https://www.selleckchem.com/products/ml-7.html g., a recurrent GBM tissue) where earlier treatment may have grossly altered the tumor microenvironment. Obese patients are at increased risk of persistent pain and chronic opioid dependence after surgery. We sought to evaluate the impact of an Enhanced Recovery After Surgery (ERAS) protocol in breast surgery patients to determine whether multimodal analgesia was effective for both obese and non-obese patients. A prospective cohort of patients undergoing breast surgery who received an opioid-sparing ERAS protocol was compared with patients who did not receive ERAS, including a historical cohort. Pain scores were compared with respect to body mass index (BMI). Obesity was defined as BMI ≥ 30, and moderate to severe pain was defined as 4-10 of a 10-point scale. Postoperative day one and week one pain scores were compared using the Kruskal-Wallis test. A combined contemporary and historical cohort of 1353 patients underwent lumpectomy and mastectomy without reconstruction. The present analysis comprises 622 patients with pain scores who did and did not receive ERAS between 2015 and 2018. The two groups were demographically similar. The day after surgery, those who received ERAS reported lower rates of moderate to severe pain, regardless of BMI (obese 46.3% vs. 21.8%, p < 0.001; non-obese 36.3% vs. 19.4%, p = 0.002). One week after surgery, obese patients who received ERAS had higher rates of persistent pain compared with non-obese patients (18.6% vs. 11.1%, p = 0.042). An opioid-sparing ERAS protocol utilizing multimodal analgesia significantly improved postoperative pain control for obese and non-obese patients. However, it appears that obese patients are still at relatively greater risk for persistent pain after surgery. An opioid-sparing ERAS protocol utilizing multimodal analgesia significantly improved postoperative pain control for obese and non-obese patients. However, it appears that obese patients are still at rel