SP56. The Impact of Cannabis Use On Autologous Breast Reconstruction: A Propensity Score Matched Analysis

PURPOSE: Since the recent legalization of cannabis across many U.S. states, cannabis use has increased dramatically.1 Previous studies examining the effect of cannabis use on autologous breast reconstruction report conflicting postoperative complications.2,3 This study leverages a large dataset to examine the impact of cannabis use on autologous breast reconstruction. METHODS: The TriNetX database, a deidentified database with data from over 250 million patients, was queried using CPT codes for autologous breast reconstruction and ICD/RXform codes for cannabis use. Patients with breast cancer who had undergone autologous breast reconstruction were stratified into two groups: cannabis users and non-users. To prevent confounders, these two groups were propensity score matched based on age, sex, demographics and other comorbidities. Associations with postoperative complications were analyzed with logistic regression. P-values <0.05 were considered statistically significant. RESULTS: TriNetX query revealed 17,853 non-users and 318 cannabis users. After propensity score matching, outcomes for 310 patients were examined at postoperative days 7, 30 and 90. Patients with cannabis use had a significantly increased risk of postoperative hematoma (p=0.001) and PE/DVT (p=0.001) at all three timepoints, as well as an increased risk of new opioid use (p=0.021), ED visits (p=0.001), and hospitalizations (p=0.036) at day 7, but not days 30 or 90. Non-users had a higher rate of flap failure (p=0.001) at days 7 and 30, though not day 90. No differences were seen between groups for postoperative infections, wound complications, seromas, or other vascular complications. Patients with cannabis use had a significantly higher risk of mortality (p=0.002) at day 90 but not day 7 or 30. CONCLUSION: Our results suggest that cannabis users undergoing autologous breast reconstruction are at increased risk of postoperative complications compared to non-users. Cannabis may have varying effects on hemostasis; this area requires further investigation. Cannabis users warrant further postoperative care and attention.