“…Pain is a symptom present in advanced stage cancer and its intensity varies according to the location, type of treatment and degree of evolution (Costa & Chaves, 2012). For this study, five articles related to cancer pain were selected and analysed, among which three performed randomised clinical trials, one carried out a pilot study with a retrospective design and one produced an observational study (Bao, Li, et al, 2018; Bao, Seidman, et al, 2018; Bao, Zhi, et al, 2018; Hershman et al, 2018; Kim & Lee, 2018; Meng & Feng, 2018; Ruela et al, 2018). In addition, the population selected for the randomised clinical trials ranged from 27 to 226 participants, while 592 people participated in the observational study (Bao, Li, et al, 2018; Bao, Seidman, et al, 2018; Bao, Zhi, et al, 2018).…”