Influence of body weight, age, and primary tumor site on opioid dose in advanced cancer pain patients

Abstract

Aim: The aim of this study was to evaluate the relationship between maximum opioid dose and body weight, age, and primary site in terminal cancer patients in a palliative care unit.
Methods: Medical records of 152 terminal cancer patients were reviewed retrospectively. Body weight, primary tumor site, age, and analgesic state were used as independent variables, and the maximum opioid dose was used as a dependent variable.
Results: There was no correlation between body weight and maximum opioid requirement. Selected independent variables were age and location of the primary lesion in the lower gastrointestinal tract. Maximum opioid dose was negatively correlated with age (P ≤0.0001) . Opioid needs of age <65 was 344.2mg/day oral morphine equivalent, but age 65-74 was 168.5, and age ≥75 was 116.9mg/day.
Conclusion: Elderly cancer patients required a lower amount of opioid analgesia than younger adults. The ratio for age <65, 65-74, and ≥75 was about 1 : 1/2 : 1/3.