Adelaide, Australia—Nausea is part of a symptom cluster associated with chemotherapy, but the experience of nausea may be a symptom cluster in and of itself, according to a study presented by Ian Olver, MD, President of the Multinational Association of Supportive Care in Cancer (MASCC), Director of the Sansom Institute for Health Research, and Professor of Translational Cancer Research, University of South Australia, Adelaide, at the 2016 MASCC/International Society of Oral Oncology Annual Meeting on Supportive Care in Cancer.
When treating chemotherapy-induced nausea and vomiting, he said patients often describe nausea as a variety of symptoms. “So if you don’t treat nausea as a symptom cluster, the patient won’t tell you the nausea has gone away. This might explain why antiemetics are only having a limited effect,” said Dr Olver.
Alex Molasiotis, RN, PhD, Professor and Head of the School of Nursing, Hong Kong Polytechnic University, agreed, stating that “nausea may be broader than we think. We often connect it with vomiting, but perhaps there are other issues to consider.”
Triple antiemetic therapy has been successful in controlling vomiting in as many as 90% of patients, Dr Olver reported. But studies suggest as many as 75% of patients undergoing chemotherapy will report nausea at some stage, and others endure anticipatory or conditioned nausea years after active treatment.
Patient Perception of Nausea
Using semistructured interviews, Dr Olver and co-investigators conducted a study on 2 groups of patients with cancer who currently have chemotherapy-induced nausea (n = 21) or those who had chemotherapy-induced nausea (n = 21) to evaluate patients’ perceptions of nausea (Olver IN, et al. Support Care Cancer. 2014;22:2749-2756).
According to Dr Olver, the nature, number, location, duration, and intensity of experiences described as nausea varied across both groups. No single symptom was common to all descriptions, reinforcing the investigators’ hypothesis that nausea was indeed a symptom cluster.
Physical and psychological symptoms described by the patients in the study included dry heaving, vomiting, loss of appetite, indigestion, change of taste, dizziness, bloating, reflux, inability to concentrate, fatigue, and physical restlessness.
“All of these symptoms were part of what the patients recognized as nausea, and therefore part of what we have to treat in order to completely alleviate it,” Dr Olver said. Patients’ recognition of the site of their nausea also varied, from the upper and lower stomach to the head and throat, whereas some described it as a whole-body experience.
The onset of nausea ranged from immediate to day 5 postchemotherapy, and lasting 1.5 hours to 6 months, whereas conditioned stimuli could trigger nausea in survivors for years after treatment.
“If we’re looking at parameters of measuring nausea, duration is very important,” said Dr Olver. “If a patient has 6 hours of nausea, even if it’s mild, that’s perhaps far more serious than intense nausea for half an hour. So we’ve got to have a tool to measure both the intensity and the duration of nausea.”
For most patients in the study, distinguishing features of chemotherapy-induced nausea (as opposed to other types of nausea, such as motion sickness) included its constant presence over time, a feeling of fatigue, and its negative impact on social and work interactions. “They were scared of feeling nauseated, so they didn’t want to wander too far from their desk or from the bathroom,” Dr Olver noted. “It restricted what they could do.” Patients also cited its significant effect on their eating patterns and appetite, and said that antiemetics reduced the intensity of their nausea, but did not completely alleviate it.
Nonpharmacologic management techniques, such as distractions and relaxation, were found to be helpful among the study population. “When they were working, watching TV, or relaxing, they didn’t report as much nausea,” he added.
Many patients felt distressed, because their nausea became a constant reminder of their cancer diagnosis. However, this was sometimes reassuring to patients, because they associated the feeling of nausea with the knowledge of being treated for their cancer.
Improving Patient Quality of Life
Dr Olver emphasized the importance of treating each of the component symptoms of nausea with drugs (eg, olanzapine, cannabinoids, antacids) or with nonpharmacologic methods (eg, diet and distractions), and noted that more studies evaluating the use of cannabinoids for nausea will emerge over the next few years.
“In the future it may be possible to discover what these symptom clusters are and treat them. We want to try to develop an electronic patient-reported outcome tool to identify and assess components of the larger nausea symptom cluster over the course of chemotherapy,” Dr Olver said.
“We haven’t focused enough on the major problem of nausea, and we need to start thinking about managing the entire cluster of symptoms, otherwise we’re not going to see good results in the near future,” Dr Molasiotis said.
“I think that nausea is the new battleground. Maybe we have to treat the anxiety or indigestion or whatever other symptom patients are calling nausea in order to drive the nausea scores to zero. And if we develop a more holistic approach to nausea than we have to vomiting, we may be more successful in that sense,” added Dr Olver.