Stewart D J
Ontario Cancer Treatment and Research Foundation, Ottawa Regional Cancer Centre, Canada.
Can J Physiol Pharmacol. 1990 Feb;68(2):304-13. doi: 10.1139/y90-045.
Both radiotherapy and chemotherapy for cancer are capable of causing nausea and vomiting. With both treatment modalities, the nausea and vomiting is thought to be a second-order process rather than being due to direct stimulation of neuromechanisms that control vomiting. Both a peripheral (gastrointestinal tract) and central (chemoreceptor trigger zone) effect may be operating with both radiotherapy- and chemotherapy-induced vomiting. With radiotherapy, gastrointestinal toxicity is affected by the type of radiation, radiation dose and field size, fractionation schedule, individual patient factors, and the part of the patient that is radiated. Many different factors also influence the frequency and severity of nausea and vomiting following chemotherapy. With both radiotherapy and chemotherapy, the frequency and severity of nausea and vomiting is probably mediated by a reduction in breakdown of various neurotransmitters. It is presumed that as the levels of neurotransmitters increase, nausea and vomiting develop. Antagonists of these neurotransmitters may afford some antiemetic protection. Nausea and vomiting may be so severe in patients with cancer that they may refuse potentially curative therapy because of it. Anticipatory nausea and vomiting may develop in patients who have become quite sick after receiving treatment. Exposure to stimuli associated with the emetogenic agent is then sufficient to trigger nausea and vomiting. Standard antiemetics do not help anticipatory nausea and vomiting, although behavioural training may. A variety of different drugs have proven useful as antiemetics, including dopamine antagonists such as phenothiazines, metoclopramide, corticosteroids (dexamethasone and methylprednisolone), cannabinoids, and benzodiazapines. Antihistamines and anticholinergics are of value in some situations. New serotonin antagonists appear to be very promising and are currently undergoing clinical studies. Multiagent antiemetic regimens appear to be more effective than single agent regimens in some situations.
癌症的放射治疗和化学治疗都可能导致恶心和呕吐。对于这两种治疗方式，恶心和呕吐被认为是一个二阶过程，而非直接刺激控制呕吐的神经机制所致。放射治疗和化学治疗引起的呕吐可能同时涉及外周（胃肠道）和中枢（化学感受器触发区）效应。对于放射治疗，胃肠道毒性受辐射类型、辐射剂量、照射野大小、分割方案、个体患者因素以及患者接受辐射的部位影响。许多不同因素也会影响化学治疗后恶心和呕吐的频率及严重程度。对于放射治疗和化学治疗，恶心和呕吐的频率及严重程度可能是由各种神经递质分解减少所介导的。据推测，随着神经递质水平升高，恶心和呕吐就会出现。这些神经递质的拮抗剂可能提供一定的止吐保护作用。癌症患者的恶心和呕吐可能非常严重，以至于他们可能会因此拒绝潜在的治愈性治疗。接受治疗后病情严重的患者可能会出现预期性恶心和呕吐。随后，接触与致吐剂相关的刺激就足以引发恶心和呕吐。标准的止吐药对预期性恶心和呕吐无效，不过行为训练可能有效。多种不同药物已被证明可作为止吐药，包括多巴胺拮抗剂如吩噻嗪类、甲氧氯普胺、皮质类固醇（地塞米松和甲泼尼龙）、大麻素和苯二氮䓬类。抗组胺药和抗胆碱能药在某些情况下有价值。新型5-羟色胺拮抗剂似乎很有前景，目前正在进行临床研究。在某些情况下，联合用药的止吐方案似乎比单一用药方案更有效。
