Differences in severity of chemotherapy-induced nausea and vomiting between neoadjuvant and adjuvant chemotherapy in patients with breast cancer: Analysis of data from two prospective observational studies

Abstract We assessed the differences in chemotherapy-induced nausea and vomiting (CINV) severity in patients with breast cancer, receiving neoadjuvant chemotherapy (NAC) and adjuvant chemotherapy (AC). CINV in patients receiving anthracycline-based NAC (n = 203) and AC (n = 174) was assessed before chemotherapy (C0), after the first and fourth chemotherapy, using a 10-point Likert scale. Group-time interaction term used to assess if group effect on changes in CIN (cCIN) and CIV (cCIV) from C0 to follow-up are similar over time. If not significant, group effect was evaluated in model without interaction term. Subgroup analysis were performed a based on age 50. The effect of group by follow-up period was not significant. Adjuvant chemotherapy was associated with a significantly higher change in severity of cCIN than neoadjuvant chemotherapy in the group effect (estimated mean difference = 0.888, p = 0.013). The two groups differed significantly between the severity of cCIN in those aged ≤ 50 years (estimated mean = 1.151, p = 0.009) but not in those aged > 50 years. NAC for breast cancer patients shows less severe CIN than AC, but not in middle-aged and above. Clinicians should recognize that CIN severity may vary across chemotherapy settings and manage accordingly.