of the primary tumor's blood and lymph vessels.

How do the seed and soil theory and vascular/lymphatic theory differ in explaining metastasis?

The seed and soil theory focuses on the cancer cell's compatibility with the microenvironment of a distant site, while the vascular/lymphatic theory emphasizes the role of blood and lymph vessels in directing the spread of cancer cells.

What factors influence the success of metastasis in cancer cells?

Factors such as the cancer cell's properties, the immune system's ability to eliminate cancer cells, and the microenvironment at the metastatic site all play significant roles in determining the success of metastasis.

What recent developments have been made in preventing or treating cancer metastasis?

Recent advancements in immunotherapy, including vaccines to train immune cells to recognize cancerous cells and the use of interleukins to stimulate immune responses, show promise in halting metastasis and improving cancer treatment outcomes.