Gjeilo KH, et al. - Researchers investigated the pain trajectory in patients undergoing surgery for primary lung cancer. In addition, they examined whether different pain trajectories relate to distinct groups of patients. They identified an increase in the occurrence of any pain from 40% before surgery to 69% after 1 month, and a decrease in pain occurrence to 56%, 57%, and 55% at 5, 9, and 12 months, respectively. This indicates a high prevalence of pain after surgery. Using latent class mixed models, two classes were identified both for average and worst pain: one class started low with high ratings after one month, then returning to a level slightly higher than baseline; the other class started higher with similar scores through the trajectory. Patients reporting no pain (8%) were placed in a separate class. The class with overall highest pain for average and/or worst pain exhibited the following characteristics: higher comorbidity score, preoperative use of pain and psychotropic medicine.