Question

Metronomic therapy in cancer.

Hint:

Metronomic chemotherapy offers a promising alternative to traditional high-dose chemotherapy, with reduced toxicity and potential efficacy in treating resistant cancers.

Answer 1

Metronomic therapy refers to the administration of low-dose chemotherapy on a frequent, continuous basis with the goal of minimizing side effects while inhibiting tumor angiogenesis and growth. Unlike traditional chemotherapy, which uses higher doses in cycles, metronomic therapy focuses on providing a steady, low-dose treatment to reduce tumor growth and metastasis.
Step 1: Mechanism of Action:
Metronomic chemotherapy works by inhibiting angiogenesis, the process by which tumors develop blood vessels to supply nutrients. The low doses of chemotherapy drugs used in metronomic therapy target endothelial cells that form the blood vessels, making them less capable of supporting the tumor. In addition, it modulates the immune system and induces cell death in tumor cells, especially those that are resistant to conventional high-dose chemotherapy.
Step 2: Common Drugs Used in Metronomic Therapy:
1. Cyclophosphamide: One of the most commonly used drugs in metronomic therapy, often combined with other agents. It acts by interfering with DNA replication in rapidly dividing cells.
2. Methotrexate: Methotrexate, a folate antagonist, is used in low doses for its anti-angiogenic effects.
3. Capecitabine: A prodrug of 5-fluorouracil (5-FU), which is used in combination with other agents to treat various cancers, particularly breast cancer.
4. Vinblastine: Another chemotherapy agent used in metronomic regimens for its ability to inhibit angiogenesis and tumor cell proliferation.
Step 3: Advantages of Metronomic Therapy:
1. Reduced Toxicity: Since the drug doses are much lower than traditional chemotherapy, patients experience fewer side effects, improving quality of life.
2. Chronic Treatment: Metronomic therapy can be used continuously, allowing for long-term management of cancer.
3. Improved Response in Resistant Cancers: Metronomic therapy has shown promise in cancers that are resistant to conventional chemotherapy, such as metastatic breast cancer and gliomas.
Step 4: Clinical Application:
Metronomic therapy is used in both solid tumors and hematological cancers. It is often used in combination with other therapies, such as immunotherapy, targeted therapy, or radiotherapy, to enhance its effectiveness. Clinical trials continue to explore its potential in various cancer types.