September 2016, Vol. 5, No. 7
Treating Nausea as a Symptom Cluster
Nausea is part of a symptom cluster associated with chemotherapy, but the experience of nausea might be a symptom cluster in and of itself, according to research presented by Ian Olver, MD, at the 2016 Multinational Association of Supportive Care in Cancer (MASCC)/International Society of Oral Oncology (ISOO) Annual Meeting on Supportive Care in Cancer.1
When treating chemotherapy-induced nausea and vomiting, he said patients often describe nausea as a variety of symptoms. â€śSo if you donâ€™t treat nausea as a symptom cluster, the patient wonâ€™t tell you the nausea has gone away,â€ť said Dr Olver, President of MASCC and Director of the Sansom Institute for Health Research, as well as Professor of Translational Cancer Research and Dean of Research Strategy in the Division of Health Sciences at the University of South Australia. â€śThis might explain why antiemetics are only having a limited effect.â€ť
Alex Molassiotis, RN, PhD, Professor and Head of the School of Nursing at the Hong Kong Polytechnic University, agreed, stating that â€śnausea may be broader than we think. We often connect it with vomiting, but perhaps there are other issues to consider.â€ť
Triple antiemetic therapy has been successful in controlling vomiting in up to 90% of patients, Dr Olver reported. But studies suggest as many as 75% of patients undergoing chemotherapy will report nausea at some stage, whereas others endure anticipatory or conditioned nausea years after active treatment.
Patient Perception of Nausea
Through the use of semistructured interviews, Dr Olver and colleagues conducted a study on 2 groups of cancer patients with current (n = 21) or past (n = 21) experience of chemotherapy-induced nausea (CIN) to evaluate patientsâ€™ perceptions of nausea.2
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 investigatorsâ€™ 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. â€śAll 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,â€ť he said. Patientsâ€™ recognition of the site of their nausea also varied, from the upper and lower stomach to the head and throat, while some described it as a whole body experience.
The onset of nausea ranged from immediate to day 5 postchemotherapy, and duration ranged from 1.5 hours to 6 months, whereas conditioned stimuli (eg, the smell of the disinfectant used in their treatment center) could trigger nausea in survivors for years after treatment.
â€śIf weâ€™re looking at parameters of measuring nausea, duration is very important,â€ť said Dr Olver. â€śIf a patient has 6 hours of nausea, even if itâ€™s mild, thatâ€™s perhaps far more serious than intense nausea for half an hour. So weâ€™ve got to have a tool to measure both the intensity and the duration of nausea.â€ť
Physical and Psychological Distress
For most patients in the study, distinguishing features of CIN (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. â€śThey were scared of feeling nauseated, so they didnâ€™t want to wander too far from their desk or from the bathroom,â€ť Dr Olver noted. â€śIt restricted what they could do.â€ť 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 distraction and relaxation were found to be helpful among the study population. â€śWhen they were working, watching TV, or relaxing, they didnâ€™t report as much nausea,â€ť 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. Changes in social behavior, particularly when they were denied the social interaction of eating with friends and family, also took a toll on patients, he observed.
Improving Patient Quality of Life
Dr Olver emphasized the importance of treating each of the component symptoms of nausea with either drugs (olanzapine, cannabinoids, antacids, etc) or nonpharmacologic methods (diet, distractions, etc), and noted that more studies evaluating the use of cannabinoids for nausea will emerge over the next few years.
â€śIn the future it may be possible to discover what these symptom clusters are and treat them,â€ť he said. â€śWe 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.â€ť
According to Dr Molassiotis, â€śWe havenâ€™t focused enough on the major problem of nausea, and we need to start thinking about managing the entire cluster of symptoms, otherwise weâ€™re not going to see good results in the near future.â€ť
â€śI think that nausea is the new battleground,â€ť added Dr Olver. â€śMaybe 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.â€ť
- Olver I. Nausea as a symptom cluster. Presented at: MASCC/ISOO Annual Meeting on Supportive Care in Cancer; June 23-25, 2016; Adelaide, Australia. Abstract PS051.
- Olver IN, Eliott JA, Koczwara B. A qualitative study investigating chemotherapy-induced nausea as a symptom cluster. Support Care Cancer. 2014;22:2749-2756.
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