Transferability to clinical practice of the results of controlled clinical trials: The case of antiemetic prophylactic treatment for cancer chemotherapy-induced nausea and vomiting

Background: There is convincing evidence from randomized clinical trials that the use of 5-HT3 antagonists has brought about a substantial improvement in the control of chemotherapy-induced nausea and vomiting. However, no data exist to indicate how this new research evidence can be applied to the individual patient. Patients and methods. We carried out a prospective, observational study on the use and effectiveness of antiemetic drugs in patients undergoing cancer chemotherapy in 33 Italian oncology departments. Results: A total of 1,956 consecutive patients entered the study; 1,238 of them underwent a one-day chemotherapy and 718 a chemotherapy fractionated over several consecutive days. The 5-HT3 antagonists, used either alone or in combination with a corticosteroid, have almost completely supplanted all other types of antiemetic regimens for preventing cancer chemotherapy-induced emesis. In fact, 80% of patients, irrespective of whether their emesis was acute or delayed, or of the emetogenic potential of the cancer chemotherapy they received, have been treated with these compounds. However, the practice of participating oncologists with respect to prescriptions has been far from consistent with the evidence provided by randomized controlled trials. Both overtreatment and undertreatment have occurred in many patients, creating unjustified costs and placing the patients at greater risk for emesis. However, when antiemetics are properly used their effectiveness is similar to that seen in randomized controlled trials. Conclusions: Powerful barriers exist between the evidence provided by sound research and clinical practice, and this issue hampers progress toward the optimal use of antiemetic drugs.