Thompson, R. Houston

Objectives: To report the outcomes of minimally invasive (MIS) nephrectomy following immune checkpoint inhibitor (ICI) therapy. Materials and Methods: This multicenter retrospective cohort study included consecutive patients who underwent nephrectomy following ICI therapy at five high-volume US academic centers between 2015 and 2023. Baseline clinical features and perioperative findings were recorded. After propensity-score matching (PSM), outcomes were compared between MIS and open nephrectomies. The primary outcome was 90-day complications, and secondary outcomes included length of hospital stay (LOS) and 90-day readmission. Results: A total of 158 patients were included, of whom 76 and 82 underwent MIS and open nephrectomies, respectively. The MIS procedures included robotic ( n = 56) and laparoscopic ( n = 20). A total of six (8%) patients converted to open. On multivariable analysis, patients with nonmetastatic vs metastatic renal-cell carcinoma (RCC) (hazard ratio [HR] 3.1, p = 0.01), those with smaller tumor size (HR 1.2 for each cm, p = 0.001), and no clinical evidence of inferior vena cava thrombus (HR 29, p = 0.002) were more likely to undergo the MIS approach compared with open approach. After PSM, including 56 MIS and 36 open nephrectomies, the MIS group compared with the open group had lower estimated blood loss (100 vs 460 mL, p < 0.001) and shorter LOS (2 vs 4 days, p < 0.001). Nevertheless, 90-day complications and readmissions were similar between the two groups. There were no 90-day mortality rates in either group. Conclusion: The MIS approach appears safe and offers more favorable perioperative outcomes compared with open surgery in properly selected patients with advanced RCC who are candidates for nephrectomy following ICI therapy.

642 Background: Perioperative blood transfusion has been reported in up to 60% of patients undergoing RC. Unfortunately, perioperative blood transfusion in patient undergoing RC has been associated with poor oncological outcomes. Tranexamic acid (TXA) use has been proposed to decrease the need for perioperative blood transfusion. Here we seek to investigate the impact of intraoperative TXA on survival outcomes in patients undergoing radical cystectomy (RC) for bladder cancer. Methods: We queried the prospectively maintained Mayo Clinic Radical Cystectomy registry and identified all RC performed for bladder cancer between 1990-2021. Primary outcomes were patient’s overall survival and cancer specific survival among patients who received TXA versus patients who did not receive TXA. Results: Among 2929 patients who underwent RC in our institution between 1990-2021, 468 received TXA (IV) intraoperatively (Group A) and were propensity score matched 1:1 for age, neoadjuvant chemotherapy, adjuvant chemotherapy, pT stage, pN stage, and preoperative hemoglobin with a group who did not receive TXA (Group B, n= 468). At 8 years followup, 61% of patients who received TXA were alive versus 46% of patients who did not receive TXA. In univariable and multivariable analyses of factors associated with CSS (Table1), node positive disease, pT2-T4, peri-operative blood transfusion were associated with poor survival outcomes. While use of TXA was associated with improved CSS outcomes. Conclusions: In our study, TXA use in patients undergoing radical cystectomy was associated with decreased risk or peri-operative transfusion, improved patient’s overall survival, and cancer specific survival. We can’t explain the biological rational for improved survival however these findings warrant further prospective investigation. [Table: see text]

4657 Background: While active surveillance (AS) is well recognized as an acceptable treatment strategy for low-risk prostate cancer (PC), the extent to which radiation oncologists and urologists perceive AS as effective and routinely recommend it to patients is unknown. Therefore, we sought to assess the attitudes and treatment recommendations for low-risk PC from a national survey of PC specialists. Methods: A mail survey was sent to a population-based sample of 1,439 physicians in the U.S. from late 2011 and early 2012. Physicians were queried about their attitudes regarding AS and treatment recommendations for patients diagnosed with low-risk PC (PSA<10 ng/dl; T1c; Gleason 6 in one of twelve cores). Pearson Chi-square and multivariate logistic regression were used to test for differences in attitudes and treatment recommendations by physician demographics, compensation structure, primary place of employment, and specialty. Results: Overall, 321 radiation oncologists and 322 urologists completed the survey for a 45% response rate. Most physicians reported that AS is effective for low-risk PC (71%) and stated that they were comfortable routinely recommending AS (67%). Urologists were more likely to agree that AS is effective (77% vs. 67%; p=0.005) and were comfortable recommending AS (74% vs. 61%; p=0.001) compared with radiation oncologists. Most physicians recommended radical prostatectomy (47%) or radiation therapy (32%), but fewer endorsed AS (21%) for low-risk disease. After adjusting for physician covariates, radiation oncologists were more likely to recommend radiation therapy (OR: 10.97; p<0.001), while urologists were more likely to recommend surgery (OR: 4.69; p<0.001) and AS (OR: 2.18; p=0.001) for low-risk PC. Conclusions: Although AS is widely viewed as effective by both radiation oncologists and urologists, most urologists continue to recommend surgery, while most radiation oncologists recommend radiation therapy. Our results may explain in part the relatively low contemporary use of AS in the U.S.