Cancer medicine is a specialized field that treats cancer with drugs and other substances. It uses diverse treatment approaches tailored to the specific cancer and individual patient. As the understanding of cancer’s biology deepens, treatment methods are advancing. This evolution leads to more precise and effective ways to manage the disease, shifting from generalized treatments to personalized strategies.
Chemotherapy
Chemotherapy uses cytotoxic drugs to kill or slow the growth of rapidly dividing cells. These medications circulate throughout the body as a systemic treatment, allowing them to reach cancer cells that have spread from their original location. This widespread action is useful for treating cancers that have spread.
These drugs interfere with a cell’s ability to replicate its DNA or to divide. Some drugs, like alkylating agents, directly damage DNA to prevent cell reproduction. Other types, such as antimetabolites, mimic the building blocks of DNA and RNA. When cancer cells incorporate these fake substances, their metabolic pathways are disrupted, halting further growth.
Chemotherapy drugs target all rapidly dividing cells, not distinguishing between cancerous and healthy ones. This lack of discrimination causes the common side effects associated with the treatment. This affects healthy cells in hair follicles, the digestive tract, and bone marrow, leading to side effects like hair loss, nausea, and low blood cell counts.
However, unlike cancer cells, healthy cells have robust repair mechanisms that allow them to recover after the treatment cycle is complete. This is why side effects often subside after treatment ends. The treatment is given in cycles, with periods of rest in between to allow the body’s healthy cells time to recover from the drug’s effects. It can be administered through several methods:
- Intravenous (IV) infusion directly into a vein
- Orally in the form of pills
- Injection into a muscle
- Delivery to a specific area of the body
Targeted Therapy
Targeted therapy is a more precise approach to cancer treatment than chemotherapy. These drugs interfere with specific molecules involved in the growth and survival of cancer cells. This approach leverages the unique genetic mutations found in cancer cells, which create specific targets for treatment.
The drug is a “key” designed for a specific molecular “lock” on or in a cancer cell. When the drug binds to this target, it blocks the cancer’s growth or causes the cell to die. This precision means healthy cells are largely unaffected, leading to fewer severe side effects than chemotherapy.
Some targeted therapies block signals that tell cancer cells to grow and divide. Others may stop the development of new blood vessels that tumors need to grow, a process known as angiogenesis. Certain targeted drugs can also deliver toxic substances directly to cancer cells, sparing normal cells from harm.
For a patient to receive targeted therapy, their tumor must be tested for the specific molecular targets. This testing ensures the drug will be effective against the unique characteristics of their cancer.
Small-molecule drugs are a common type of targeted therapy that are small enough to enter cancer cells and block targets inside them. Another major class is monoclonal antibodies, which are lab-created proteins designed to attach to specific targets on the outside of cancer cells. Once attached, they can mark the cancer cell for destruction by the immune system or block it from receiving growth signals.
Immunotherapy
Immunotherapy enhances a patient’s immune system to recognize and destroy cancer cells. The immune system can identify and eliminate abnormal cells, but cancer cells can evade this process. Immunotherapies help restore the immune system’s ability to fight the disease.
Checkpoint inhibitors are a common form of immunotherapy. The immune system has “checkpoints” that regulate its response, and some cancer cells use these to put the “brakes” on the immune system. Checkpoint inhibitors are drugs that block these connections, releasing the brakes and allowing immune cells to attack the cancer.
CAR T-cell therapy is another advanced immunotherapy. This treatment involves removing a patient’s T-cells, a type of immune cell, and genetically engineering them in a laboratory to produce specific receptors called chimeric antigen receptors (CARs). These newly equipped T-cells are then infused back into the patient. The receptors help them identify and attach to a specific protein on the surface of cancer cells, leading to their destruction.
Cancer vaccines are another type of immunotherapy designed to treat existing cancer. They work by introducing cancer-specific antigens into the body. This helps the immune system recognize and attack cancer cells that have those antigens.
The effectiveness of immunotherapy can vary among individuals and cancer types, and not all patients respond to these treatments. Researchers are working to understand why some cancers are more responsive and to identify biomarkers that predict which patients will benefit.
Hormone Therapy
Hormone therapy is used for cancers sensitive to hormones, such as certain types of breast and prostate cancer. This therapy works by cutting off the supply of these hormones or by preventing cancer cells from using them.
One approach stops the body from producing the hormones that fuel the cancer. This is done with medication or by surgically removing hormone-producing glands like the ovaries or testicles. Another approach blocks hormone receptors on cancer cells, which prevents the natural hormone from signaling the cell to grow and divide.
In estrogen receptor-positive (ER-positive) breast cancer, drugs called selective estrogen receptor modulators (SERMs) bind to estrogen receptors, preventing estrogen from fueling growth. In prostate cancer, drugs known as anti-androgens can block testosterone from binding to receptors on prostate cancer cells. This slows the cancer’s progression.
Hormone therapy is often used with other treatments like surgery or radiation to reduce the risk of cancer returning. The specific type of hormone therapy used depends on the type of cancer, its hormone receptor status, and the patient’s overall health.
How Treatment Plans Are Developed
Developing a cancer treatment plan involves a team of medical specialists. This team may include a medical, surgical, and radiation oncologist who collaborate on a strategy. The plan is tailored to the individual patient based on several factors.
The primary factors considered include:
- The specific type of cancer and its stage, which describes its size and spread.
- Biomarker testing results, which identify genetic mutations or proteins in the tumor. This helps determine if a patient is a good candidate for certain targeted therapies or immunotherapies.
- The patient’s overall health, age, and any other existing medical conditions. These factors influence which treatments a patient can tolerate and the potential for side effects.
- The patient’s personal preferences and quality of life goals, which ensure the plan aligns with their values.
A combination of treatments is often used to achieve the best outcome. For instance, a patient might receive chemotherapy to shrink a tumor before surgery, followed by radiation. This use of multiple treatment types is known as combination therapy and is a common strategy in modern cancer care.