High dose chemotherapy is the administration of very high doses of chemotherapy drugs to treat cancer. Normally, patients may undergo a cycle of lower-dose chemotherapy treatment for several weeks, as a lower dose of drugs has a lower chance of inducing severe side effects. Patients receiving high-dose chemotherapy undergo a shorter treatment cycle with a higher dose of drugs, then receive additional therapy to treat the side effects of chemo. Doctors may use a number of chemo drugs for high-dose chemotherapy, depending on the characteristics of the cancer present.
Etoposide
One drug used in high-dose chemotherapy is etoposide, which has been studied for use in patients with advanced brain cancer, according to research published in 2009 by Children's Oncology Group. Etoposide belongs to a class of drugs called topoisomerase inhibitors. Topoisomerases are proteins found within the cell that function to unwind the helical structure of DNA. Since this unwinding is required for cell division, cells exposed to etoposide cannot divide. In addition, the activity of topoisomerases allows the cell to unwind its DNA to generate proteins required for survival. Upon exposure to etoposide, the cell no longer unwinds and relaxes its DNA, leading to DNA breakages as the cell attempts to divide. These breakages and damage eventually lead to cell death, killing the tumor. Patients who receive etoposide as high-dose chemotherapy often require bone marrow stem cell transplants after treatment, since high doses of etoposide profoundly damage bone marrow.
Hydroxycarbamide
Another drug employed in high dose chemotherapy is hydroxycarbamide, which is used to treat some forms of leukemia, according to CancerHelp UK. Hydroxycarbamide, also called hydroxyurea, acts by inhibiting the function of essential proteins within the cancer cell. Specifically, hydroxycarbamide prevents the cell from making chemicals called nucleotides, which act as the building blocks of DNA. Without the ability to synthesize nucleotides, the cell cannot replicate its DNA, and therefore can no longer divide. The use of hydroxycarbamide in high-dose chemotherapy can lead to severe side effects in patients, and many leukemia patients that receive high doses of hydroxycarbamide require stem cell transplants after treatment.
Esomeprazole
Esomeprazole is a high-dose chemotherapy drug currently under investigation as a treatment for breast cancer, reports ClinicalTrials.gov. It belongs to a class of drugs called proton pump inhibitors, or PPIs. PPI drugs work to inhibit the function of protein pumps found on the surface of cancer cells. In cancer development, these pumps move chemotherapy drugs out of the cell, and high levels of protein pumps can lead to chemotherapy resistance. High-dose esomeprazole is used to increase the efficacy of other chemotherapy drugs and prevent drug resistance, allowing other chemotherapy drugs to effectively kill the cancer. Through the use of high-dose esomeprazole treatment, doctors may be able to target aggressive and resistent forms of breast cancer, allowing for greater patient survival.
References
- ClinicalTrials.gov: High-Dose Chemotherapy Plus Autologous Stem Cell Transplantation Compared With Intermediate-Dose Chemotherapy Plus Autologous Stem Cell Transplantation With or Without Isotretinoin in Treating Young Patients With Recurrent High-Grade Gliomas
- CancerHelp UK: Chronic myeloid leukaemia (CML) chemotherapy drugs and their side effects
- ClinicalTrials.gov: Docetaxel and Cisplatin Chemotherapy With or Without High Dose Proton Pump Inhibitor in Metastatic Breast Cancer
