# Underutilization of CRS, HIPEC & PIPAC in peritoneal mesothelioma across a German nationwide cohort

## TL;DR

This study shows that recommended surgical treatments for peritoneal mesothelioma are rarely used in Germany, despite guidelines.

## Contribution

The study reveals a significant gap between clinical guidelines and actual treatment practices for peritoneal mesothelioma in Germany.

## Key findings

- Only 9% of patients received HIPEC, 15% had peritonectomy, and 5% had PIPAC.
- Most patients were treated at large hospitals, but surgical therapies were underutilized.
- The low use of recommended treatments suggests a need for improved awareness and practice alignment.

## Abstract

This retrospective cohort study utilizes a nationwide database to provide information about the epidemiology and surgical treatment practices of peritoneal mesothelioma in Germany over the years 2019 to 2024.

Data collected by the German Institute for the Hospital Remuneration System (InEK) was examined by age, sex, treatment with HIPEC, PIPAC, or peritonectomy, ICU stay, type of hospital, and duration of stay. Additionally, the Patient Clinical Complexity Level (PCCL) - ranging from 0 to 6 - was analyzed.

In total 3394 patients with peritoneal mesothelioma were recorded during the years 2019 to 2024 in Germany, with an average annual incidence of 0.68 per 100,000 inhabitants. The mean duration of hospital stay was 9 days. The median PCCL was 1. The median patient age group was 65 to 74. 16% of patients had an ICU stay. Most patients were treated at maximum care hospitals with over 1000 beds. Only 9% of patients received HIPEC treatment. 15% received some form of peritonectomy. PIPAC was performed on only 5% of the patients. In total, considering that patients can be coded with multiple procedures, 20% of all patients received surgical therapy.

It was demonstrated that only a small percentage of patients received HIPEC, CRS, or PIPAC. This shows a grave discrepancy between guideline-recommendations and actual clinical practice. Potential reasons could be a lack of consideration of these procedures or misleading economic incentives. Ultimately, the findings highlight the need for increased awareness of peritoneal mesothelioma and underscore the importance to address the aforementioned observed discrepancy.