The Italian Questionnaire for Cancer Breakthrough Pain Diagnosis, a Multicenter Validation Study.

The IQ-BTP extensive formal validation showed satisfactory psychometric and validity properties. Its content, face, construct, and criterion validities and its reliability, interpretability, and responsiveness were shown. Its use enabled potential-BTcP to be identified and differentiated into three likelihood classes with direct therapeutic and epidemiological implications. The latter may be confirmed in future studies.