Chemotherapy Mesothelioma Treatment
Mesothelioma requires multimodality treatment. What that means is that because it is such an aggressive form of cancer, doctors need to use more than one type of therapy to treat it.
Chemotherapy is a form of treatment that uses drugs to stop the growth of cancer cells. Depending on the class of drugs used, it accomplishes this either by killing the cells or by stopping them from dividing.
The drugs can be administered in two ways. The first is what is called systemic chemotherapy. The drugs are either taken orally or injected into a vein or muscle so that they enter the bloodstream to destroy mesothelioma cells anywhere in the body. This is used when the cancer has spread beyond the primary tumor, or to shrink a tumor that cannot be removed surgically.
The second way is called regional chemotherapy. The drugs are administered directly into the abdominal cavity to treat peritoneal mesothelioma, or into the chest cavity to treat pleural mesothelioma. This is used because the primary tumor is “localized,” meaning it hasn’t spread. Regional chemotherapy targets the mesothelioma in the chest or abdomen directly without harming healthy cells in other parts of the body. Higher doses of chemotherapy drugs can be administered using this method than can be administered systemically.
Chemotherapy is used in conjunction with a primary therapy, which is typically surgery. The first way it is used is as a neoadjuvant therapy. That means that is administered before surgery. When a tumor is large and may be difficult to remove surgically in its current state, the doctor will administer chemotherapy to reduce its size making it easier to take out.
Adjuvant therapy is another way chemotherapy is used. Adjuvant means “secondary,” and in this case, chemotherapy is the second treatment after the primary treatment of surgical removal of the tumor. It is used to be sure that the tumor will not recur.
The third way in which chemotherapy is used is for palliation. This is not for curative reasons, but rather to relieve symptoms, such as pain, that are associated with the disease. The standard drug regimen prescribed for the treatment of either pleural mesothelioma or peritoneal mesothelioma includes pemetrexed (brand name Alimta) and cisplatin (brand name Platinol).
Pemetrexed was approved in 2004 by the Food and Drug Administration (FDA) to be used in conjunction with cisplatin for the treatment of malignant pleural mesothelioma; however, it is also used with cisplatin to treat peritoneal mesothelioma. It belongs to the drug class known as folate antagonists, meaning they interfere with metabolic processes that need folate. Premetrexed prevents the functioning of three enzymes that are required for the production of purine and pyrimidine, two nucleotides found in DNA and RNA. Without the development of purine and pyrimidine, DNA and RNA aren’t formed within the cells and the cells cannot divide and grow.
Cisplatin belongs to the class of chemotherapy drugs that are platinum-based. It works by creating a platinum complex inside of a cell which binds to DNA and severely damages it, causing DNA repair mechanisms to go into action. However, the repair mechanisms see that the cells cannot be saved, so they automatically set the death of those cells into motion.
The recommended dose of pemetrexed is 500 mg/m2 (megagrams per square meter)
administered as an intravenous (by vein) infusion over 10 minutes on the
first day of each three-week chemotherapy cycle. The recommended dose
of cisplatin at is 75 mg/m2 as an intravenous infusion over 2 hours beginning
30 minutes after the pemetrexed infusion.
Patients are given folic acid orally and vitamin B12 by injection before starting therapy, and it is continued during therapy to reduce severe toxicities. Patients are also given corticosteroids during chemotherapy to decrease risk of skin rashes.
Keep in mind that chemotherapy has side effects. Their severity depends on the individual’s toleration for the drugs and the dose used. Side effects include: fatigue, risk of infection, nausea and vomiting, loss of appetite, and diarrhea. These side effects usually disappear when treatment is completed.
However, sometimes the side effects are more dangerous, such as blood in the urine or stool; confusion; reduction in urine volume or frequency; irregular heartbeat; hearing problems; lightheadedness; loss of balance; loss of motor function; seizures; slurred speech; severe headaches; uncontrolled muscle movements; vision changes; and yellowing of the skin or eyes. These should be reported to your doctor immediately.