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

Our plain-English summary of Underutilization of CRS, HIPEC & PIPAC in peritoneal mesothelioma across a German nationwide cohort, by V. Müller, M. Hornung, J. Werner, et al (World Journal of Surgical Oncology, 2026).

The study

• Authors: V. Müller, M. Hornung, J. Werner, H.J. Schlitt, M. Acs
• Journal: World Journal of Surgical Oncology
• Published: 2026;24(1)
• Read it: PubMed · Publisher · Free full text

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.

In plain English

This study looked back at German national hospital billing records from InEK, the institute that runs the hospital payment system. It covered people coded with peritoneal mesothelioma, a cancer of the lining of the abdomen, from 2019 to 2024. The records held 3394 cases, an average yearly incidence of 0.68 per 100,000 inhabitants. Incidence fell significantly, with an annual percent change of -5% (confidence interval -9% to -2%). HIPEC (heated chemotherapy delivered into the abdomen) was recorded for 318 patients (9%). PIPAC (pressurized aerosol chemotherapy in the abdomen) was recorded for 156 (5%). Peritonectomy, which the authors used as the marker for cytoreductive surgery, was recorded for 510 (15%). In total, 20% received some surgical therapy. The study collected no asbestos exposure data. The authors suggested Germany's asbestos ban as one possible explanation for the decline. They concluded there was a grave discrepancy between guideline recommendations and actual treatment. They noted that procedures coded differently would have been missed, that the codes do not separate tumor subtypes, and that 2024 data may be incomplete.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Retrospective cohort study: descriptive analysis of a nationwide German hospital remuneration (billing) database, with Joinpoint regression to test for a trend in incidence
• Who was studied: 3394 cases of peritoneal mesothelioma (ICD-10 code C45.1) recorded in German hospital data (InEK) from 2019 to 2024
• Exposure: The study did not collect asbestos or other exposure data. It examined recorded treatments (HIPEC, PIPAC, peritonectomy) by procedure code. Asbestos appears only in the discussion, where the authors offer Germany's asbestos ban as a possible explanation for the falling incidence.
• Main results:
  • Average annual incidence was 0.68 per 100,000 inhabitants. Incidence decreased significantly over 2019 to 2024, with an annual percent change of -5% (p-value 0.0032; CI -9% to -2%).
  • HIPEC was recorded for 318 patients, 9% of all patients with peritoneal mesothelioma.
  • PIPAC was recorded for 156 patients (5%). An operation including peritonectomy was recorded for 510 patients (15%).
  • Allowing for patients coded with more than one procedure, 20% of all patients received surgical therapy.
  • For 246 patients, peritonectomy was recorded without HIPEC.
  • Across all patients, the mean hospital stay was 9 days, with a standard deviation of 11.
  • 16% of all patients with peritoneal mesothelioma had an ICU stay.
  • 94% of patients receiving HIPEC and 65% of patients receiving peritonectomy had an ICU stay. No ICU stays were recorded after PIPAC.
  • HIPEC was not recorded in any hospital with fewer than 600 beds.
  • A mean of 58% of all patients with peritoneal mesothelioma were male.
• The authors' conclusion: The authors concluded that their data show a grave discrepancy between guideline recommendations and the actual treatment of patients with peritoneal mesothelioma in Germany, and that further research is needed into the reasons.
• Limitations the authors state:
  • Only data carrying the chosen ICD-10 and procedure codes could be identified, so procedures or diagnoses coded differently were missed.
  • The specific procedure code for PIPAC was introduced in 2019 and may not have been familiar to some centers in the early years.
  • Codes for systemic chemotherapy were not analyzed.
  • The diagnostic code does not distinguish histological subtypes, so a high number of sarcomatoid cases (not eligible for surgery) could have affected the results.
  • Data for 2024 may be incomplete because reports for that year had not yet fully accumulated.

Topics

The National Library of Medicine indexes this study under subjects our site covers: Mesothelioma, Peritoneal mesothelioma.

Medical terms in this study, explained in our Lexicon: HIPEC, Peritoneal Mesothelioma, Cohort Study, Epidemiology.

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• Unresectable peritoneal metastasis treated by pressurized intraperitoneal aerosol chemotherapy (PIPAC) leading to cytoreductive surgery and hyperthermic intraperitoneal chemotherapy — M. Alyami, F. Mercier, et al. (2021)
• FASN for diffuse malignant peritoneal mesothelioma: a prognostic biomarker after CRS+HIPEC and a therapeutic target — V. Doldi, C.M. Ciniselli, et al. (2026)
• Long-term results of laparoscopic cytoreductive surgery and HIPEC for the curative treatment of low-grade pseudomyxoma peritonei and multicystic mesothelioma — F. Mercier, G. Jeremie, et al. (2020)
• The Safety of Iterative Cytoreductive Surgery and HIPEC for Peritoneal Carcinomatosis: A High Volume Center Prospectively Maintained Database Analysis — E. Bekhor, J. Carr, et al. (2020)
• National Guidelines for Cytoreductive Surgery and Hyperthermic Intraperitoneal Chemotherapy (HIPEC) in Peritoneal Malignancies: A Worldwide Systematic Review and Recommendations of Strength Analysis — M. Tonello, C. Cenzi, et al. (2025)

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