The National Cancer Institute reports that 1,479,350 new cases of cancer were diagnosed in 2009, and cancer caused 562,340 deaths in the United States that year. Cancer is commonly treated by a combination of therapies that may include chemotherapy, the use of toxic drugs to kill cancer cells, or radiation therapy, using high-dose radiation. Both chemotherapy and radiation therapy have a number of adverse side effects within the body.
Decreased Blood Cell Counts
Bone marrow cells are a type of stem cell that gives rise to the cells of the blood, including platelets and red and white blood cells. The stem cells continually divide to provide a constant supply of new blood cells to meet the body's needs. Chemotherapy drugs target dividing cells, from cancer cells to bone marrow cells. Radiation therapy of some tumors can also damage the bone marrow cells, leading to blood disorders.
The decrease in blood cells can leave the patient vulnerable to infection due to low white blood cell counts, may cause anemia from low red blood cell counts, and may cause bleeding disorders due to low platelet counts. These side effects are often temporary, and will resolve themselves after cessation of treatment. In some cases, additional treatments, such as bone marrow transplants, may be required.
Nausea
A number of chemotherapeutic agents cause nausea at the onset of treatment, and over the course of chemotherapy. Similarly, patients receiving radiation therapy often experience nausea and vomiting that may occur within a few hours following radiation and may persist for the length of treatment.
Patients experiencing nausea should take care to maintain fluid levels to remain well-hydrated. Patients should try eating small meals, and avoid high-fat foods before treatment, suggests ChemoCare.com. In some cases, doctors can prescribe anti-nausea medications to alleviate the adverse reaction to radiation or chemotherapy.
Second Cancers
A possible side effect of chemotherapy or radiation therapy is the development of second cancers, reports the American Cancer Society. Radiation therapy kills cancer cells by delivering a high dose of DNA-damaging radiation, and the extent of the DNA damage causes cell death. Cells close to the tumor also receive a small dose of radiation that can lead to genetic mutations. Similarly, certain chemotherapy drugs work by inducing massive DNA damage to cells. Since some non-cancerous cells are affected by chemotherapy, genetic mutations in these cells may increase the risk of developing other forms of cancer. Although the benefits of receiving chemotherapy or radiation therapy far outweigh the risks for several cancer patients, administration of these therapies can increase the risk of developing secondary tumors in the future.
References
- National Cancer Institute: What is Cancer?
- National Cancer Institute: Bone Marrow Transplantation and Peripheral Blood Stem Cell Transplantation
- ChemoCare.com: Nausea, Vomiting & Chemotherapy
- Masonic Cancer Center: Nausea and Vomiting
- American Cancer Society: Second Cancers Caused by Cancer Treatment
