Chronic nausea is a common, unpleasant symptom in patients with advanced cancer. The distress associated with nausea has enormous impact on the quality of life of this group of patients. More than half of cancer patients report nausea as one of the most distressing symptoms they encounter during the trajectory of their illness. Nausea is particularly prevalent in patients under age 65, females, patients receiving opioid analgesics, and patients with stomach, breast, or gynecologic cancer.

There is no consensus on the definition of chronic nausea, but for the purpose of research it is defined as nausea lasting longer than 4 weeks.

Etiology

Causes of nausea in cancer patients are often multifactorial – they may be related to the cancer itself or the treatment for the cancer. Figure 64.1 summarizes common causes of nausea in cancer patients.

Gastrointestinal causes are common. Amongst the gastrointestinal causes of nausea, constipation is probably the most prevalent etiology. Advanced cancer patients are frequently taking opioid analgesics that cause delayed gastric emptying and slower intestinal transit time. In addition, decreased mobility, poor hydration, and co-exposure to other medications that contribute to constipation are often seen in this population (see Chapter 49).

Nausea and constipation may also be manifestations of chronic malignant bowel obstruction (see Chapter 59). Such obstruction can result from locally advanced disease such as gynecologic and gastrointestinal malignancies or adhesions in patients with prior abdominal surgeries or previous abdominal radiation.