Microsatellite instability should not determine candidacy for cytoreductive surgery and hyperthermic intraperitoneal chemoperfusion in patients with peritoneal metastases from colorectal cancer.

BACKGROUND: Cytoreductive surgery (CRS) plus hyperthermic intraperitoneal chemotherapy (HIPEC) is a multimodal therapeutic option for the management of peritoneal metastases (PM). Treatment outcomes for patients with colorectal cancer (CRC) PM undergoing CRS+HIPEC with microsatellite instability (MSI) remain unknown. We examined the patient characteristics and outcomes in patients with MSI CRC after CRS+HIPEC. METHODS: This was a retrospective cohort study of a prospectively maintained database of all patients with CRC PM undergoing CRS+HIPEC (2010-2020). Categorical and continuous variables were analyzed using the chi-square test and independent samples t test, respectively. Survival was evaluated with the Kaplan-Meier analysis. RESULTS: There were 324 patients diagnosed as having CRC PM undergoing CRS+HIPEC (MSI, n = 23; microsatellite stable [MSS], n = 301). There was no statistically significant difference in patient demographics, tumor characteristics, or perioperative factors between the 2 groups. There was a trend toward improved survival in the MSI group with a median overall survival (OS) of 96.7 month compared with patients with MSS disease (median OS, 51.4 months; P = .10). Patients with MSI demonstrated median progression-free survival (PFS) 8.5 months compared with 11.4 months in the MSS cohort (P = .28). CONCLUSION: Patients with CRC PM, regardless of MSI or MSS status, demonstrate similar OS and PFS after CRS+HIPEC. MSI status should not change a patient's candidacy for CRS+HIPEC.

Targeted Next-Generation Sequencing Improves the Prognostication of Patients with Disseminated Appendiceal Mucinous Neoplasms (Pseudomyxoma Peritonei).

BACKGROUND: Appendiceal mucinous neoplasms (AMNs) with disseminated disease (pseudomyxoma peritonei) are heterogeneous tumors with variable clinicopathologic behavior. Despite the development of prognostic systems, objective biomarkers are needed to stratify patients. With the advent of next-generation sequencing (NGS), it remains unclear if molecular testing can improve the evaluation of disseminated AMN patients. METHODS: Targeted NGS was performed for 183 patients and correlated with clinicopathologic features to include American Joint Committee on Cancer/World Health Organization (AJCC/WHO) histologic grade, peritoneal cancer index (PCI), completeness of cytoreduction (CC) score, and overall survival (OS). RESULTS: Genomic alterations were identified for 179 (98%) disseminated AMNs. Excluding mitogen-activated protein kinase genes and GNAS due to their ubiquitous nature, collective genomic alterations in TP53, SMAD4, CDKN2A, and the mTOR genes were associated with older mean age, higher AJCC/WHO histologic grade, lymphovascular invasion, perineural invasion, regional lymph node metastasis, and lower mean PCI (p < 0.040). Patients harboring TP53, SMAD4, ATM, CDKN2A, and/or mTOR gene alterations were found to have lower OS rates of 55% at 5 years and 14% at 10 years, compared with 88% at 5 years and 88% at 10 years for patients without the aforementioned alterations (p < 0.001). Based on univariate and multivariate analyses, genomic alterations in TP53, SMAD4, ATM, CDKN2A, and/or the mTOR genes in disseminated AMNs were a negative prognostic factor for OS and independent of AJCC/WHO histologic grade, PCI, CC score, and hyperthermic intraperitoneal chemotherapy treatment (p = 0.006). CONCLUSIONS: Targeted NGS improves the prognostic assessment of patients with disseminated AMNs and identifies patients who may require increased surveillance and/or aggressive management.

Failure to Thrive Following Cytoreduction and Hyperthermic Intraperitoneal Chemotherapy: Causes and Consequences.

BACKGROUND: Failure to thrive (FTT) is a complex syndrome of nutritional failure and functional decline. Readmission for FTT following cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (CRS HIPEC) is common but underexamined. This study aims to determine features, risk factors, and prognostic significance of FTT following CRS HIPEC. PATIENTS AND METHODS: We reviewed patients who underwent CRS HIPEC from 2010 to 2018 at our institution. Patients were categorized into no readmission, FTT readmission, and other readmission. FTT was determined by coding and chart review. We compared baseline characteristics, oncologic data, perioperative outcomes, and survival among the three cohorts. RESULTS: Of 1068 discharges examined, 379 patients (36%) were readmitted within 90 days, of which 134 (12.5%) were labeled as FTT. Patients with FTT readmission had worse preoperative functional status, higher rates of malnutrition, more complex resections, longer hospital stays, and more postoperative complications (all p < 0.001). Ostomy creation [relative risk ratio (RRR) 4.06], in-hospital venous thromboembolism (VTE), discharge to nursing home (RRR 2.48), pre-CRS HIPEC chemotherapy (RRR 1.98), older age (RRR 1.84), and female gender (RRR 1.69) were all independent predictors for FTT readmission on multinomial regression (all p < 0.01). FTT readmission was associated with worse median overall survival on multivariate analysis [hazard ratio (HR) 1.60, p < 0.001] after controlling for oncologic, perioperative, and baseline factors. CONCLUSIONS: FTT is common following CRS HIPEC and appears to be associated with baseline patient characteristics, operative burden, and postoperative complications. Perioperative strategies for improving nutrition and activity, along with early recognition and intervention in FTT may improve patient outcomes.

Definition and Prediction of Early Recurrence and Mortality Following Cytoreductive Surgery and Hyperthermic Intraperitoneal Chemotherapy for Colorectal Peritoneal Metastases: Towards Predicting Oncologic Futility Preoperatively.

INTRODUCTION: Early recurrence (ER) is a significant challenge for patients with colorectal peritoneal metastases (CRPM) following cytoreductive surgery with hyperthermic intraperitoneal chemotherapy (CRS HIPEC). Preoperative risk stratification for ER would improve preoperative decision making. METHODS: We conducted a retrospective study examining patients who underwent CRS HIPEC for CRPM from 2000 to 2018. Optimal definition of ER was determined via minimum p-value approach based on differentiation of post-recurrence survival. Risk factors for ER were assessed in a derivation cohort by uni- and multivariate logistic regression. A predictive score for ER was generated using preoperative variables and validated in an independent cohort. RESULTS: 384 patients were analyzed, 316 (82%) had documented recurrence. Optimal length of post-operative RFS to distinguish ER (n = 144, 46%) vs. late recurrence (LR) (n = 172, 63%) was 8 mos (p<0.01). ER patients had shorter median OS post-CRS-HIPEC (13.6 vs. 39.4 mos, p<0.01). Preoperative BMI (OR 1.88), liver lesions (OR 1.89), progression on chemotherapy (OR 2.14), positive lymph nodes (OR 2.47) and PCI score (16-20: OR 1.7; >20: OR 4.37) were significant predictors of ER (all p<0.05). Using this model, patients were assigned risk scores from 0 to 9. Intermediate (scores 4-6) and high-risk patients (score 7-9) had observed rates of ER of 56% and 79% and overall 2-year survival rates of 27% and 0% respectively. The model showed fair discrimination (AUC 0.72) and good calibration (Hosmer-Lemeshow GOF p = 0.68). CONCLUSIONS: ER predicts markedly worse OS following surgery. Preoperative factors can accurately stratify risk for ER and identify patients in whom CRS-HIPEC for CPRM is futile.

Impact of Socioeconomic Status on Presentation and Outcomes in Colorectal Peritoneal Metastases Following Cytoreduction and Chemoperfusion: Persistent Inequalities in Outcomes at a High-Volume Center.

BACKGROUND: Cytoreductive surgery and hyperthermic intraperitoneal chemoperfusion (CRS HIPEC) can offer significant survival advantage for select patients with colorectal peritoneal metastases (CRPM). Low socioeconomic status (SES) is implicated in disparities in access to care. We analyze the impact of SES on postoperative outcomes and survival at a high-volume tertiary CRS HIPEC center. PATIENTS AND METHODS: We conducted a retrospective cohort study examining patients who underwent CRS HIPEC for CRPM from 2000 to 2018. Patients were grouped according to SES. Baseline characteristics, perioperative outcomes, and survival were examined between groups. RESULTS: A total of 226 patients were analyzed, 107 (47%) low-SES and 119 (53%) high-SES patients. High-SES patients were younger (52 vs. 58 years, p = 0.01) and more likely to be White (95.0% vs. 91.6%, p = 0.06) and privately insured (83% vs. 57%, p < 0.001). They traveled significantly further for treatment and had lower burden of comorbidities and frailty (p = 0.01). Low-SES patients more often presented with synchronous peritoneal metastases (48% vs. 35%, p = 0.05). Following CRS HIPEC, low-SES patients had longer length of stay and higher burden of postoperative complications, 90-day readmission, and 30-day mortality. Median overall survival following CRS HIPEC was worse for low-SES patients (17.8 vs. 32.4 months, p = 0.02). This disparity persisted on multivariate survival analysis (low SES: HR = 1.46, p = 0.03). CONCLUSIONS: Despite improving therapies for CRPM, low-SES patients remain at a significant disadvantage. Even patients who overcome barriers to care experience worse short- and long-term outcomes. Improving access and addressing these disparities is crucial to ensure equitable outcomes and improve patient care.

Predischarge Prediction of Readmission After Cytoreductive Surgery and Hyperthermic Intraperitoneal Chemotherapy: Derivation and Validation of a Risk Prediction Score.

BACKGROUND: Ninety-day hospital readmission rates following cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (CRS/HIPEC) range from 20 to 40%. OBJECTIVE: The aim of this study was to develop and validate a simple score to predict readmissions following CRS/HIPEC. STUDY DESIGN: Using a prospectively maintained database, we retrospectively reviewed clinicopathologic, perioperative, and day-of-discharge data for patients undergoing CRS/HIPEC for peritoneal surface malignancies between 2010 and 2018. In-hospital mortalities and discharges to hospice were excluded. Multivariate logistic regression was utilized to identify predictors of unplanned readmission, with three-quarters of the sample randomly selected as the derivation cohort and one-quarter as the validation cohort. Using regression coefficient-based scoring methods, we developed a weighted 7-factor, 10-point predictive score for risk of readmission. RESULTS: Overall, 1068 eligible discharges were analyzed; 379 patients were readmitted within 90 days (35.5%). Seven factors were associated with readmission: stoma creation, Peritoneal Cancer Index score ≥ 15, hyponatremia, in-hospital major complication, preoperative chemotherapy, anemia, and discharge to nursing home. In the validation cohort, 25 patients (9.2%) were categorized as high risk for readmission, with a predicted rate of readmission of 69.3% and an observed rate of 76.0%. The score had fair discrimination (area under the curve 0.70) and good calibration (Hosmer-Lemeshow goodness-of-fit p-value of 0.77). CONCLUSION: Our proposed risk score, easily obtainable on day of discharge, distinguishes patients at high risk for readmission over 90 days following CRS/HIPEC. This score has the potential to target high-risk individuals for intensive follow-up and other interventions.