“…For instance, the study performed by Triana and collaborators [ 82 ] presents a lower weight in the meta-analysis because of its small sample size. The issue of pain assessment is even more important for aged populations with cognitive decline, needing suitable observational tools [ 90 , 91 , 92 ], as well as valid and reliable methods with good psychometric and clinimetric properties in this setting, and deserving consideration for additional sources of pain and their treatment [ 93 , 94 , 95 , 96 , 97 ]. In addition, different cancer types can influence pain, thus making the comparison more difficult.…”