Can the spread be controlled while targeting one area then treating the next for example?
In: Biology
*ELY5*: it’s not just more of the same thing in different places. The fact that it has spread means **it was likely a worse cancer in the first place (more aggressive).**
*ELY15*: There’s really a lot of reasons. Some more interesting ones:
* **Cancer can change over time and when it spreads:** When cancer moves to new parts of the body, it can change a bit. The more places it spreads to, the more chances it has to become tougher to beat.
* **Treatments work differently in different body parts**: Some cancer medicines are better at reaching certain areas of your body than others. For example, it’s harder for some medicines to get into your brain because of a special barrier. This means doctors might need to use different treatments for cancer in different spots.
* **Hiding cancer cells**: When cancer spreads, it often means there are tiny cancer cells floating around your body that we can’t see. These cells can hide in places where our immune system and cancer medicines have trouble reaching. Sometimes, these hiding cells can pop up years later and start growing again, which is why cancer can come back even after treatment.
* **Treatment limitations**: When cancer is in one spot, doctors can use targeted treatments like surgery, freezing the tumor, or focused radiation. But when cancer spreads to multiple places, they often need to use treatments that affect the whole body. The problem is, these whole-body treatments can cause side effects that build up over time.
*ELY25*:
* **Tumor Evolution and Heterogeneity**: Metastatic sites often differ from the primary tumor. Cancer evolves rapidly, and with more sites comes more opportunities for the cancer to become more aggressive or develop different characteristics. This diversity makes treatment more complex, as what works for one site might not be effective for another.
* **Varied Drug Efficacy in Different Body Parts**: Chemotherapy doesn’t affect all areas of the body equally. Some drugs are better at reaching certain locations than others. A prime example is the blood-brain barrier, which prevents many substances in the blood from entering the brain. This means that a brain metastasis might require different treatment (eg, radiation) than the primary tumor site. Additionally, different locations in the body can have varying environments (eg, different pH levels), which can affect how drugs work.
* **Circulating Tumor Cells and Micrometastases**: When cancer has spread, it means there are circulating tumor cells elsewhere in the body that are difficult to detect and eliminate. These single cells or small clusters can “hide” in various locations, waiting to grow into detectable metastases. While your immune system often destroys many of these cells, some can survive in areas that are less accessible to immune cells or chemotherapy drugs, such as the bone marrow. An illustrative example of this is liver cancer recurrence after transplantation. You might think a liver transplant would be a 100% cure for liver cancer that has not metastasized, but unfortunately, it’s not always the case. A significant portion (about 15%) of patients develop the *same* cancer in their *new* liver. This happens because tiny, circulating cancer cells that were already in the body can eventually make their way to the new liver and start growing again. The larger the original tumor was, the more likely this is to happen, as larger tumors have had more time to release these circulating cells. If you already have metastatic disease outside of the liver, you don’t even qualify for a liver transplant because the recurrence rate makes it not worth it.
* **Treatment Limitations**: When cancer is localized, treatment options often include targeted approaches such as surgical resection, ablation, EBRT, proton therapy, etc. However, metastatic disease necessitates a more systemic approach to treatment. Systemic therapy is limited by cumulative toxicity and the need to maintain the patient’s quality of life.
Latest Answers