SEOM clinical guideline emesis (2021).

Among the side effects of anticancer treatment, chemotherapy-induced nausea and vomiting (CINV) is one of the most feared given its high prevalence, affecting up to 40% of patients. It can impair patient's quality of life and provoke low adherence to cancer treatment or chemotherapy dose reductions that can comprise treatment efficacy. Suffering CINV depends on factors related to the intrinsic emetogenicity of antineoplastic drugs and on patient characteristics. CINV can appear at different times regarding the administration of antitumor treatment and the variability of risk according to the different antitumor regimens has, as a consequence, the need for a different and adapted antiemetic treatment prophylaxis to achieve the desired objective of complete protection of the patient in the acute phase, in the late phase and in the global phase of emesis. As a basis for the recommendations, the level of emetogenicity of anticancer treatment is considered and they are classified as high, moderate, low and minimal emetogenicity and these recommendations are based on the use of antiemetic drugs with a high therapeutic index: anti 5-HT, anti-NK and steroids. Despite having highly effective treatments, clinical reality shows that they are not applied enough, so evidence-based recommendations are needed to show the best options and help in decision-making. To cover all the antiemetic prophylaxis options, we have also included recommendations for oral treatments, multiday regimens and radiation-induced emesis prevention.