Intra- and Interpatient Drug Response Heterogeneity Exist in Patients Undergoing Cytoreductive Surgery and Hyperthermic Intraperitoneal Chemotherapy for Nongynecologic Cancers.

BACKGROUND: Select patients with peritoneal metastases are treated with cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (CRS/HIPEC). We assayed for intra- and interpatient drug response heterogeneity through testing of patient-derived tumor organoids (PDTOs). METHODS: PDTOs were generated from CRS/HIPEC patients from December 2021 to September 2022 and subjected to an in vitro HIPEC drug screen. Drug response was assessed with a cell viability assay and cleaved caspase-3 staining. RESULTS: A total of 31 patients were consented for tissue collection. Viable tissue was harvested from 23, and PDTO generation was successful in 13 (56%). PDTOs were analyzed from six appendiceal, three colorectal, two small bowel, one gastric, and one adrenal tumor. Drug screen results were generated in as few as 7 days (62%), with an average time of 12 days. Most patients received mitomycin-C (MMC) intraoperatively (n = 9); however, in only three cases was this agent considered the optimal choice in vitro. Three sets of PDTOs were resistant (defined as > 50% PDTO viability) to all agents tested and two were pan-sensitive (defined as 3 or more agents with < 50% PDTO viability). In three patients, organoids were generated from multiple metastatic sites and intrapatient drug response heterogeneity was observed. CONCLUSIONS: Both intra- and interpatient drug response heterogeneity exist in patients undergoing CRS/HIPEC for nongynecologic abdominal cancers. Caution must be used when interpreting patient response to chemotherapeutic agents based on a single site of testing in those with metastatic disease.

Predictors of Financial Toxicity Risk Among Patients Undergoing Cytoreductive Surgery with Hyperthermic Intraperitoneal Chemotherapy (CRS-HIPEC).

BACKGROUND: Cytoreductive surgery with hyperthermic intraperitoneal chemotherapy (CRS-HIPEC) is the preferred treatment for select patients with peritoneal malignancies. However, the procedure is resource intensive and costly. This study aimed to determine the risk of financial toxicity for patients undergoing CRS-HIPEC. PATIENTS AND METHODS: We performed a retrospective cohort study of patients undergoing CRS-HIPEC at a single institution from 2016 to 2022. We utilized insurance status, out-of-pocket expenditures, and estimated post-subsistence income to determine risk of financial toxicity. A multivariable logistic regression was used to determine risk factors for financial toxicity. RESULTS: Our final study cohort consisted of 163 patients. Average age was 58 [standard deviation 10] years, and 52.8% (n = 86) were male. A total of 52 patients (31.9%) were at risk of financial toxicity. A total of 36 patients (22.1%) were from the lower income quartiles (first or second) and 127 patients (77.9%) were from the higher income quartiles (third or fourth). A total of 47 patients (29%) were insured by Medicare, and 116 patients (71%) had private insurance. The median out-of-pocket expenditure across the study cohort was $3500, with a median of $5000 ($3341-$7350) for the at-risk group and $3341 ($2500-$4022) for the not at-risk group (p < 0.001). Risk factors for financial toxicity included high out-of-pocket expenditures and a lower income quartile. CONCLUSIONS: An estimated one-third of patients undergoing CRS-HIPEC at our institution were at risk for financial toxicity. Several preoperative factors were associated with an increased risk and could be utilized to identify patients who might benefit from interventions.

Neighborhood-Level Socioeconomic Disadvantage Predicts Outcomes in Cytoreductive Surgery and Hyperthermic Intraperitoneal Chemotherapy for Peritoneal Malignancy.

BACKGROUND: Cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (CRS/HIPEC) improves survival in select patients with peritoneal metastases (PM), but the impact of social determinants of health on CRS/HIPEC outcomes remains unclear. PATIENTS AND METHODS: A retrospective review was conducted of a multi-institutional database of patients with PM who underwent CRS/HIPEC in the USA between 2000 and 2017. The area deprivation index (ADI) was linked to the patient's residential address. Patients were categorized as living in low (1-49) or high (50-100) ADI residences, with increasing scores indicating higher socioeconomic disadvantage. The primary outcome was overall survival (OS). Secondary outcomes included perioperative complications, hospital/intensive care unit (ICU) length of stay (LOS), and disease-free survival (DFS). RESULTS: Among 1675 patients 1061 (63.3%) resided in low ADI areas and 614 (36.7%) high ADI areas. Appendiceal tumors (n = 1102, 65.8%) and colon cancer (n = 322, 19.2%) were the most common histologies. On multivariate analysis, high ADI was not associated with increased perioperative complications, hospital/ICU LOS, or DFS. High ADI was associated with worse OS (median not reached versus 49 months; 5 year OS 61.0% versus 28.2%, P < 0.0001). On multivariate Cox-regression analysis, high ADI (HR, 2.26; 95% CI 1.13-4.50; P < 0.001), cancer recurrence (HR, 2.26; 95% CI 1.61-3.20; P < 0.0001), increases in peritoneal carcinomatosis index (HR, 1.03; 95% CI 1.01-1.05; P < 0.001), and incomplete cytoreduction (HR, 4.48; 95% CI 3.01-6.53; P < 0.0001) were associated with worse OS. CONCLUSIONS: Even after controlling for cancer-specific variables, adverse outcomes persisted in association with neighborhood-level socioeconomic disadvantage. The individual and structural-level factors leading to these cancer disparities warrant further investigation to improve outcomes for all patients with peritoneal malignancies.

Feasibility of cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) for advanced peritoneal surface tumors during the COVID-19 pandemic: A single-institution experience.

BACKGROUND AND OBJECTIVES: Cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) is a complex treatment used in selected patients with peritoneal surface malignancies. HIPEC procedures are time and resource intensive. The primary aim of this analysis was to compare the experience of treating advanced abdominal tumors with CRS-HIPEC before and during the coronavirus disease 2019 (COVID-19) pandemic. METHODS: Patients included in this analysis received CRS-HIPEC at a single center during either a prepandemic (March 18, 2019-March 17, 2020) or pandemic (March 18, 2020-February 5, 2021) interval. A retrospective chart review was performed. RESULTS: Our analysis included 67 patients: 30 (45%) treated prepandemic and 37 (55%) treated during the pandemic. Median age at the time of operation was 58 years (interquartile range: [49-65]); 53% of patients were women. Patients treated during the pandemic presented with higher peritoneal cancer index (PCI) scores with 32% (n = 12) having a PCI > 20 at the time of surgery (p = 0.01). Five patients had delays in surgery due to the pandemic. Rates of overall postoperative morbidity, reoperation, and readmission were not different between the cohorts. CONCLUSIONS: Despite presenting with more extensive disease, patients treated with CRS-HIPEC during the height of the COVID-19 pandemic had comparable perioperative outcomes to patients treated prepandemic.