Neoadjuvant Pressurized Intraperitoneal Aerosol Chemotherapy for Conversion to Cytoreductive Surgery in Unresectable Malignant Peritoneal Mesothelioma: A Report of 2 Cases

Our plain-English summary of Neoadjuvant Pressurized Intraperitoneal Aerosol Chemotherapy for Conversion to Cytoreductive Surgery in Unresectable Malignant Peritoneal Mesothelioma: A Report of 2 Cases, by A. Urbano-Ruiz, B. Latronico Palma, R.E. Carnut Rego, et al (The American Journal of Case Reports, 2026).

The study

• Authors: A. Urbano-Ruiz, B. Latronico Palma, R.E. Carnut Rego, D. Bianqui Guaraldo da Silva, B. Fava, E. Araujo Falcão, M.L. Rodrigues Barbosa da Silva, J. Rodrigues Leandro Uliano
• Journal: The American Journal of Case Reports
• Published: 2026;27:e950407
• Type of article: Case report
• Read it: PubMed · Publisher · Free full text

Abstract

BACKGROUND Peritoneal mesothelioma (PM) is the second most common presentation site of malignant mesothelioma. The standard of care for PM is cytoreductive surgery (CRS) combined with hyperthermic intraperitoneal chemotherapy (HIPEC). Because of its insidious manifestations, PM is often diagnosed at advanced, unresectable stages, precluding optimal cytoreduction and diminishing long-term survivability. CASE REPORT We report 2 cases of advanced and unresectable PM (stages III and IV) presenting with symptomatic with low-grade epithelioid disease. Both cases had a high peritoneal cancer index (PCI >30) and extensive small-bowel involvement. The patients underwent pressurized intraperitoneal aerosol chemotherapy (PIPAC) with cisplatin and doxorubicin as downstaging conversion therapy. Patient 1 was a 47-year-old man with a laparoscopic PCI of 34 and progression of disease despite 5 months of systemic intravenous chemotherapy. After 2 cycles of PIPAC, the patient showed disease regression and complete resolution of large ascites; CRS-HIPEC was feasible with complete cytoreduction (CC-0). The patient was discharged after a 60-day hospital stay. Patient 2 was a 43-year-old man with a laparoscopic PCI of 30 and no prior lines of therapy. After a single PIPAC cycle, there was clear disease regression (PCI=23), allowing CRS-HIPEC with optimal cytoreduction (CC-1). The patient was discharged after 10 days. CONCLUSIONS PIPAC is established as a suitable option for palliation of massive ascites in PM; however, in selected candidates with favorable prognostic biomarkers and appropriate fitness for surgery, the procedure can serve as a bridge to definitive open surgery (CRS-HIPEC) aimed at achieving complete cytoreduction.

In plain English

This article reported two cases of malignant peritoneal mesothelioma, a cancer of the abdominal lining. Both patients were treated in 2023 at a specialized center in Brazil. They were men aged 47 and 43 with low-grade epithelioid disease that was too widespread to remove, with extensive small-bowel involvement. The article did not discuss asbestos. For Patient 1 it stated no relevant occupational history. Both received pressurized intraperitoneal aerosol chemotherapy (PIPAC), in which cisplatin and doxorubicin were sprayed into the abdomen. Patient 1's disease had progressed during a 5-month course of pemetrexed. After PIPAC, this patient's abdominal fluid disappeared and surgery with heated chemotherapy (CRS-HIPEC) removed all visible tumor (CC-0). Complications followed, and the patient left hospital on day 60. In Patient 2, the disease score fell from 30 to 23 during PIPAC. Surgery left only small remnants (CC-1), and the patient left hospital after 10 days. Neither patient showed recurrence on scans at 3 and 6 months. The authors concluded that, in selected patients, PIPAC can serve as a bridge to surgery aimed at complete tumor removal.

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: Case report (case series) of two patients
• Who was studied: Two men, aged 47 (from Goiânia) and 43 (from São Paulo), with advanced, unresectable low-grade epithelioid malignant peritoneal mesothelioma; treated in 2023 at the Center for Peritoneal Diseases, Hospital Beneficência Portuguesa de São Paulo, Brazil
• Exposure: The article studies a treatment, not asbestos exposure. The treatment was PIPAC with cisplatin 10.5 mg/m2 and doxorubicin 2.1 mg/m2, followed by cytoreductive surgery with hyperthermic intraperitoneal chemotherapy (CRS-HIPEC). Asbestos is not mentioned.
• Main results:
  • Patient 1 had no relevant occupational history.
  • Patient 1 had received a 5-month course of systemic pemetrexed before referral, with signs of disease progression.
  • Patient 1 had a laparoscopic PCI of 34 (stage IV) at the first PIPAC. Ascites, 3900 mL at the first procedure, decreased and was absent at the last instillation.
  • Patient 1 achieved complete cytoreduction (CC-0) at CRS-HIPEC.
  • Patient 1 had postoperative complications classified as Clavien-Dindo IIIa that did not require reoperation, and was discharged on postoperative day 60.
  • Patient 2 had a laparoscopic PCI of 30 at the first instillation, which fell to 27 and then 23 over the following two sessions. The surgical PCI was 28.
  • Patient 2's CRS-HIPEC left tumor remnants in the mesentery, giving a completeness score of CC-1.
  • Patient 2 was discharged after 10 days.
  • Patient 1: CT scans at 3 and 6 months after discharge showed no remnant disease or recurrence.
  • Patient 2: CT scans at 3 and 6 months after surgery showed no abnormalities.
• The authors' conclusion: The authors concluded that PIPAC is established for palliating massive ascites in peritoneal mesothelioma. They added that, in selected candidates with favorable prognostic biomarkers and fitness for surgery, it can serve as a bridge to CRS-HIPEC aimed at complete cytoreduction.
• Limitations the authors state:
  • Surgical specimens from both patients still showed microscopic low-grade disease in all samples. The authors noted this may not match the visible regression seen during PIPAC.
  • Peritoneal biopsies were not repeated to assess the Peritoneal Regression Score.
  • The authors stated that more data and larger patient populations are needed to analyze ascites volume as a factor linked to treatment response.

Topics

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

Medical terms in this study, explained in our Lexicon: Chemotherapy, Cytoreductive Surgery, Unresectable, Peritoneal Mesothelioma, Mesothelioma, HIPEC, Epithelioid, Peritoneal Cancer Index (PCI).

Related studies

• 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)
• Laparoscopic cytoreductive surgery and hyperthermic intraperitoneal chemotherapy for limited peritoneal metastasis. The PSOGI international collaborative registry — A. Arjona-Sanchez, O. Aziz, et al. (2021)
• Conversion to Complete Cytoreductive Surgery and Hyperthermic Intraperitoneal Chemotherapy for Malignant Peritoneal Mesothelioma After Bidirectional Chemotherapy — F. Le Roy, M. Gelli, et al. (2017)
• The results of cytoreductive surgery and hyperthermic intraperitoneal chemotherapy in 1200 patients with peritoneal malignancy — B. Moran, T. Cecil, et al. (2015)
• Iterative procedures combining cytoreductive surgery and hyperthermic intraperitoneal chemotherapy for isolated peritoneal recurrence — M. Vaira, M. Robella, et al. (2014)
• The role of cytoreductive surgery and hyperthermic intraperitoneal chemotherapy in the treatment of peritoneal carcinomatosis: a systematic review including evidence from Japan — T. Kitai (2021)

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