Home > Cancer Treatment Nausea

Research evidence indicates there are two major factors that trigger and prolong the nausea and vomiting following cancer treatment by chemotherapy or radiation therapy: (1) Irritation or injury to certain cells within the stomach and Digestive Tract of the body; and (2) Neurotransmitters (Serotonin, Histamine) released from the stomach that signal the brain when a toxic substance is in the body.

The Anatomy

The Physiology

Cancer cells are rapidly dividing, rapidly multiplying malignant cells that quickly spread within the body. Chemotherapy treats cancer by introducing drugs into your system that will destroy rapidly dividing cells, thereby stopping the cancer from growing. However, your body also has other rapidly dividing, healthy cells that get injured or destroyed at the same time, including the cells in the inner-stomach.

Nausea and vomiting from cancer treatment is the result of neurological “signaling” back and forth between the stomach (GI Tract) and the Brain. In the brain, the Chemoreceptor Trigger Zone, located in the Medulla (lower brainstem), is responsible for monitoring cerebrospinal fluid (CSF) for signs of toxins, chemicals, and other stimulants that might be harmful to the body. As a mechanism for protecting the body from harm, the Chemoreceptor Trigger Zone can send signals to the Vomiting Center of the brain (also located in the Medulla). This serves to empty the contents of the stomach in case that’s a source of contamination.

The stomach can also react to poisons, injury, bacteria or viruses by signaling the Chemoreceptor Trigger Zone itself. This is accomplished by “neurotransmitters”, biochemical messengers which act by stimulating or inhibiting specific nerve impulse transmissions. Both Chemotherapy and Radiation therapy can cause the release of two neurotransmitters - Serotonin and Histamine – which in turn can signal the CTZ and help activate the brain’s Vomiting Center.

In Chemotherapy, many of the drugs used for treatment will damage the rapidly-dividing stomach cells along with the rapidly-dividing cancer cells. This internal injury causes stomach cells to release Serotonin into the Peripheral Nervous System, and Serotonin ends up in the Cerebrospinal Fluid (CSF). Other Chemotherapies cause the release of Histamine, which signals an allergic reaction/immune response to the brain, and the possible presence of toxins or allergens within the body.

Radiation Therapy can also cause the release of Histamine into the Peripheral Nervous System. And radiation to any part of the stomach or small intestines can damage GI Tract cells causing the release of Serotonin. In addition, radiation to the brain itself can directly affect the CTZ and the Vomiting Center.

When the Chemoreceptor Trigger Zone detects increasing levels of Serotonin or Histamine in the Cerebrospinal Fluid, it signals this information to the Vomiting Center. If the signals persist, the Vomiting Center will send sickness-inducing signals through the Vagus Nerve to the stomach. – The result is the nausea and vomiting that often accompanies Cancer Treatment by Chemotherapy or Radiation Therapy.