Nausea and vomiting in radiotherapy

Cancer-related deaths come second after deaths from cardiovascular system diseases. It even takes first place from time to time. The main modalities in treatment approaches are radiotherapy (RT), chemotherapy and surgery. While RT and surgery are aimed at providing local and regional control, chemotherapy is systemically effective. Localized disease is present at the time of diagnosis in more than half of the cases. 50% of cases with localized disease can be treated with RT alone. RT is used for palliative purposes in patients who cannot be treated. Therefore, RT is an indispensable part of cancer treatment. However, one of the side effects of RT is nausea and vomiting. Whether curative or palliative treatments are applied, the most important goal should be not to impair the quality of life. For this reason, the causes and treatment of nausea and vomiting associated with RT will be reviewed in this article.


Nausea and vomiting after irradiation is a complex, multifactorial clinical event. Radiation-related causes that induce nausea and vomiting are shown in table 1. The higher the “linear energy transfer” (LET) of the radiation used, the greater the potential for nausea. The higher the dose administered during each fraction increases the risk of nausea proportionally. Nausea occurs in 30-50% of cases within 3 weeks when conventional fractional dose RT is applied to the upper abdomen once. Nausea manifests more rapidly and severely in those who receive a higher single dose of RT (5 Gy< ). It is also known that the threshold value for cumulative dose accumulation for nausea is 3 Gy. As the radiotherapy field expands, the incidence of nausea and vomiting increases. The most nausea and vomiting is observed in whole body irradiation. Researcher Coccia reported mild to moderate vomiting rate as 95% after 12 Gy whole body irradiation. Severe vomiting was observed in 5% of the cases. Another important factor is the irradiated area. Abdomen and pelvic area (abdomen) are the most sensitive areas. In Figure 1, the potential for nausea according to the irradiated areas is shown. In the moments following exposure to radiation in the small intestines, substances that trigger nausea begin to be released. In addition, the “chemoreceptor tigger zone” in the brain increases nausea by being triggered by vagal (stomach nerve) stimuli from the upper gastrointestinal tract. Cubbeddu also showed that serotonin plays a role as a mediator in radiation-induced nausea. Chemotherapeutic agents used before or simultaneously with radiotherapy are other factors that increase nausea. The characteristics of the individual being treated also have an important place. Being in the young adult group, being a premenopausal woman, being overweight, conditioned to nausea due to recurrent vomiting, being anxious, presence of motion sickness, uncontrolled pain during treatment are factors that increase nausea and vomiting.


First of all, nausea and vomiting should be tried to be prevented by minimizing the causes. For example, three-dimensional planning systems, the use of multileaf collimators can be effective by narrowing the irradiated field. Conventional fraction doses can be chosen instead of high fraction doses. In addition, since the nausea potential of the gastrointestinal system is greater in the morning hours of the day, the patient can be treated in the afternoon. Antiemetic drugs can be used prophylactically before treatment (5). If nausea and vomiting occur despite these, the use of antiemetic drugs should be started. The most commonly used drugs are neuroleptics, antiemetics, anticholinergics, steroids, benzodiazepines, cannibinoids, benzamides and 5-HT 3 receptor antagonists. The most commonly used and doses of these drugs are summarized in Table 2.


The introduction of 5-HT 3 receptor antagonists has achieved significant success in controlling nausea and vomiting. However, full success has not been achieved especially in whole body irradiation. Therefore, new studies are needed to develop more effective strategies for controlling early and delayed nausea.

Table 1. Factors affecting radiation-induced nausea and vomiting

Single and total dose


Irradiated field width

organs in the RT field

RT technique and energy of the beam

Prior or concomitant treatment

Individual factors






1-3 mg/kg iv, po, every 2-4 hours

100mg; iv, im, po, every 4-8 hours





25mg. iv, im., every 4-6 hours

10-20mg. iv, po, every 4-6 hours

1-3 mg IV, IM, every 2-6 hours




1-2 mg/m2 iv every 4 hours

5-10 mg iv, im, po, every 4 hours



1.5 mg sc every 12-72 hours




150 mg po every 4-8 hours

50 mg iv, im, po, every 6-12 hours




4-20 mg iv, po, every 4-24 hours

200-500 mg iv every 4-24 hours




1 mg every 12 hours

0.5 mg every 24 hours

5-HT3 antagonists




32 mg iv every 24 hours/8 mg. every 8-12 hours

3-9 mg iv, po every 8-24 hours

5-10 mg iv, po, every 24 hours

Table 2. Drugs used in the treatment of nausea and vomiting and their doses

po: peroral

iv: intravenous

im: intramuscular

sc: subcutaneous


Figure 1: Nausea potential percentages of radiation by irradiated area

A) Whole body irradiation B) Half body irradiation C) Partial body irradiation

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