Opioids and breast cancer recurrenceCronin-Fenton, DeirdreCurrent Opinion in Supportive and Palliative Care: June 2019 - Volume 13 - Issue 2 - p 88–93 doi: 10.1097/SPC.0000000000000426 PAIN: CANCER: Edited by Anthony H. Dickenson and Paul Farquhar-Smith Buy Abstract Author InformationAuthors Article MetricsMetrics Purpose of review Breast cancer survival has improved motivating the need for better understanding of the sequelae of the disease and its treatments. Lab studies suggest opioids modify cancer cell growth but the association of opioids with cancer progression in humans is not clear. This review aims to summarize recent findings related to opioid use and breast cancer progression. Recent findings Opioid-sparing analgesia may be associated with better survival in cancer patients. In-vitro research suggests that treatment with μ-opioid receptor antagonists inhibits cancer proliferation, and shows some promise for attenuating tumor growth in humans, thereby enhancing survival. Prescription use of opioids does not appear to influence the risk of recurrence in patients, though the evidence comes from a single large registry-based observational study. Ongoing clinical trials are comparing opioid-sparing regional anesthesia with general anesthesia for the risk of breast cancer recurrence. Summary The association of opioids with breast cancer progression is controversial. Further observational studies are needed. There is currently no clear evidence to suggest that opioid use should be avoided in breast cancer patients because of concerns regarding the risk of breast cancer recurrence. Department of Clinical Epidemiology, Aarhus University, Aarhus, Denmark Correspondence to Deirdre Cronin-Fenton, PhD, Associate Professor, Department of Clinical Epidemiology, Aarhus University, Olof Palmes Alle 43-45, 8200 Aarhus N., Denmark. Tel: +45 87168209; e-mail: firstname.lastname@example.org Copyright © 2019 Wolters Kluwer Health, Inc. All rights reserved.