A23: Contemporary Trends in Malignant Peritoneal Mesothelioma: Incidence and Survival in the United States

Saturday, March 12, 2022

9:11 AM – 9:19 AM CST

Location: Coronado

Abstract Presenter(s)

Lucia M. Calthorpe, MPhil

Medical Student
University of California San Francisco
Berkeley, California, United States

Disclosure: I do not have any relevant financial / non-financial relationships with any proprietary interests.

Participants should be aware of the following financial/non-financial relationships:

Lucia M. Calthorpe, MPhil: I do not have any relevant financial / non-financial relationships with any proprietary interests.

Introduction: Malignant peritoneal mesothelioma (MPM) is a rare disease with a historically poor prognosis. Given the emergence of effective therapies, such as cytoreductive surgery with hyperthermic intraperitoneal chemotherapy, a contemporary analysis of MPM incidence and survival trends is warranted.

Methods: To determine the incidence of MPM from 2000-2018, we analyzed the United States Surveillance, Epidemiology, and End Results 18 registry dataset. Age-adjusted annual incidence was stratified by sex and histology. Joinpoint regression analysis was used to estimate annual percent change (APC) in incidence and evaluate trends over time. Multivariable cox proportional hazards models were used to investigate survival trends.

Results:

From 2000-2018, 1,689 incident cases of MPM were identified. The majority of patients were male (55.4%), older than 50 years (80.0%), and white (75.2%). Epithelioid was the most frequently identified histology (85.0%), followed by biphasic (8.3%), and sarcomatoid (7.2%). The age-adjusted incidence of MPM remained stable over time, with an average annual incidence of 1.08 cases/million. Incidence among females increased by 88.6% over the study period with an APC of 1.2 (95%CI: 0.0, 2.6, p=0.06), and incidence in males increased by 10.5% with an APC of -0.8 (95%CI: -2.2, 0.5). The incidence of epithelioid histology increased by 240% with an APC of 2.5 (95%CI: 0.6, 4.4). Overall median age-standardized survival was 11.6 months. Median age-standardized survival was 16.6 months for those with epithelioid histology, but 2.0 months for those with sarcomatoid histology. From 2000-18, the percent of cases treated with cancer-directed surgery increased from 27% to 43%. In multivariable models, diagnosis in later years and receipt of cancer-directed surgery were associated with improved survival (2015-18 HR: 0.53; 95%CI: 0.42, 0.66, Figure 1).

Conclusions:

Although the overall incidence of MPM has remained stable from 2000-18, there has been a significant increase in the incidence of epithelioid histology. Survival has improved over time, concurrent with an increase in cancer-directed surgery. Future studies are warranted to investigate factors driving improved survival in MPM.

Learning Objectives:

Describe contemporary trends in the incidence of malignant peritoneal mesothelioma in the United States, considering differences by sex and histology
Identify factors associated with improved survival in malignant peritoneal mesothelioma
Recognize the trend of improving survival among patients with malignant peritoneal mesothelioma from 2000-2018