Adherence to antiemetic prophylaxis guidelines and the association with nausea/vomiting occurrence in breast cancer patients undergoing chemotherapy

This study aimed to examine the level of adherence to chemotherapy-induced nausea and vomiting (CINV) prophylaxis guidelines and its association with CINV occurrence at K Hospital. We conducted a prospective cohort study in breast cancer patients undergoing chemotherapy. Medication data for one treatment cycle were extracted from medical records to assess adherence to CINV prophylaxis guidelines based on international (NCCN 2024, ESMO 2016) and national (MOH 2019) recommendations. CINV events and associated risk factors were collected through structured patient interviews, while symptom occurrence and severity were assessed using the MASCC Antiemesis Tool (MAT). A multivariate logistic regression model was used to examine the association between guideline adherence and CINV risk, adjusted for patient characteristics. 118, 61, and 40 patients received high (HEC), medium (MEC), and low emetic chemotherapy (LEC), respectively. The overall incidence of CINV was 30.6% in the acute phase and 63.9% in the delayed phase. In the acute phase, 100% of HEC patients received under-prophylaxis, while 95% of LEC patients received over-prophylaxis. For delayed CINV prophylaxis, 84.7% of HEC patients received under-prophylaxis, and a majority of MEC patients had no prophylaxis (65.6%) or were under-prophylaxis (13.1%). Under-prophylaxis in the acute phase significantly increased the risk of acute CINV (OR [95% CI] 84.810 [10.122-710.0]; p<0.001), while in the delayed phase, both under-prophylaxis (OR [98%CI] 8.79 [3.72-20.74], p<0.001) and no prophylaxis (OR [95% CI] 2.85 [1.23-6.62]; p=0.015) significantly increased the risk of delayed CINV. Adherence to CINV prophylaxis guidelines at the study site was low, which was significantly associated with an increased risk of CINV events. These findings support strict adherence to guideline-based antiemetic regimens tailored to emetogenic risk, including consideration of cost-effective options such as olanzapine in resource-limited settings.