Effect of present pain and mood on the memory of past postoperative pain in women treated surgically for breast cancer

In our recent retrospective study on breast cancer patients, the intensity of the past postoperative pain was a primary factor in predisposing the development of chronic post-treatment pain. The present prospective study was designed to find out if the remembered intensity of postoperative pain (RIPP) after breast surgery was influenced by the development of chronic pain and if the RIPP had any correlation with the development of depression or anxiety. The patient's estimation of the severity of the RIPP was determined three times in the year after surgery. The state anxiety and depression and the presence of pain in the ipsilateral arm were assessed before the operation, and 1, 6 and 12 mos after surgery. Ninety-three consecutive female patients with breast cancer who were enrolled for surgical treatment were recruited to the study during 1993-1994. The patients were treated with modified radical mastectomy with axillary clearance (n = 53) or breast resection with axillary clearance (n = 40). The patients' records were checked for the consumption of analgesics within the first 48 h after surgery. The patients were analysed in three groups according to the presence or absence of preoperative or chronic post-treatment pain. There was a significant correlation between the RIPP and the consumption of both opioids and NSAIDs on the ward. The women who had chronic pain remembered having had more severe postoperative pain compared with those women who had no chronic pain. The RIPP increased with time in the chronic pain patients whereas it decreased in the patients who had no chronic pain. In all patients the preoperatively measured state anxiety and depression scores were higher than in healthy Finnish women. One year after surgery anxiety and depression had returned to normal levels except in the patients who had chronic pain. Their depression remained at a higher level during the first year after surgery. The results suggest that the amount of postoperative pain may play a role in the development of chronic pain. However, the development of chronic pain is connected to a tendency to overestimate previous pain and to higher levels of depression.