Efficacy and tolerability of tropisetron in the prevention of cisplatin-induced nausea and vomiting in advanced non-small cell lung cancer

Employment of substandard antiemetic prophylaxis in recent trials of chemotherapy-induced nausea and vomiting

OBJECTIVE

To determine the prevalence of substandard antiemetic therapy among recently published trials conducted in patients with cancer who received emetogenic chemotherapy.

DATA SOURCES

A MEDLINE search was conducted (2000-July 2004) using the key words 5-HT(3) antagonists, ondansetron, granisetron, dolasetron, tropisetron, ramosetron, palonosetron, NK-1 antagonists, and aprepitant.

STUDY SELECTION AND DATA EXTRACTION

All antiemetic trials in patients receiving chemotherapy that were published from January 2000 to July 2004 were evaluated. Standard prophylactic antiemetic therapy was derived from contemporary antiemetic guidelines published by oncology professional organizations and expert panels. The number of patients and studies in which patients received standard and substandard antiemetic therapy was determined for both the acute and delayed phases of chemotherapy-induced nausea and vomiting (CINV). Separate determinations were made for severely and moderately emetogenic chemotherapy. The annual percentage of studies in which substandard antiemetic prophylaxis was given and the percentage of patients who received substandard prophylaxis also were determined.

DATA SYNTHESIS

Fifty-six studies were reviewed, which included a total of 10 274 patients and 125 study arms. The percentage of patients who received substandard antiemetic prophylaxis was 30% (n = 3063) for acute CINV and 33% (n = 3413) for delayed CINV. The average annual percentage of studies that employed substandard prophylaxis during this time period was 54%.

CONCLUSIONS

In recent antiemetic trials for CINV, the employment of substandard antiemetic therapy is common. These results raise important ethical questions regarding contemporary antiemetic trial design.

5-HT(3)-receptor antagonists in the management of nausea and vomiting in cancer and cancer treatment

The 5-HT(3)-receptor antagonists, considered as 'gold standard' therapy for cancer patients, are generally perceived to have similar efficacy and safety profiles, andmost antiemetic guidelines do not distinguish between agents. However, important pharmacological differences exist between agents, which may translate into potential benefits for some patients. In particular, 5-HT(3)-receptor antagonists vary in the nature of their receptor antagonism and plasma half-lives, possibly leading to differences in duration of action. Agents with a longer duration of action provide antiemetic protection throughout the acute emetic period (24 h) with a single daily dose, whereas shorter-acting agents, e.g. ondansetron, may require multiple dosing for full efficacy. Differences also exist between agents in their hepatic metabolism and cardiovascular safety, which may present particular problems for elderly patients who often receive additional medications for comorbid conditions, increasing the risk of drug-drug interaction. Recent antiemetic guidelines from the National Comprehensive Cancer Network recommend preferential use of palonosetron for moderately emetogenic chemotherapy; however, this agent is newly approved and key clinical questions remain unanswered by clinical trial data. Selection of an appropriate 5-HT(3)-receptor antagonist should be based on proven efficacy and safety, as well as on the individual characteristics of the patient.

Nausea: the neglected symptom?

Advances in antiemetic therapy over the past decade have undoubtedly eased the burden of radiotherapy- and chemotherapy-induced nausea and vomiting. Despite this, these distressing side-effects of cancer therapy are still experienced by some patients. Moreover, nausea has both a higher incidence and a greater effect on patient quality of life than vomiting. The impact of nausea may therefore warrant more attention than perhaps it has received previously, and there is undoubtedly room for improvement regarding its treatment. Recognizing and treating nausea is complicated by the fact that it can only be measured subjectively by the patient rather than objectively by clinical staff. However, various patient-centred strategies may be employed by nurses to ensure self-reporting of the occurrence and impact of nausea. Nurses may also be best placed to identify patient-related prognostic factors in order to determine the risk of nausea. Antiemetic guidelines recommend the use of a 5-HT3-receptor antagonist for the control of emesis with moderate and highly emetogenic cancer therapy. Although guidelines do not distinguish between the available agents, pharmacological differences do exist, and it is necessary to consider this when tailoring regimens to individual patients. As with any therapy, less complicated dosing regimens are likely to improve compliance, an issue that may be particularly pertinent in nauseated patients who are unable to ingest multiple doses. Furthermore, the focus of antiemetic therapy should be on prevention, as the presence and severity of acute symptoms have been linked to occurrence of symptoms in the delayed phase and the likelihood of anticipatory nausea and vomiting with further treatment cycles. This review aims to assess the potentially neglected symptom of nausea and focuses on recognizing and controlling this side-effect of cancer therapy.

Antiemetic therapy in patients receiving cancer chemotherapy

PURPOSE/OBJECTIVES

To examine the currently available antiemetic medications and review their uses in the treatment of chemotherapy-induced nausea and vomiting (NV).

DATA SOURCES

Published articles and book chapters.

DATA SYNTHESIS

NV is a common yet potentially serious side effect of chemotherapy. Nurses must understand the physiology of NV, its impact on patients, and the proper use of antiemetic medications to effectively manage this problem. Antiemetic medications vary in mechanism of action, indications for use, and adverse effects.

CONCLUSIONS

Nurses are in a position to identify patients who are at risk for NV and to manage their care using accepted practice guidelines.

IMPLICATIONS FOR NURSING

Although practice guidelines have been established, the nurse's role in assessment and implementation of care is critical in the prevention and management of chemotherapy-induced NV.