Powers, Benjamin D.

ImportanceImmune checkpoint inhibitors (ICIs) have been approved for treatment of microsatellite instable (MSI-H) metastatic colorectal cancer (mCRC), but factors associated with receipt and efficacy of ICIs in routine clinical practice remain largely unknown.ObjectiveTo identify factors associated with receipt of ICIs and associated survival outcomes among patients with mCRC in routine clinical practice.Design, Setting, and ParticipantsThis population-based cohort study used deidentified data from a nationwide electronic health record–derived database to include 18 932 patients diagnosed with mCRC between January 2013 and June 2019. Population-based patients were diagnosed with de novo mCRC and had at least 2 documented clinical visits on or after the date of diagnosis. The study analyses were performed between September 2020 and April 2021.ExposurePatients received ICI therapy and/or chemotherapy as part of a systemic treatment for mCRC.Main Outcomes and MeasuresThe outcomes were receipt of ICI therapy, overall survival (OS), and time to treatment discontinuation (TTD).ResultsIn this cohort study of 18 932 patients diagnosed with mCRC (10 537 [55.7%] male; 546 [2.9%] Asian, 2005 [10.6%] Black or African American, 1674 [8.8%] Hispanic, 12 338 [65.2%] White, 4043 [21.4%] unknown race or ethnicity; median [IQR] age at metastatic diagnosis, 64.6 [55.0-73.3] years), patients with MSI-H tumors had a significantly higher probability of receiving ICIs than those with microsatellite stable (MSS) tumors (odds ratio [OR], 22.66 [95% CI, 17.30-29.73]; P < .001), whereas patients initially diagnosed with synchronous mCRC had significantly lower odds of receiving ICIs than patients with metachronous mCRC (OR, 0.57 [95% CI, 0.45-0.73]; P < .001). Patients with MSI-H tumors who received ICIs as first line of therapy had significantly longer OS than those receiving chemotherapy only (HR, 0.37 [95% CI, 0.25-0.56]; P < .001). Among patients with MSS tumors, ICI-based therapy was associated with significantly longer OS for patients with high albumin level (vs low: HR, 0.28 [95% CI, 0.18-0.45]; P < .001) and antibiotic use (vs nonuse: HR, 0.43 [95% CI, 0.27-0.67]; P < .001), but a significantly shorter OS for patients with synchronous mCRC (vs metachronous: HR, 1.90 [95% CI, 1.24-2.89]; P = .003). In addition, 29 out of 235 patients with MSS tumors (12.3%) experienced durable responses on ICI-based therapy. Similar patterns of associations with TTD were observed.Conclusions and RelevanceIn this cohort study of patients with mCRC, clinical characteristics were associated with different survival outcomes in patients treated with ICI-based therapy, with important clinical implications for patients with MSS tumors who are generally unresponsive to immunotherapy.

AbstractBackgroundWhile parenchymal hepatic metastases were previously considered a contraindication to cytoreductive surgery (CRS) and heated intraperitoneal chemotherapy (HIPEC), liver resection (LR) is increasingly performed with CRS/HIPEC.MethodsPatients from the US HIPEC Collaborative (2000–2017) with invasive appendiceal or colorectal adenocarcinoma undergoing primary, curative intent CRS/HIPEC with CC0‐1 resection were included. LR was defined as a formal parenchymal resection. Primary endpoints were postoperative complications and overall survival (OS).ResultsA total of 658 patients were included. About 83 (15%) underwent LR of colorectal (58%) or invasive appendiceal (42%) metastases. LR patients had more complications (81% vs. 60%; p = .001), greater number of complications (2.3 vs. 1.5; p < .001) per patient and required more reoperations (22% vs. 11%; p = .007) and readmissions (39% vs. 25%; p = .014) than non‐LR patients. LR patients had decreased OS (2‐year OS 62% vs. 79%, p < .001), even when accounting for peritoneal carcinomatosis index and histology type. Preoperative factors associated with decreased OS on multivariable analysis in LR patients included age < 60 years (HR, 3.61; 95% CI, 1.10–11.81), colorectal histology (HR, 3.84; 95% CI, 1.69–12.65), and multiple liver tumors (HR, 3.45; 95% CI, 1.21–9.85) (all p < .05). When assigning one point for each factor, there was an incremental decrease in 2‐year survival as the risk score increased from 0 to 3 (0: 100%; 1: 91%; 2: 58%; 3: 0%).ConclusionsAs CRS/HIPEC + LR has become more common, we created a simple risk score to stratify patients considered for CRS/HIPEC + LR. These data aid in striking the balance between an increased perioperative complication profile with the potential for improvement in OS.

AbstractBackgroundVariations in care have been demonstrated both within and among institutions in many clinical settings. By standardizing perioperative practices, Enhanced Recovery After Surgery (ERAS) pathways reduce variation in perioperative care. We sought to characterize the variation in cytoreductive surgery (CRS)/heated intraperitoneal chemotherapy (HIPEC) perioperative practices among experienced US medical centers.MethodsData from the US HIPEC Collaborative represents a retrospective multi‐institutional cohort study of CRS and CRS/HIPEC procedures performed from 12 major academic institutions. Patient characteristics and perioperative practices were reported and compared. Institutional variation was analyzed using hierarchical mixed‐effects linear (continuous outcomes) or logistic (binary outcomes) regression models.ResultsA total of 2372 operations were included. CRS/HIPEC was performed most commonly for appendiceal histologies (64.2%). The rate of complications (overall 56.3%, range: 31.8‐70.9) and readmissions (overall 20.6%, range: 8.9‐33.3) varied by institution (P < .001). Institution‐level variation in perioperative practice patterns existed among measured ERAS pathway process/outcomes (P < .001). The percentages of variation with each process/outcome measure attributable solely to institutional practices ranged from 0.6% to 66.6%.ConclusionsSignificant variation exists in the perioperative care of patients undergoing CRS/HIPEC at major US academic institutions. These findings provide a strong rationale for the investigation of best practices in CRS/HIPEC patients.

Cytoreductive surgery (CRS) with or without hyperthermic intraperitoneal chemotherapy (HIPEC) is associated with improved survival for patients with colorectal peritoneal metastases (CR-PM). However, the role of neoadjuvant chemotherapy (NAC) prior to CRS-HIPEC is poorly understood. A retrospective review of adult patients with CR-PM who underwent CRS+/-HIPEC from 2000–2017 was performed. Among 298 patients who underwent CRS+/-HIPEC, 196 (65.8%) received NAC while 102 (34.2%) underwent surgery first (SF). Patients who received NAC had lower peritoneal cancer index score (12.1 + 7.9 vs. 14.3 + 8.5, p = 0.034). There was no significant difference in grade III/IV complications (22.4% vs. 16.7%, p = 0.650), readmission (32.3% vs. 23.5%, p = 0.114), or 30-day mortality (1.5% vs. 2.9%, p = 0.411) between groups. NAC patients experienced longer overall survival (OS) (median 32.7 vs. 22.0 months, p = 0.044) but similar recurrence-free survival (RFS) (median 13.8 vs. 13.0 months, p = 0.456). After controlling for confounding factors, NAC was not independently associated with improved OS (OR 0.80) or RFS (OR 1.04). Among patients who underwent CRS+/-HIPEC for CR-PM, the use of NAC was associated with improved OS that did not persist on multivariable analysis. However, NAC prior to CRS+/-HIPEC was a safe and feasible strategy for CR-PM, which may aid in the appropriate selection of patients for aggressive cytoreductive surgery.

86 Background: Race and sex disparities exist for receipt of adjuvant chemotherapy (AC) for stage III colon cancer. However, most studies have not used an intersectional approach, which assesses the cumulative effects of different identities (e.g., Black women) instead of treating each as distinct, independent variables. Using this approach, we assessed the summative impact of these identities on receipt of AC for stage III colon cancer. Methods: The National Cancer Database was queried from 2004 to 2015 for patients who underwent surgery for stage III colon cancer and were healthy enough for AC. Receipt of AC was assessed chi-squared and multivariable logistic regression analyses. Results: 92,696 patients were identified. White patients had higher rates of care at community cancer centers. Black patients had higher rates of treatment at academic cancer programs (p < 0.001). Overall 83.5% received AC. Black males and females had higher rates of AC (86.5% and 86.2%, respectively) compared to White males and females (85.3% and 80.5%), respectively (p < 0.001). In adjusted analysis, Black males had the lowest odds of AC (OR 0.73), followed by Black females (OR 0.89) and White females (OR 0.91). When evaluated by age < 65 years and adjusting for potential confounders, Black men remained the least likely group to receive AC (OR 0.70). Black females had similar odds of receipt of AC (OR 0.99) and White females had increased odds (OR 1.22) relative to White males. Conclusions: Despite higher rates of treatment at academic centers, Black males and females had lower odds of receipt of AC after adjusting for confounders. Younger Black males persisted with the lowest odds of AC, although younger Black females had odds similar to younger White males. Additional research is necessary to identify drivers of these disparities and interventions to ameliorate them. [Table: see text]