Predicting severe pain following breast cancer surgery

A Cancer Research UK study has uncovered a simple way to predict which patients are most likely to experience severe pain in the wake of breast cancer surgery. It is hoped that the findings, published yesterday in the British Journal of Cancer, will enable medical professionals to identify those who would most benefit from additional pain relief during recovery.

A team of researchers from the Universities of Warwick, Aberdeen and Dundee surveyed 338 breast cancer patients across North Scotland. Prior to their surgery, participants completed detailed questionnaires concerning general health, how they were feeling and whether or not they were suffering from existing pain. One week after surgery, participants were asked specific questions about the amount and type of pain that they were experiencing and whether or not they had taken painkillers.

Following surgery, 41 per cent of patients reported experiencing moderate to severe pain whilst resting and half reported suffering from such pain during movement. The team found that women who previously suffered from other painful conditions, such as arthritis, lower back pain and migraines, were up to three times more likely to suffer severe pain in the week following surgery. The researchers also found that patients’ psychological states played an important role in determining the extent of pain experienced. Women who felt more optimistic before surgery were found to suffer lower intensity pain during the following week.

I spoke to study leader Dr Julie Bruce, Principal Research Fellow at the University of Warwick’s Clinical Trials Unit, to find out how her results can help patients recovering after breast cancer surgery. I began by asking whether it was the presence of preoperative pain or patients’ psychological states that had the most pronounced influence on the likelihood of postoperative pain.

"When we entered both factors into a statistical model, we found a 30 per cent reduced risk associated with psychological robustness and a threefold greater risk associated with preoperative pain," Dr Bruce explained. "In this sense, they were broadly equivalent. Previous literature, however, suggests that preoperative chronic pain has the greatest impact. This is something that can be targeted really easily. Clinical teams could screen preoperative patients to check whether they have a persistent pain condition. A lot of women are going to be experiencing pain when they arrive because they will have had investigative biopsies. However, we are specifically interested in chronic, long-term conditions such as arthritis and irritable bowel syndrome (IBS)."

I asked Dr Bruce whether it might be possible to treat patients prior to surgery, in order to reduce the likelihood of postoperative pain. As she explained, there are a number of approaches available.

"Patients with preoperative pain conditions may well be given more analgesia perioperativly or immediately afterwards," she said. "Rather than just a blanket treatment for all women, those with preoperative pain might be given stronger analgesia to dampen their pain responses to surgery.

"In terms of a patient’s psychological status, many women will be anxious before a procedure. The women most likely to suffer the highest intensities of pain following surgery are those with exceptionally high levels of preoperative anxiety and worry, and those who are less optimistic about their recovery. This can present more of a challenge, mainly because of the condition in question. Unlike elective procedures, there is not a huge time lag between diagnosis and surgery, and so you don’t really have a large window in which to intervene. There have been some studies concerning optimism. Researchers in the Netherlands are leading the way in this field. They are now setting up small trials to see whether it is possible to increase optimism. By giving patients psychological interventions for a period of six weeks prior to their procedures, the researchers are attempting to impact their acute and chronic post-operative outcomes. This is fairly novel work. There have also been interventions to try to reduce anxiety, such as psychological preparation. Generally, if patients have a good idea of what to expect, their anxiety will decrease."

I asked Dr Bruce whether she and her colleagues had tested for any other potential indicators that turned out not to influence the likelihood of postoperative pain.

"In previous literature, age has been identified as a contributing factor," she explained. "However, we did not find that that it had any impact in our study. Similarly, it has been suggested that the type of surgery can have an effect; that mastectomies might result in a higher risk of pain. However, when we compared lumpectomies with mastectomies, the difference was statistically insignificant."

I concluded our interview by asking Dr Bruce whether or not she plans to trial this new approach. She told me that it is important to conduct further research in order to maximise the long-term benefits brought about by preoperative screening.

"We now plan to investigate long-term outcomes because we have only really questioned women in their first week following surgery," said Dr Bruce. "There is fairly good evidence from other procedures to suggest that if you experience severe pain in the first week, you’re more likely to have chronic pain six to nine months later. If we can intervene early on, then we can potentially prevent chronic pain further down the line.

"We have also conducted previous studies in Grampian, although we didn’t assess patients preoperatively. We discovered that four years after surgery, 40 per cent of the women that we spoke to reported chronic pain symptoms. We followed up again at nine years and found that only half of the women who had chronic pain at four years had recovered. This really is a long process. We need to do whatever we can to prevent the onset and the persistence of pain."