Background: The incidence of overall (acute and delayed) chemotherapy-induced nausea and vomiting (CINV) events among patients treated with single- and multi-day low emetogenic chemotherapy (LEC) is not well established. We studied a cohort of patients receiving LEC and antiemetic prophylaxis with palonosetron (Group 1) versus other 5-HT(3) receptor antagonists (5-HT(3)-RAs) (Group 2), to determine the overall rate of CINV and the proportion of patients experiencing delayed CINV (days 2-7 of a CT cycle) in a hospital outpatient setting.
Methods: Patients aged ≥18 years with cancer diagnosis initiating single-day and multi-day LEC for the first time between 4/1/2007 and 3/31/2009 were identified from the Premier Perspective database. CINV events (ICD-9-CM codes for nausea, vomiting, or volume depletion or CINV-related rescue medications) were assessed descriptively. A generalized linear multivariate regression model was developed, estimating the overall CINV event rate among Group 1 and 2 patients in the follow-up period (first of eight chemotherapy [CT] cycles or 6 months).
Results: In the follow-up period, out of a total of 10,137 overall CINV events (single-day and multi-day LEC), 8783 events (86.6%) were identified in single-day LEC treated patients. Within single-day LEC treated events, in the first cycle, of 3184 events, 2996 (94.1%) events were delayed. Average number of delayed events per patient remained consistent throughout the eight cycles (3.1 [1st cycle] vs. 2.9 [8th cycle]; P = 0.842]). Among 2439 patients on antiemetic prophylaxis with a 5-HT(3)-RA, 10.1% (n = 247) initiated palonosetron. Regression analysis indicated that Group 1 patients (versus Group 2) had a 15.2% reduction in CINV event rate per CT cycle; P = 0.0403. Study limitations include potential lack of generalizability, absence of data on certain confounders including alcohol consumption and prior history of motion sickness, potential underestimation of incidence of uncontrolled CINV, and inability to draw conclusions pertaining to cause and effect relationship.
Conclusion: In this retrospective analysis, delayed CINV comprised a major proportion of overall CINV among cancer diagnosed patients on single-day LEC. Additionally, palonosetron prophylaxis was associated with a significantly lower overall CINV event rate versus other 5-HT(3)-RA prophylaxis in single- and multi-day LEC treatment.