Early and delayed intervention: definition

Patients were divided into the early CPN group—to receive the operation as soon as they fulfilled the criteria at the index visit, or the delayed group—those who underwent a wait-and-see analgesic titration and received CPN only when they developed persistent refractory pain or with intolerable adverse effects. This definition is based on the expert consensus from the Committee of Rehabilitation and Palliative Care of China, which identifies refractory cancer pain based on the following two criteria: (a) persistent pain score ≥4 and/or breakthrough pain ≥3 times/day and (b) unsatisfactory pain relief after at least 2 weeks of standardized medication and/or causes intolerable side effects (22).