Chemotherapy Protocols and The Cell CycleCancerous tumors display properties of uncontrolled cell division, in contrast to normal cells. When “normal” cells come in contact with like cells, they stop dividing, a mechanism referred to as contact inhibition. Malignant cells do not have this absility. Images of cancer cells confirm that cancerous cells are unable to stop dividing when they come into contact with similar cells. Cancer cells do not have in place the normal checks and balances, as is required for regulating cell division. The cell division process depends on the cell cycle, regardless of whether they are normal or cancerous cells. Cell cycles start with the resting stage, go through the active growing stages, and eventually reach mitosis (division). The effectiveness of chemotherapy in destroying cancer cells is determined by its ability to stop cell division. In general, chemotherapy drugs seek to damage the RNA or DNA that carry the basic information on the cell division mechanism. The cancer cells die when they are unable to divide. The faster the rate of cell division in cancer cells, the more is the probability that chemotherapy will kill those cells, resulting in shrinkage of the tumor. They also trigger cell suicide (self-death or apoptosis). Chemotherapy drugs that eliminate cancer cells only during their division process are known as cell-cycle specific. Drugs that destroy cancer cells in their resting phase are known as cell-cycle non-specific. The schedule for chemotherapy is fixed based on the type of cell, their division rate, and the time when a specific drug will be most effective. This is the main reason as to why chemotherapy is usually administered in cycles. Chemotherapy works most efficiently at destroying cancer cells that are dividing rapidly. However, it cannot differentiate between cancerous and normal cells. Eventually, the “normal” cells will grow back to normal, but side effects occur in the meantime. Normal cells that are affected the most by chemotherapy include the blood cells, and the cells lining the mouth, the bowel and stomach and the hair follicles. Associated side-effects include low blood count, nausea, diarrhea, mouth sores, and/or hair loss. Different parts of the body may get affected by different drugs. Anti-neoplastic chemotherapy drugs have been categorized into five different classes based on the mechanism they employ for eliminating cancer. However, these drugs share some common properties even when they are divided into groups. Typically, cells grow, live and die in a predictable manner. Cancer is said to have developed when specific cells start dividing and multiplying in an uncontrolled manner, having lost the ability to halt this process. Chemotherapy protocols seek to kill cancer cells by preventing the cells from dividing and multiplying. However, some healthy cells, especially those that are naturally programmed to divide quickly, can also get affected during the chemotherapy. Chemotherapy protocols seek to inflict maximum damage to cancer cells
while minimizing the impact on healthy cells. Significant progress
has been achieved in developing effective chemotherapy protocols,
including proper identification of various forms of cancer and the
corresponding chemotherapy protocol solutions. However, there is still
plenty of work that needs to be done.
This website is sponsored by Brad Cooper* of The
Cooper, Hart, Leggiero, & Whitehead, PLLC. Cooper, Hart, Leggiero, & Whitehead is located in The Woodlands, Texas
(Greater Houston Area) and can be reached toll free at 1-800-998-9729
for more information on mesothelioma. Brad Cooper is not a medical
doctor. The information on these pages is for the education of mesothelioma
patients and their families regarding potential medical and legal
options. Patients are advised to consult with a medical doctor.
|
The
use of chemotherapy in patients with advanced malignant pleural mesothelioma:
a clinical practice guideline.
|