Mesothelioma Chemotherapy

Mesothelioma chemotherapy involves the treatment of cancer of mesothelium by delivering chemical agents and drugs that kill the malignant cells and structures in the body and arrest the production of cancerous cells. As the disease is, commonly, diagnosed in patients in it’s later stages, they are not eligible for curative surgery. Thus, chemotherapy is the widely practiced therapeutic modality in the treatment of mesothelioma.

The chemical agents used in mesothelioma chemotherapy differ from each other in their mechanism of action and in the phases of cell division where they act to arrest the metastasis of the cancerous cells.

1. Chemical agents may act by inhibiting cell division among uncontrollably dividing cells by creating unstable cross-links in the cell’s DNA or by binding with an enzyme essential for cell division.
2. There are other chemical agents that facilitate the process of apoptosis, by which malfunctioning and malformed cells are destroyed and removed from the body , so that these cancerous cells may not divide and generate similar cells.
3. The third mechanism of action of the drugs involves targeting tumor-specific antigens in a cell or specific molecular abnormalities that are known to lead to cancer. The action of these agents is described as monoclonal antibody therapy and they are categorized as chemotherapeutic agents.

The combination therapy of Pemetrexed and Cisplatin , along with folic acid and Vitamin B12 is the standard for mesothelioma chemotherapy. Combination therapy is preferred over single agent therapy because patients often become resistant to the chemical agent and may demonstrate intolerable side effects when subjected to multiple cycles of a single agent whereas, the body doesn’t develop resistance to one agent when mesothelioma patients are exposed to combination therapy.

When used as a single agent for treatment of mesothelioma patients, Cisplatin displayed limited effectiveness and showed severe side effects, but the combination therapy of Pemetrexed & Cisplatin ,popularly known as Alimta therapy, significantly increased the median survival time and symptoms control. Vitamin B12 and Folic acid are administered to alleviate the toxicity and side effects of the chemical agents used in mesothelioma chemotherapy.

Pemetrexed Chemotherapy : Pemetrexed is an Antifoliate and inhibits the action of Folic acid in cell division by arresting the synthesis of DNA and RNA by interfering in production of specific enzymes responsible for their synthesis. This hampers the process of cell division and cell replication. Thus, Pemetrexed inhibits or slows down the growth of  malignant mesothelioma cells.
Cisplatin Chemotherapy :  Cisplatin is a Platinum agent that inhibits the process of cell replication by forming unstable cross-links in the DNA structure of the cancerous cell. Cisplatin was primarily used for single agent therapy, but after it’s efficacy as a combined therapy drug became known, it’s administered with Pemetrexed to mesothelioma patients.

A mesothelioma patient undergoes a 21 day chemotherapy cycle. The patient is administered the drug combination of Pemetrexed and Cisplatin respectively on the first day of the cycle. This is followed by a 20 days waiting period to allow the patient’s immune system to recover from the side effects associated with the chemotherapy. Thus, the next cycle begins on the 22nd day. The doctor decides the course for the mesothelioma chemotherapy for the patient depending on the severity of the metastasis , age of the patient and the objective of the chemotherapy.