Chemotherapy-induced nausea and vomiting (CINV) is one of the most common and most feared adverse events that can be experienced by cancer patients [1–4]. CINV is associated with significant morbidity which has a negative effect on patient quality of life. Its occurrence essentially depends on the dose and type of chemotherapy agent used in treatment [5, 6].
There are currently many anti-emetic agents that may be used as prophylaxis and treatment for CINV, including 5-hydroxytryptamine 3 (5-HT3) receptor antagonists, corticosteroids, neurokinin 1 (NK-1) receptor antagonists, dopaminergic receptor antagonists, benzodiazepines, neuroleptics and cannabinoids [7]. However, despite the fact that antiemetic treatments have been improving over the years with the introduction of new drugs, there are still patients who are not protected against CINV [8, 9]. Nausea and delayed CINV (occurring >24 h post-chemotherapy) are reported as particular challenges in clinical practice [10–13].
Most studies that assess the incidence of chemotherapy-induced nausea and vomiting have been conducted in groups of patients who received highly emetogenic chemotherapy (HEC). There are very few studies conducted with moderately emetogenic chemotherapy (MEC), and these are mainly limited to anthracycline-cyclophosphamide (AC) treatments [13] which, nowadays, the majority of therapeutic guides consider to be HEC [5, 6]. For this reason, there is very little data related to the incidence of CINV in treatment-naive patients who receive MEC and collected systematically as for example by using a patient diary [14]. However, in studies that include nausea and vomiting as an objective, it is recommended that the information provided by the patients themselves is used, as this will allow for a greater ability to compare the regimens and data from various trials [4, 15]. Despite being able to accurately predict the prevalence of acute CINV, health professionals often underestimate the frequency of delayed nausea and vomiting, so closer monitoring is required by them throughout the complete treatment period [16].
There are hardly any studies in the medical literature with MEC regimen containing carboplatin and other regimens used in the treatment of colorectal cancer. The objective of this study was to determine the incidence of nausea and vomiting when appropriate antiemetic therapy is administered within various MEC regimens, ensuring that these regimens (carboplatin and oxaliplatin and/or irinotecan) were represented in the total sample, as well as to evaluate the perception Spanish physicians have regarding the incidence of CINV in these MEC regimens.
Patients and methods
Design
A prospective, observational multi-centre study conducted in 19 hospitals in Spain, between April 2012 and May 2013, in patients diagnosed with cancer who were chemotherapy-naive and who were scheduled to receive moderately emetogenic chemotherapy treatment (MEC). In order to be included in the study, patients had to have signed the informed consent form, be adults (≥18 years old) and be indicated for treatment with oxaliplatin and/or irinotecan in the case of colorectal cancer and with carboplatin or MEC regimens (no AC) in the case of any other type of cancer. Patients, who were unable to take oral medication, presented vomiting in the 24 h preceding the first chemotherapy cycle were under treatment with radiotherapy or presented with brain metastases were excluded from the study.
The allocation of a patient to a specific therapeutic strategy was not previously decided by the protocol but rather was determined by usual medical practice, and the decision to prescribe chemotherapy treatment was prior to patient inclusion.
The study was approved by the ethics committees at each of the participating sites and was conducted in accordance with Good Clinical Practice (GCP) guidelines and the Declaration of Helsinki. All of the patients signed the informed consent.
Data collection and assessments
Investigators were instructed regarding the data to be recorded during the study. Before administering the MEC to patients, they had to answer three questions regarding their perception of the incidence of nausea and vomiting following chemotherapy administration, the use of rescue medication and their perception of the efficacy of the antiemetic measures prescribed.
Patients’ demographic data, clinical information on the cancer, metastases, chemotherapy regimen, administered prophylaxis for vomiting and/or nausea and antiemetic medication prescribed were recorded by the investigator during the course of the study. The study endpoints were complete response defined as no emesis and no use of rescue therapy for cycle 1 and complete protection defined as no emesis, no significant nausea and no use of rescue medication. Significant nausea was defined as nausea scored ≥25 mm to 100 mm visual analogue scale (VAS).
The patients who agreed to participate in the study received a diary covering the first 5 days following MEC administration. Patients were instructed on how to complete the diary, in which they had to record the following on a daily basis: vomiting and nausea episodes, the intensity of the nausea, determined through a horizontal 100 mm VAS of which the left end corresponded to “I have NO nausea today” and the right end to “the worst possible nausea”, as well as the use of antiemetic rescue medication. On the first day of the second cycle, they had to return the duly completed patient diary to the doctor.
Sample size
A maximum of approximately 285 subjects were recruited.
According to previous estimates of the percentage of patients with MEC who experience an episode of vomiting and assuming an accuracy of 10 %, 93 patients were needed to detect an incidence of vomiting of 40 %, with an overall significance of 0.05. Considering a 10 % of lost to follow up, the number of patients were 102 per group. Groups 2 and 3 included 90 patients each, and the analysis of these subgroups included also to patients in the overall MEC group meet the specific characteristics (or carboplatin-based regimens or patients diagnosed with CRC receiving oxaliplatin and/or irinotecan), a final sample of 102 patients in each group are guaranteed.
In the first phase, each site recruited seven patients treated with MEC regimens and then, other six patients subsequently were enrolled in each defined subgroup.
Statistical analysis
A descriptive analysis was performed on all of the variables (demographic variables and characteristics of the patients, the disease and the MEC treatment received) for all valid patients. Quantitative variables were described through their mean, median, standard deviation, minimum, maximum and the total number of patients with available data, and the qualitative variables were in the form of tables with relative and absolute frequencies. For the primary objective, the incidence of nausea and vomiting associated with MEC regimens was evaluated during the 5 days following administration, within the first 24 h following administration of the first chemotherapy cycle (acute phase) and during the four subsequent days (delayed phase), expressed using the percentage of patients with vomiting and the percentage of patients with nausea and their corresponding 95 % confidence intervals. For the secondary objectives, the percentage of patients with vomiting, nausea, significant nausea, use of rescue medication, lack of complete response and lack of complete protection were analysed for both acute and delayed phases of emesis.
The analyses performed with categorical result variables used the chi-square test or Fisher’s exact test. McNemar’s test was used for comparisons made between the two study phases (acute and delayed). The Cochran-Armitage trend test was used to evaluate a trend. The significance level used was 0.05. All of the statistical analyses were performed with SAS v.9.3 software.