Survival Outcomes for Malignant Peritoneal Mesothelioma at Academic Versus Community Hospitals

Patient Complexity, Social Factors, and Hospitalization Outcomes at Academic and Community Hospitals

Importance

There have been limited evaluations of the patients treated at academic and community hospitals. Understanding differences between academic and community hospitals has relevance for the design of clinical models of care, remuneration for clinical services, and health professional training programs.

Objective

To evaluate differences in complexity and clinical outcomes between patients admitted to general medical wards at academic and community hospitals.

Design, Setting, and Participants

This retrospective cohort study of patients admitted to general medicine at 28 hospitals in Ontario, Canada, was conducted between April 2015 and December 2021. All patients admitted to or discharged from general medicine during the study period who were older than 18 years were included. Data analysis occurred between February 2023 and June 2024.

Exposures

Patient admission to a general medicine inpatient service at an academic or community hospital.

Main Outcomes and Measures

Demographic and clinical characteristics (age, sex, modified Laboratory-based Acute Physiology Score [mLAPS], discharge diagnosis, Charlson Comorbidity Index, frailty risk score, and disability), social factors (neighborhood-level markers of income, material deprivation, immigrant status, and racial and ethnic minority status) and clinical outcomes and processes (patient volume per physician, in-hospital mortality, length of stay, readmission rates, and intensive care unit [ICU] admission rates).

Results

There were 947 070 admissions, including 609 696 at 17 community hospitals (median [IQR] age, 73 [58-84] years) and 337 374 at 11 academic hospitals (median [IQR] age, 70 [56-82] years). Baseline clinical characteristics were similar at community and academic hospitals, including female sex (307 381 [50.4%] vs 168 033 [49.8%]; standardized mean difference [SMD] = 0.012), median (IQR) mLAPS (21 [11-36] vs 21 [10-34]; SMD = 0.001), and Charlson Comorbidity Index score of 2 or greater (182 171 [29.9%] vs 105 502 [31.3%]; SMD = 0.038). Social characteristics, including income, education, and neighborhood proportion of racial and ethnic minority and immigrant residents were also similar. The number of unique discharge diagnoses was similar at academic and community hospitals. Patient volumes per attending physician were higher at academic hospitals (median [IQR] daily census, 20 [19-22] vs 17 [15-19]; SMD = 1.086). After multivariable regression adjusting for baseline factors, mortality (adjusted odds ratio [aOR], 0.96; 95% CI, 0.78 to 1.17), ICU admission rate (aOR, 1.20; 95% CI, 0.80 to 1.79) and length of stay (β =  -0.001; 95% CI, -0.10 to 0.10) were not significantly different, while 7-day readmission (aOR, 1.25; 95% CI, 1.10 to 1.43) and 30-day readmission (aOR, 1.25; 95% CI, 1.10 to 1.42) were significantly higher at academic hospitals than community hospitals.

Conclusions and Relevance

In this cohort study, patients admitted to general medicine at academic and community hospitals had similar baseline clinical characteristics and generally similar clinical outcomes, with greater readmission rates in academic hospitals. These findings suggest that the patient case mix in general internal medicine that trainees would be exposed to during their residency training at academic hospitals is largely representative of the case mix they would encounter at community hospitals, and has important implications for health services planning and funding.

Pediatric, Adolescent and Young Adult (AYA) Peritoneal and Pleural Mesothelioma: A National Cancer Database Review

PURPOSE

Malignant peritoneal and pleural mesothelioma are rare in young patients, with a paucity of data regarding clinical characteristics and outcomes. We aimed to describe the clinical characteristics, treatment strategies, and outcomes for pediatric and adolescent/young adult (AYA) patients.

METHODS

The National Cancer Database (NCDB) was queried for malignant peritoneal and pleural mesothelioma in pediatric and AYA patients (ages 0-39) from 2004 to 2019. Stratification was performed for pediatric (age 0-21) and young adult (age 22-39) patients. Chi-squared, multivariable cox regression, and Kaplan-Meier analyses were performed.

RESULTS

We identified 570 total patients, 46 pediatric and 524 young adult, with mesothelioma (363 peritoneal and 207 pleural). There were significant differences in sex distribution as patients with peritoneal mesothelioma were more frequently female (63.1%). Patients with peritoneal mesothelioma were more likely to have radical surgery compared to pleural mesothelioma (56.7% v. 24.6%, respectively). A majority of patients with peritoneal and pleural mesothelioma received chemotherapy (66.4% and 61.4%, respectively). For peritoneal mesothelioma, surgical resection was associated with improved overall survival, whereas male sex, neoadjuvant chemotherapy, and radiation were associated with worse overall survival. For pleural mesothelioma, intraoperative chemotherapy was associated with improved overall survival, whereas Black race was associated with worse overall survival. Mean overall survival was greater for patients with peritoneal mesothelioma (125 months) compared to those with pleural mesothelioma (69 months), which remained significant after stratification of pediatric and young adult patients.

CONCLUSION

By analyzing a large cohort of pediatric and AYA mesothelioma, this study highlights clinical, prognostic, and survival differences between peritoneal and pleural disease.

LEVEL OF EVIDENCE

Level III.

TYPE OF STUDY

Retrospective.

National Practice Patterns in Malignant Peritoneal Mesothelioma: Updates in Management and Survival

BACKGROUND

Malignant peritoneal mesothelioma (MPM) is a rare malignancy with a historically poor prognosis. Cytoreductive surgery (CRS) with hyperthermic intraperitoneal chemotherapy (HIPEC) has emerged as an effective therapy for patients with peritoneal malignancies. A contemporary analysis of trends in management of and survival from MPM is warranted.

METHODS

Patients with MPM were identified from the National Cancer Database (2004-2018). Patients were categorized by treatment (CRS-HIPEC, CRS-chemotherapy, CRS only, chemotherapy only, no treatment), and joinpoint regression was employed to compute the annual percent change (APC) in treatment over time. Multivariable Cox proportional hazards models were used to analyze factors associated with survival.

RESULTS

Of 2683 patients with MPM, 19.1% underwent CRS-HIPEC, and 21.1% received no treatment. Joinpoint regression revealed a statistically significant increase in the proportion of patients undergoing CRS-HIPEC over time (APC 3.21, p = 0.01), and a concurrent decrease in the proportion of patients who underwent no treatment (APC - 2.21, p = 0.02). Median overall survival was 19.5 months. Factors independently associated with survival included CRS-HIPEC, CRS, histology, sex, age, race, Charlson Comorbidity Index, insurance, and hospital type. Although there was a strong association between year of diagnosis and survival on univariate analysis (2016-2018 HR 0.67, p < 0.001), this association was attenuated after adjustment for treatment.

CONCLUSIONS

CRS-HIPEC is increasingly employed as a treatment for MPM. In parallel, there has been a decrease in patients receiving no treatment with an increase in overall survival. These findings suggest that patients with MPM may be receiving more appropriate therapy; however, a substantial proportion of patients may remain undertreated.

Treatment of Patients with Malignant Peritoneal Mesothelioma

Malignant peritoneal mesothelioma is a rare malignancy arising from the serosa of the peritoneal cavity. It is diagnosed based on suspicious findings on cross sectional imaging and a tissue biopsy showing confirmatory histologic and immunohistochemical features. The disease is hallmarked by its propensity to progress mainly in the peritoneal cavity. In selected patients, surgical cytoreduction and hyperthermic intra-operative peritoneal chemotherapy has become the initial preferred treatment and is associated with provide prolonged in many patients. Systemic chemotherapy using a couplet of cisplatin or gemcitabine with pemetrexed has modest response rates and duration of response. Expression of PD-L1 has been demonstrated in peritoneal mesothelioma tumors and there has been significant interest in the use of check point blockade targeted against PD-L1 in this clinical setting. Future clinical research using a combination of check point blockade with surgical cytoreduction is a high clinical priority.