Use of Neoadjuvant Immunotherapy in Malignant Peritoneal Mesothelioma as a Bridge to Surgical Intervention: A Case Report

Our plain-English summary of Use of Neoadjuvant Immunotherapy in Malignant Peritoneal Mesothelioma as a Bridge to Surgical Intervention: A Case Report, by S. Faleh, T. Odisho, F. Lebel-Guay, et al (The American Journal of Case Reports, 2025).

The study

• Authors: S. Faleh, T. Odisho, F. Lebel-Guay, M.L. Soucisse, J. Ferreira, S.V. Soldera, L. Sideris
• Journal: The American Journal of Case Reports
• Published: 2025;26:e949777
• Type of article: Case report
• Read it: PubMed · Publisher · Free full text

Abstract

BACKGROUND Malignant peritoneal mesothelioma (MPM) is a rare subtype of malignant mesothelioma (MM) that arises from mesothelial/serosal surfaces of the peritoneal lining and carries a poor prognosis. Given the rarity of this disease, many expert groups such as the Peritoneal Surface Oncology Group International (PSOGI) and the National Comprehensive Cancer Network (NCCN) have developed recommendations to guide the optimal treatment for MPM. Currently, the standard of care for resectable MPM is a combination of cytoreductive surgery (CRS) followed by hyperthermic intraperitoneal chemotherapy (HIPEC). There are no clear guidelines for treatment of inoperable malignant mesothelioma, but several studies have demonstrated a benefit of incorporating immunotherapy in the treatment plan. CASE REPORT We present a case of a 63-year-old woman who sought medical attention for several months of persistent vague abdominal discomfort, weight loss, and night sweats. Laboratory workup and diagnostic imaging led to the diagnosis of borderline/unresectable MPM. A multidisciplinary tumor board discussion based on the published literature and guidelines on malignant mesothelioma (MM) was undertaken, and the decision was made to treat the patient with nivolumab-ipilimumab in the perioperative period. The patient had a positive clinical response allowing for subsequent CRS and HIPEC. She remains disease free 30 months following her surgery, with the intention to continue the immunotherapy. CONCLUSIONS This case report contributes to the current literature demonstrating a potential role for perioperative immunotherapy in the treatment of aggressive subtype or borderline resectable/unresectable MPM and a bridge to consolidative CRS/HIPEC.

In plain English

This case report described one patient: a 63-year-old woman, a non-smoker with no history of asbestos exposure. She had vague abdominal discomfort lasting a year, along with weight loss, fatigue, shortness of breath on exertion and night sweats. She was diagnosed with malignant peritoneal mesothelioma, a cancer of the abdominal lining, of the epithelial subtype, and her disease was considered borderline resectable or unresectable. Before surgery she received two immunotherapy drugs, nivolumab and ipilimumab. After 4 months her symptoms had resolved, scans showed a partial response, and side effects were grade 1 to 2 only. She then had cytoreductive surgery with complete cytoreduction (a score of 0), followed by heated chemotherapy inside the abdomen (HIPEC), and immunotherapy continued afterward. Imaging in July 2024 showed no recurrence. The article stated she remained disease free 30 months after surgery, although its follow-up section described 18 months of follow-up. The authors concluded that immunotherapy may make surgery possible for more patients by shrinking tumors that were at first unresectable. A case report describes one person's course, not how often an outcome occurs.

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 of a single patient
• Who was studied: One 63-year-old female non-smoker with type-2 diabetes mellitus and other medical conditions, who was diagnosed with malignant peritoneal mesothelioma
• Exposure: The patient had no history of asbestos exposure. The treatment described was nivolumab and ipilimumab given before and after cytoreductive surgery and HIPEC.
• Main results:
  • The patient had vague abdominal discomfort lasting a year. She also reported significant weight loss, fatigue, shortness of breath on exertion, night sweats and changes in bowel habits. The article gives no duration for these other symptoms.
  • Pathology showed malignant peritoneal mesothelioma of the diffuse epithelial subtype
  • Treatment before surgery was nivolumab 3 mg/kg intravenously every 2 weeks and ipilimumab 1 mg/kg intravenously every 6 weeks
  • After 4 months of immunotherapy, all disease-related symptoms resolved, and toxicity was grade 1 to 2 only
  • Restaging scans showed a partial response and no metastases outside the abdomen
  • Surgery achieved a complete cytoreduction index of 0, followed by HIPEC
  • The final peritoneal cancer index at surgery was 25
  • The patient was discharged on postoperative day 15
  • Final pathology showed epithelioid-type malignant peritoneal mesothelioma with Ki-67 of 5%
  • Nivolumab and ipilimumab were continued after surgery, with a plan to continue for up to 2 years
  • The patient was followed for a total of 18 months at 3-month intervals. Imaging in July 2024 showed no recurrence.
  • The article states the patient remained disease free 30 months after surgery
• The authors' conclusion: The authors concluded that their case suggests immunotherapy may expand the population who can have surgery by downstaging tumors that were initially unresectable

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: Immunotherapy, Peritoneal Mesothelioma, Mesothelioma, Serosal Surface, Prognosis, Peritoneal Surface Oncology, Cytoreductive Surgery, HIPEC.

Related studies

• Neoadjuvant Pressurized Intraperitoneal Aerosol Chemotherapy for Conversion to Cytoreductive Surgery in Unresectable Malignant Peritoneal Mesothelioma: A Report of 2 Cases — A. Urbano-Ruiz, B. Latronico Palma, et al. (2026)
• Building a Bridge between Chemotherapy and Immunotherapy in Malignant Pleural Mesothelioma: Investigating the Effect of Chemotherapy on Immune Checkpoint Expression — E. Marcq, J.R.V. Audenaerde, et al. (2019)
• The next generation of immunotherapy: keeping lung cancer in check — A. Somasundaram, T.F. Burns (2017)
• Malignant mesothelioma clinical trial combines immunotherapy drugs — M.S. Chatwal, T. Tanvetyanon (2018)
• Complete pathological response to neoadjuvant pemetrexed/cisplatin in combination with regional hyperthermia in a patient with sarcomatoid peritoneal mesothelioma — S. Kruger, M.K. Angele, et al. (2014)
• Adjuvant dendritic cell-based immunotherapy after cytoreductive surgery and hyperthermic intraperitoneal chemotherapy in patients with malignant peritoneal mesothelioma: a phase II clinical trial — M.V. Dietz, K.L.A. Quintelier, et al. (2023)

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