Optimizing accrual to a large-scale, clinically integrated randomized trial in anesthesiology: A 2-year analysis of recruitment.

BACKGROUND: Performing large randomized trials in anesthesiology is often challenging and costly. The clinically integrated randomized trial is characterized by simplified logistics embedded into routine clinical practice, enabling ease and efficiency of recruitment, offering an opportunity for clinicians to conduct large, high-quality randomized trials under low cost. Our aims were to (1) demonstrate the feasibility of the clinically integrated trial design in a high-volume anesthesiology practice and (2) assess whether trial quality improvement interventions led to more balanced accrual among study arms and improved trial compliance over time. METHODS: This is an interim analysis of recruitment to a cluster-randomized trial investigating three nerve block approaches for mastectomy with immediate implant-based reconstruction: paravertebral block (arm 1), paravertebral plus interpectoral plane blocks (arm 2), and serratus anterior plane plus interpectoral plane blocks (arm 3). We monitored accrual and consent rates, clinician compliance with the randomized treatment, and availability of outcome data. Assessment after the initial year of implementation showed a slight imbalance in study arms suggesting areas for improvement in trial compliance. Specific improvement interventions included increasing the frequency of communication with the consenting staff and providing direct feedback to clinician investigators about their individual recruitment patterns. We assessed overall accrual rates and tested for differences in accrual, consent, and compliance rates pre- and post-improvement interventions. RESULTS: Overall recruitment was extremely high, accruing close to 90% of the eligible population. In the pre-intervention period, there was evidence of bias in the proportion of patients being accrued and receiving the monthly block, with higher rates in arm 3 (90%) compared to arms 1 (81%) and 2 (79%, p = 0.021). In contrast, in the post-intervention period, there was no statistically significant difference between groups (p = 0.8). Eligible for randomization rate increased from 89% in the pre-intervention period to 95% in the post-intervention period (difference 5.7%; 95% confidence interval = 2.2%-9.4%, p = 0.002). Consent rate increased from 95% to 98% (difference of 3.7%; 95% confidence interval = 1.1%-6.3%; p = 0.004). Compliance with the randomized nerve block approach was maintained at close to 100% and availability of primary outcome data was 100%. CONCLUSION: The clinically integrated randomized trial design enables rapid trial accrual with a high participant compliance rate in a high-volume anesthesiology practice. Continuous monitoring of accrual, consent, and compliance rates is necessary to maintain and improve trial conduct and reduce potential biases. This trial methodology serves as a template for the implementation of other large, low-cost randomized trials in anesthesiology.

Gabapentin and Rapidity of Recovery Among Patients Undergoing Minimally Invasive Ambulatory Uro-Oncologic Surgeries.

INTRODUCTION: Gabapentin has been used in enhanced recovery after surgery (ERAS) pathways for pain control for patients undergoing ambulatory uro-oncologic surgery; however, it may cause undesirable side effects. We studied the causal association between gabapentin and rapidity of recovery and perioperative pain management after minimally invasive uro-oncologic surgery. METHODS: We identified 2397 patients ≤ 65 years undergoing prostatectomies or nephrectomies between 2018 and 2022; 131 (5.5%) did not receive gabapentin. We tested the effect of gabapentin use on time of discharge and perioperative opioid consumption, respectively, using multivariable linear regression adjusting for potential confounders including age, gender, BMI, American Society of Anesthesiologists score, and surgery type. RESULTS: On adjusted analysis, we found no evidence of a difference in discharge time among those who did vs did not receive gabapentin (adjusted difference 0.07 hours shorter on gabapentin; 95% CI -0.17, 0.31; P = .6). There was no evidence of a difference in intraoperative opioid consumption by gabapentin receipt (adjusted difference -1.5 morphine milligram equivalents; 95% CI -4.2, 1.1; P = .3) or probability of being in the top quartile of postoperative opioid consumption within 24 hours (adjusted difference 4.2%; 95% CI -4.8%, 13%; P = .4). We saw no important differences in confounders by gabapentin receipt suggesting causal conclusions are justified. CONCLUSIONS: Our confidence intervals did not include clinically meaningful benefits from gabapentin, when used with an ERAS protocol, in terms of length of stay or perioperative opioid use. These results support the omission of gabapentin from ERAS protocols for minimally invasive uro-oncologic surgeries.

Reducing Disparities: Regional Anesthesia Blocks for Mastectomy with Reconstruction Within Standardized Regional Anesthesia Pathways.

BACKGROUND: Recent data suggest disparities in receipt of regional anesthesia prior to breast reconstruction. We aimed to understand factors associated with block receipt for mastectomy with immediate tissue expander (TE) reconstruction in a high-volume ambulatory surgery practice with standardized regional anesthesia pathways. PATIENTS AND METHODS: Patients who underwent mastectomy with immediate TE reconstruction from 2017 to 2022 were included. All patients were considered eligible for and were offered preoperative nerve blocks as part of routine anesthesia care. Interpreters were used for non-English speaking patients. Patients who declined a block were compared with those who opted for the procedure. RESULTS: Of 4213 patients who underwent mastectomy with immediate TE reconstruction, 91% accepted and 9% declined a nerve block. On univariate analyses, patients with the lowest rate of block refusal were white, non-Hispanic, English speakers, patients with commercial insurance, and patients undergoing bilateral reconstruction. The rate of block refusal went down from 12 in 2017 to 6% in 2022. Multivariable logistic regression demonstrated that older age (p = 0.011), Hispanic ethnicity (versus non-Hispanic; p = 0.049), Medicaid status (versus commercial insurance; p < 0.001), unilateral surgery (versus bilateral; p = 0.045), and reconstruction in earlier study years (versus 2022; 2017, p < 0.001; 2018, p < 0.001; 2019, p = 0.001; 2020, p = 0.006) were associated with block refusal. CONCLUSIONS: An established preoperative regional anesthesia program with blocks offered to all patients undergoing mastectomy with TE reconstruction can result in decreased racial disparities. However, continued differences in age, ethnicity, and insurance status justify future efforts to enhance preoperative educational efforts that address patient hesitancies in these subpopulations.

Regional Blocks Benefit Patients Undergoing Bilateral Mastectomy with Immediate Implant-Based Reconstruction, Even After Discharge.

BACKGROUND: There is limited evidence that regional anesthesia reduces pain in patients undergoing mastectomy with immediate implant-based reconstruction. We sought to determine whether regional blocks reduce opioid consumption and improve post-discharge patient-reported pain in this population. METHODS: We retrospectively reviewed patients who underwent bilateral mastectomy with immediate implant-based reconstruction with and without a regional block. We tested for differences in opioid consumption by block receipt using multivariable ordinal regression, and also assessed routinely collected patient-reported outcomes (PROs) for 10 days postoperatively and tested the association between block receipt and moderate or greater pain. RESULTS: Of 754 patients, 89% received a block. Non-block patients had an increase in the odds of requiring a higher quartile of postoperative opioids. Among block patients, the estimated probability of being in the lowest quartile of opioids required was 25%, compared with 15% for non-block patients. Odds of patient-reported moderate or greater pain after discharge was 0.54 times lower in block patients than non-block patients (p = 0.025). Block patients had a 49% risk of moderate or greater pain compared with 64% in non-block patients on postoperative day 5. There was no indication of any reason for these differences other than a causal effect of the block. CONCLUSION: Receipt of a regional block resulted in reduced opioid use and lower risk of self-reported moderate and higher pain after discharge in bilateral mastectomy with immediate implant-based reconstruction patients. Our use of PROs suggests that the analgesic effects of blocks persist after discharge, beyond the expected duration of a 'single shot' block.

Patient and procedure characteristics associated with postoperative pain after prophylactic versus therapeutic ambulatory bilateral breast surgery.

BACKGROUND AND OBJECTIVES: We investigated whether age, body mass index (BMI), and tissue expander placement were related to postoperative opioid requirement for patients undergoing therapeutic versus prophylactic breast surgery. METHODS: Postoperative opioid consumption was evaluated for patients who underwent bilateral mastectomy with immediate implant-based reconstruction at a freestanding ambulatory cancer surgery center between 2016 and 2021. Ordinal regression tested whether surgical indication was associated with increased postoperative opioid requirements after adjusting for age, BMI, and tissue expander placement. RESULTS: Of 2447 patients, 6% underwent prophylactic surgeries. Therapeutic mastectomy patients had lower postoperative opioid requirement (OR = 0.67; 95% CI: 0.50-0.91; p = 0.030), but this was not significant after adjusting for covariates (OR = 0.75; 95% CI: 0.53-1.07; p = 0.2). Opioid use increased with higher BMI (OR = 1.06; 95% CI: 1.05-1.08; p < 0.001) and decreased with age (OR = 0.97; 95% CI: 0.96-0.98; p < 0.001) with therapeutic mastectomy patients being older (median 46 vs. 39). The subpectoral tissue expander group had nearly double the postoperative opioid requirement compared to prepectoral placement (OR = 1.86; 95% CI: 1.55-2.23; p < 0.001). CONCLUSIONS: Increased postoperative opioid requirement in women undergoing prophylactic procedures is best explained by age. Mastectomy patients should be counseled similarly about postoperative pain irrespective of indication. A larger prophylactic mastectomy sample is required to provide more precise estimates.

Paravertebral Blocks in Tissue Expander Breast Reconstruction: Propensity-Matched Analysis of Opioid Consumption and Patient Outcomes.

BACKGROUND: The paravertebral block (PVB) is an adjunctive perioperative pain control method for patients undergoing breast reconstruction that may improve perioperative pain control and reduce narcotic use. This study determined the efficacy of preoperative PVBs for perioperative pain management in patients undergoing tissue expander breast reconstruction. METHODS: A retrospective review was performed of patients who underwent tissue expander breast reconstruction from December of 2017 to September of 2019. Two patients with PVBs were matched using propensity scoring to one no-block patient. Perioperative analgesic use, pain severity scores on days 2 to 10 after discharge, and BREAST-Q Physical Well-Being scores before surgery and at 2 weeks, 6 weeks, and 3 months after surgery were compared between the two groups. RESULTS: The propensity-matched cohort consisted of 471 patients (314 PVB and 157 no block). The PVB group used significantly fewer morphine milligram equivalents than the no-block group (53.7 versus 69.8; P < 0.001). Average daily postoperative pain severity scores were comparable, with a maximum difference of 0.3 points on a 0-point to 4-point scale. BREAST-Q Physical Well-Being scores were significantly higher for the PVB group than the no-block group at 6 weeks after surgery (60.6 versus 51.0; P = 0.015) but did not differ significantly at 2 weeks or 3 months after surgery. CONCLUSIONS: PVBs may help reduce perioperative opioid requirements but did not reduce pain scores after discharge when used as part of an expander-based reconstruction perioperative pain management protocol. Continued research should examine additional or alternative regional block procedures as well as financial cost and potential long-term impact of PVBs. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, III.

An Enhanced Ambulatory Surgery Experience for Patients with Cancer Through End-to-End Patient Engagement.

Ambulatory surgery centers (ASC) serve an important role for hospital systems of increasing operating capacity and offloading patient volume. When seeking to perform more complex cancer surgeries at an ASC, a systematic approach with care pathways can yield success by facilitating quick recovery for patients and reducing complication rates. End-to-end patient engagement is a key component of patient-centered care at the Josie Robertson Surgery Center and begins the moment the decision to have surgery is made and extends to the postdischarge period to track recovery. Engagement includes comprehensive education, standardization of processes, and setting clear expectations for recovery and discharge.

How Much Pain Will I Have After Surgery? A Preoperative Nomogram to Predict Acute Pain Following Mastectomy.

INTRODUCTION: Acute postoperative pain affects time to opioid cessation and quality of life, and is associated with chronic pain. Effective screening tools are needed to identify patients at increased risk of experiencing more severe acute postoperative pain, and who may benefit from multimodal analgesia and early pain management referral. In this study, we develop a nomogram to preoperatively identify patients at high risk of moderate-severe pain following mastectomy. METHODS: Demographic, psychosocial, and clinical variables were retrospectively assessed in 1195 consecutive patients who underwent mastectomy from January 2019 to December 2020 and had pain scores available from a post-discharge questionnaire. We examined pain severity on postoperative days 1-5, with moderate-severe pain as the outcome of interest. Multivariable logistic regression was performed to identify variables associated with moderate-severe pain in a training cohort of 956 patients. The final model was determined using the Akaike information criterion. A nomogram was constructed using this model, which also included a priori selected clinically relevant variables. Internal validation was performed in the remaining cohort of 239 patients. RESULTS: In the training cohort, 297 patients reported no-mild pain and 659 reported moderate-severe pain. High body mass index (p = 0.042), preoperative Distress Thermometer score ≥4 (p = 0.012), and bilateral surgery (p = 0.003) predicted moderate-severe pain. The resulting nomogram accurately predicted moderate-severe pain in the validation cohort (AUC =  0.735). CONCLUSIONS: This nomogram incorporates eight preoperative variables to provide a risk estimate of acute moderate-severe pain following mastectomy. Preoperative risk stratification can identify patients who may benefit from individually tailored perioperative pain management strategies and early postoperative interventions to treat pain and assist with opioid tapering.

The Use of Pectoralis Blocks in Breast Surgery: A Practice Advisory and Narrative Review from the Society for Ambulatory Anesthesia (SAMBA).

Although pectoralis (PECS) blocks are commonly used for breast surgery, recommendations regarding the efficacy of these blocks have thus far not been developed by any professional anesthesia society. Given the potential impact of PECS blocks on analgesia after outpatient breast surgery, The Society for Ambulatory Anesthesia (SAMBA) convened a task force to develop a practice advisory on the use of this analgesic technique. In this practice advisory, we compare the efficacy of PECS blocks with systemic analgesia, local infiltration anesthesia, and paravertebral blockade. Our objectives were to advise on two clinical questions. (1) Does PECS-1 and/or -2 blockade provide more effective analgesia for breast-conserving surgery than either systemic analgesics or surgeon-provided local infiltration anesthesia? (2) Does PECS-1 and/or -2 blockade provide equivalent analgesia for mastectomy compared with a paravertebral block (PVB)? Among patients undergoing breast-conserving surgery, PECS blocks moderately reduce postoperative opioid use, prolong time to analgesic rescue, and decrease postoperative pain scores when compared with systemic analgesics. SAMBA recommends the use of a PECS-1 or -2 blockade in the absence of systemic analgesia (Strength of Recommendation A). No evidence currently exists that strongly favors the use of PECS blocks over surgeon-performed local infiltration in this surgical population. SAMBA cannot recommend PECS blocks over surgical infiltration (Strength of Recommendation C). For patients undergoing a mastectomy, a PECS block may provide an opioid-sparing effect similar to that achieved with PVB; SAMBA recommends the use of a PECS block if a patient is unable to receive a PVB (Strength of Recommendation A).

Enhanced Recovery Programs in an Ambulatory Surgical Oncology Center.

BACKGROUND: We describe the implementation of enhanced recovery after surgery (ERAS) programs designed to minimize postoperative nausea and vomiting (PONV) and pain and reduce opioid use in patients undergoing selected procedures at an ambulatory cancer surgery center. Key components of the ERAS included preoperative patient education regarding the postoperative course, liberal preoperative hydration, standardized PONV prophylaxis, appropriate intraoperative fluid management, and multimodal analgesia at all stages. METHODS: We retrospectively reviewed data on patients who underwent mastectomy with or without immediate reconstruction, minimally invasive hysterectomy, thyroidectomy, or minimally invasive prostatectomy from the opening of our institution on January 2016 to December 2018. Data collected included use of total intravenous anesthesia (TIVA), rate of PONV rescue, time to first oral opioid, and total intraoperative and postoperative opioid consumption. Compliance with ERAS elements was determined for each service. Quality outcomes included time to first ambulation, postoperative length of stay (LOS), rate of reoperation, rate of transfer to acute care hospital, 30-day readmission, and urgent care visits ≤30 days. RESULTS: We analyzed 6781 ambulatory surgery cases (2965 mastectomies, 1099 hysterectomies, 680 thyroidectomies, and 1976 prostatectomies). PONV rescue decreased most appreciably for mastectomy (28% decrease; 95% confidence interval [CI], -36 to -22). TIVA use increased for both mastectomies (28%; 95% CI, 20-40) and hysterectomies (58%; 95% CI, 46-76). Total intraoperative opioid administration decreased over time across all procedures. Time to first oral opioid decreased for all surgeries; decreases ranged from 0.96 hours (95% CI, 2.1-1.4) for thyroidectomies to 3.3 hours (95% CI, 4.5 to -1.7) for hysterectomies. Total postoperative opioid consumption did not change by a clinically meaningful degree for any surgery. Compliance with ERAS measures was generally high but varied among surgeries. CONCLUSIONS: This quality improvement study demonstrates the feasibility of implementing ERAS at an ambulatory surgery center. However, the study did not include either a concurrent or preintervention control so that further studies are needed to assess whether there is an association between implementation of ERAS components and improvements in outcomes. Nevertheless, we provide benchmarking data on postoperative outcomes during the first 3 years of ERAS implementation. Our findings reflect progressive improvement achieved through continuous feedback and education of staff.

Intraoperative Ketorolac is Associated with Risk of Reoperation After Mastectomy: A Single-Center Examination.

BACKGROUND: Although ketorolac is an effective adjunct for managing pain in the perioperative period, it is associated with a risk of postoperative bleeding. This study retrospectively investigated the association between ketorolac use and both reoperation and postoperative opioid use among mastectomy patients. METHODS: The study identified all women undergoing mastectomy (unilaterally or bilaterally) at our ambulatory surgery cancer center from January 2016 to June 2019. The primary outcome was reoperation for bleeding on postoperative day 0 or 1, and the secondary outcome was postoperative opioid use. The association between ketorolac and outcomes was assessed using multivariable regression models. The covariates were age, body mass index, breast reconstruction, bilateral surgery, peripheral nerve block, and preoperative antiplatelet and/or anticoagulation medication. RESULTS: A cohort of 3469 women were identified. Ketorolac was given to 1549 (45%) of the women, with 922 women (60%) receiving 30 mg and 627 women (40%) receiving 15 mg. The overall reoperation rate for bleeding was 3.1% (1.8% without ketorolac vs 4.8% with ketorolac). In the multivariable analysis, ketorolac was associated with a higher risk of reoperation [odds ratio (OR) 2.43; 95% confidence interval (CI) 1.60-3.70; P < 0.0001]. Ketorolac also was associated with a lower proportion of patients receiving any postoperative narcotic within 24 h (15 mg: OR 0.73; 95% CI 0.57-0.94; P = 0.014 vs 30 mg: OR 0.52; 95% CI 0.42-0.66; P < 0.0001). CONCLUSIONS: Ketorolac use decreased postoperative opioid use, but this benefit was outweighed by the increased risk of bleeding requiring reoperation. This finding led to a change in practice at the authors' center, with ketorolac no longer administered in the perioperative care of the mastectomy patient.

Trends in Peripheral Nerve Block Usage in Mastectomy and Lumpectomy: Analysis of a National Database From 2010 to 2018.

BACKGROUND: Compared to general anesthesia, regional anesthesia confers several benefits including improved pain control and decreased postoperative opioid consumption. While the benefits of peripheral nerve blocks (PNB) have been well studied, there are little epidemiological data on PNB usage in mastectomy and lumpectomy procedures. The primary objective of our study was to assess national trends of the annual proportion of PNB use in breast surgery from 2010 to 2018. We also identified factors associated with PNB use for breast surgery. METHODS: We identified lumpectomy and mastectomy surgical cases with and without PNB between 2010 and 2018 using the Anesthesia Quality Institute National Anesthesia Clinical Outcomes Registry (AQI NACOR). We modeled the nonlinear association between year of procedure and PNB use with segmented mixed-effects logistic regression clustered on facility identifier. The association between PNB use and year of procedure, age, sex, American Society of Anesthesiologists physical status (ASA PS), facility type, facility region, weekday, and tissue expander use was also modeled using mixed-effects logistic regression. RESULTS: Of the 189,854 surgical cases from 2010 to 2018 that met criteria, 86.2% were lumpectomy cases and 13.8% were mastectomy cases. The proportion of lumpectomy cases with PNB was <0.1% in 2010 and increased each subsequent year to 1.9% in 2018 (trend P < .0001). The proportion of mastectomy cases with PNB was 0.5% in 2010 and 13% in 2018 (trend P < .0001). The year 2014 was the breakpoint selected for segmented regression. Before 2014, the odds of PNB among the mastectomy cases was not significantly different from year to year. After 2014, the odds of PNB increased by 2.24-fold each year (95% confidence interval [CI], 2.00-2.49; P < .001); interaction test for pre-2014 versus post-2014 was P < .001. Similar trends were seen in the lumpectomy cases, where after 2014, the odds of PNB increased by 2.03-fold (95% CI, 1.81-2.27; P < .001); interaction test for pre-2014 versus post-2014 was P < .001. In the mastectomy cohort, year of procedure ≥2014, female sex, facility region, and tissue expander use were associated with higher odds of PNB. For lumpectomy cases, year of procedure ≥2014 and facility region were associated with higher odds of PNB use. CONCLUSIONS: We found increased annual utilization of PNB for mastectomy and lumpectomy since 2010, although absolute prevalence is low. PNB use was associated with year of procedure for both lumpectomy and mastectomy, particularly post-2014.

Complex Cancer Surgery in the Outpatient Setting: The Josie Robertson Surgery Center.

Minimally invasive operative techniques and enhanced recovery after surgery (ERAS) protocols have transformed clinical practice and made it possible to perform increasingly complex oncologic procedures in the ambulatory setting, with recovery at home after a single overnight stay. Capitalizing on these changes, Memorial Sloan Kettering Cancer Center's Josie Robertson Surgery Center (JRSC), a freestanding ambulatory surgery facility, was established to provide both outpatient procedures and several surgeries that had previously been performed in the inpatient setting, newly transitioned to this ambulatory extended recovery (AXR) model. However, the JRSC core mission goes beyond rapid recovery, aiming to be an innovation center with a focus on superlative patient experience and engagement, efficiency, and data-driven continuous improvement. Here, we describe the JRSC genesis, design, care model, and outcome tracking and quality improvement efforts to provide an example of successful, patient-centered surgical care for select patients undergoing relatively complex procedures in an ambulatory setting.

Non-narcotic Perioperative Pain Management in Prosthetic Breast Reconstruction During an Opioid Crisis: A Systematic Review of Paravertebral Blocks.

BACKGROUND: Alternatives to postoperative, narcotic pain management following implant-based, postmastectomy breast reconstruction (IBR) must be a focus for plastic surgeons and anesthesiologists, especially with the current opioid epidemic. Paravertebral blocks (PVBs) are a regional technique that has demonstrated efficacy in patients undergoing a variety of breast cancer-related surgeries. However, a specific understanding of PVB's efficacy in pain management in patients who undergo IBR is lacking. METHODS: A systematic search of PubMed, EMBASE, and Cochrane Library electronic database was conducted to examine PVB administration in mastectomy patients undergoing IBR. Data were abstracted regarding: authors, publication year, study design, patient demographics, tumor laterality, tumor stage, type, and timing of reconstruction. The primary outcome was PVB efficacy, represented as patient-reported pain scores. Secondary outcomes of interest include narcotic consumption, postoperative nausea and vomiting, antiemetic use, and length of stay. RESULTS: The search resulted in 1,516 unique articles. After title and abstract screening, 29 articles met the inclusion criteria for full-text review. Only 7 studies were included. Of those, 2 studies were randomized control trials and 5 were retrospective cohort studies. Heterogeneity of included studies precluded a meta-analysis. Overall, PVB patients had improved pain control, and less opioid consumption. CONCLUSION: PVBs are a regional anesthesia technique which may aid in pain management in the breast reconstructive setting. Evidence suggests that PVBs aid in controlling acute postoperative pain, reduce opioid consumption, and improve patient length of stay. However, some conflicting findings demonstrate a need for continued research in this area of pain control.

Suitability of outpatient or ambulatory extended recovery cancer surgeries for obese patients.

STUDY OBJECTIVE: An increasing number of overweight and obese patients are presenting for ambulatory surgical procedures and may be at risk of complications including longer surgeries, longer length of stay (LOS), and possible increase in unanticipated return visits or hospital admissions. DESIGN: Observational study using prospectively-collected data. SETTING: Freestanding and hospital-based ambulatory surgery facilities. PATIENTS AND INTERVENTIONS: 13,957 patients underwent ambulatory cancer surgery procedures at the Josie Robertson Surgery Center (JRSC) since opening in 2016, and 4591 patients eligible for ambulatory surgery at JRSC underwent surgery at the main hospital during the same timeframe. MEASUREMENTS: We assessed whether BMI was associated with increased operative time, post-operative LOS, hospital transfer after surgery, or hospital readmission or urgent care center visits within 30 days. Using multivariable logistic regression, we assessed whether BMI was associated with decision to do surgery at JRSC controlling for age, ASA score and surgical service. MAIN RESULTS: While higher BMI was associated with a higher rate of transfer out of JRSC (p = 0.014), the difference in rate was small (mean risk 0.8% for BMI 25 vs 1.3% for BMI 40, difference in risk 0.52%, 95% CI 0.05%, 1.0%). We found no evidence that higher BMI increased the risk of urgent care visits or readmissions within 30 days or outpatient LOS (p = 0.7 for all). There was a statistically but not clinically significant difference in operative time for outpatient procedures (p = <0.0001), with a mean operative time of 59 vs 63 min for BMI 25 vs 40. Ambulatory extended recovery patients with higher BMI had shorter operative times (p < 0.0001). Patients with higher BMI were not significantly less likely to undergo surgery at JRSC (84% vs 83% vs 82% probability of treatment at JRSC for BMI 25, BMI 40 or BMI 50, respectively, p = 0.089). CONCLUSIONS: Ambulatory cancer surgeries can be performed safely among clinically eligible patients. Patients with BMI up to 50 or more can be treated safely in an ambulatory setting if they otherwise meet eligibility criteria.