Nausea and vomiting (N&V) are common symptoms in patients with advanced cancer, occurring in approximately 21% to 68% of these patients.[1,2] The underlying pathophysiology and treatment differs somewhat from nausea related to radiation treatment or chemotherapy. Chronic nausea can significantly impair a patient's quality of life.
This complementary and alternative medicine (CAM) information summary provides an overview of the use of laetrile as a treatment for people with cancer. The summary includes a history of laetrile research, a review of laboratory studies, the results of clinical trials, and possible side effects of laetrile use.
This summary contains the following key information:
Laetrile is another name for the chemical amygdalin, which is found in the pits of many fruits and in numerous plants.
Chronic nausea in the advanced cancer setting is often multifactorial in origin.[1,2,3] Medications, including some that are frequently prescribed in this setting-such as opioids, nonsteroidal anti-inflammatory drugs, and selective serotonin reuptake inhibitor antidepressants-may be responsible.
In the case of opioids, nausea frequently resolves spontaneously a few days after initiation of treatment. In some cases, however, it may persist. Nausea resulting from the accumulation of active opioid metabolites (morphine-6-glucuronide) has been described, and patients with impaired renal function may be at increased risk. Opioids invariably produce constipation if prophylactic measures are not taken (namely, the use of a regular laxative regimen), and constipation is one of the most common causes of nausea in patients with advanced cancer.[5,6,7,8]
Opioid-induced gastrointestinal (GI) motility problems may compound the problem of diminished GI motility that many patients experience as part of the anorexia-cachexia syndrome of advanced cancer. The autonomic dysfunction that often accompanies this syndrome results in decreased GI motility, early satiety, and chronic nausea.[9,10,11] Other causes of chronic nausea in these patients include the following:
Nausea, like many other symptoms, may have psychological undercurrents that either exacerbate or induce chronic nausea.
A comprehensive history that includes determining the frequency and effectiveness of bowel movements and laxative therapy is essential. Concurrent medications are reviewed, and the frequency and nature of N&V is documented. Examination will assess for bowel obstruction, fecal impaction, dehydration, and raised intracranial pressure. History and physical examination are poor at determining the extent of constipation. A plain flat-plate x-ray of the abdomen can be very useful to this end. Surgical x-ray views of the abdomen may be helpful if a bowel obstruction is suspected. Investigations to determine blood levels of electrolytes, calcium, and renal parameters may also be helpful.