Chemotherapy-Induced Nausea and Vomiting

In 2018 alone, there is estimated to be 138,321 new cases of cancer and 48,586 deaths due to cancer. One of the main treatments used is chemotherapy, with nausea and vomiting tending to be common side effects experienced by patients. Depending on the extent of chemotherapy-induced nausea and vomiting (CINV), it can affect a person’s lifestyle, quality of life, and perception and compliance to further cancer treatments. In extreme scenarios, it can cause metabolic imbalances, nutrient depletion, anorexia, degeneration of patient’s performance and mental status, oesophageal damage, wound ruptures, and complete withdrawal from possibly beneficial anticancer treatment.

CINV can vary based on the onset, severity, and duration, which is influenced by the specific chemotherapy agent or combination of agents used, dosage, route, and schedule of administration. The following factors also increase a patient’s risk of having CINV:

• Young women (<50 years of age);
• Prior chemotherapy;
• History of motion sickness and/or nausea in pregnancy;
• Poor health status;
• Experienced CINV with earlier treatments; and
• No alcohol consumption.

There are several types of nausea and vomiting related to chemotherapy which can be classified as shown in Table 1.

Table 1. Classification of chemotherapy-induced nausea and vomiting

Patients undergoing chemotherapy should be monitored for signs of dehydration such as postural hypotension, tachycardia, low urine output, and headaches. Patients can also present with other symptoms like paleness, diaphoresis/increased sweating, salivation, and in extreme cases, anorexia. Because nausea and vomiting are non-specific symptoms, it is important to distinguish and exclude chemotherapy from other potential triggers such as:

• Constipation;
• Bowel obstruction;
• Gastroparesis;
• Malignant ascites;
• Anxiety;
• Fluid and electrolyte imbalances (e.g. hypercalcaemia and renal failure);
• Uraemia;
• Metastases or tumour site involving the gastrointestinal tract, liver, or central nervous system;
• Raised intracranial pressure;
• Peptic ulcer disease;
• Recent or concurrent radiation therapy; and
• Vestibular dysfunction.

The severity of CINV experienced can be classified into grades as shown in Table 2.

Table 2. Chemotherapy-induced nausea and vomiting grades

In non-urgent situations where immediate medical intervention is not required, healthcare professionals can provide support and patient education. Lifestyle recommendations which can be discussed are:

• Frequent small meals (5 to 6 times daily) and chew food well. Do not lie down immediately after eating;
• Eat food cold or warm (not hot);
• Increase fluid intake to 8 – 10 cups daily (2 to 2.5 litres a day) via soups, popsicles, and small sips (caution if the patient is on a fluid restriction);
• Have assistance in preparing meals;
• Avoid alcohol or tobacco;
• Avoid foods or fluids that are spicy, fatty or have a strong taste or smell;
• Limit caffeine intake; and
• Peppermint tea and food with ginger may be of benefit.

Patients with dyspepsia may benefit from an antacid like a proton-pump inhibitor or H₂-receptor antagonist.

A chemotherapy agent can be differentiated based on its likelihood to cause emesis as shown in Table 3.

Table 3. Emesis risk of chemotherapy agents

Generally, the ultimate goal is to have zero occurrences of nausea or vomiting. A regimen is chosen based on the emetic risk of chemotherapy, patient’s experience with antiemetics, and patient-specific risk factors. Over 90% of patients having highly emetogenic chemotherapy will experience episodes of vomiting. However, this figure is reduced to approximately 30% when patients receive prophylactic antiemetic agents. Although vomiting may often be prevented or decreased using prophylactic regimens, nausea is more challenging to control. Antiemetic therapy should be started before chemotherapy for maximum protection against CINV, and ideally, should be continued for the duration of the emetic activity of the chemotherapy agent. A patient needs to be covered for at least three days after the last dose of highly emetogenic chemotherapy has been administered, whilst moderate risk treatments often require two days of coverage.

It is recommended that all oral anti-nausea medication is administered an hour before treatment whereas intravenous doses are to be given 30 minutes prior to chemotherapy. Table 4 provides some general anti-nausea recommendations.

Table 4. General antiemetic regimens

In conclusion, it is easier to prevent nausea and vomiting than it is to treat it. Prevention is important, and optimal antiemetic therapy should be used during each cycle where round the clock anti-nausea treatment is preferred rather than on a when required basis. Patients also need to be adequately hydrated and be observed for signs of dehydration.