Pembrolizumab as an effective treatment for diffuse malignant peritoneal mesothelioma with long‑term survival: A case report and literature review

Our plain-English summary of Pembrolizumab as an effective treatment for diffuse malignant peritoneal mesothelioma with long‑term survival: A case report and literature review, by C. Xue, Z. Dong, K. Tan, et al (Oncology Letters, 2025).

The study

• Authors: C. Xue, Z. Dong, K. Tan, X. Zhang, Y. Yu, S. Wang, J. Zheng, H. Cui
• Journal: Oncology Letters
• Published: 2025;29(4):187
• Type of article: Case report
• Cited by: 1 article, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Primary diffuse malignant peritoneal mesothelioma (MPEM) is a malignant disease without standard treatments recommended. Recently, immunotherapy has revolutionized the field of tumor therapy. According to current clinical evidence, advanced MPEM may gain potential clinical benefits from immune checkpoint inhibitors. The present study reported a 61-year-old female patient with persistent low fever as the initial symptom, who was eventually diagnosed with MPEM. This patient obtained significant clinical benefits from pembrolizumab, with disappearance of symptoms, a lasting stable disease response with a progression-free survival of 10.0 months and a long overall survival of 26.2 months. The application of pembrolizumab was explored as an emerging effective treatment for patients with MPEM. In addition, the clinical characteristics, diagnosis, treatment, pathogenesis and target regulation in MPEM were discussed and previous studies were reviewed. Further evidence is needed from future extensive clinical trials.

Copyright: © 2025 Xue et al.

In plain English

This article was a case report with a literature review. It described a previously healthy 61-year-old Chinese woman who, from February 2021, had a long-lasting low fever and later an abdominal mass. She had no known exposure to asbestos. A biopsy led to a diagnosis of diffuse epithelial malignant peritoneal mesothelioma at stage III. Surgery was not recommended, she declined chemotherapy, and she could not afford a two-drug immunotherapy combination. From June 2021 she received the immunotherapy drug pembrolizumab alone as her first treatment. Her fever resolved after the first cycle. Up to February 2022 she had no adverse events and her disease stayed stable. The authors reported a progression-free survival of 10.0 months on pembrolizumab. Later, pemetrexed brought no benefit. Albumin-bound paclitaxel plus pembrolizumab relieved symptoms and slightly shrank the tumor but caused intolerable side effects, as did anlotinib plus pembrolizumab. She stopped treatment for financial reasons and died in July 2023, an overall survival of 26.2 months. The authors also reviewed published immunotherapy reports for this cancer. The authors concluded pembrolizumab may be effective and well tolerated, but larger trials are needed.

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 one patient, with a literature review of PubMed studies on immunotherapy for malignant peritoneal mesothelioma (search updated until July 2024) and of published cases of fever and blood-related paraneoplastic syndromes in this disease
• Who was studied: One previously healthy 61-year-old Chinese woman treated at the China-Japan Friendship Hospital, Beijing, with symptoms from February 2021; diagnosed with diffuse epithelial malignant peritoneal mesothelioma, stage III (T4N0M0), peritoneal cancer index 33
• Exposure: The exposure studied was treatment with pembrolizumab, given alone as first-line therapy: 100 mg every 21 days for the first cycle, then 200 mg every 21 days for cycles 2 to 12 (June 2021 to February 2022). The patient had no known asbestos exposure.
• Main results:
  • The patient's fever resolved completely after the first cycle of pembrolizumab
  • During pembrolizumab treatment up to February 2022, the patient had stable disease, no adverse events or new symptoms, and the pelvic masses shrank on imaging
  • In February 2022 the upper abdominal target lesion was slightly enlarged but the disease was still stable, and one month later the pelvic lesions had shrunk; overall the patient had stable disease on pembrolizumab, with progression-free survival of 10.0 months
  • Two cycles of pemetrexed given afterwards brought no clinical or imaging benefit
  • Third-line albumin-bound paclitaxel plus pembrolizumab (four cycles) gave symptom remission and slight shrinkage on imaging, but the patient could not tolerate bone marrow suppression and lasting abdominal distension
  • Fourth-line anlotinib plus pembrolizumab caused severe adverse events the patient could not tolerate, and the abdominal mass increased slightly after one cycle
  • The patient refused further treatment for financial reasons, died in July 2023, and had an overall survival of 26.2 months
  • The tumor tested positive for PD-L1 (22C3) with a CPS of 60%, and Ki-67 was above 30%
• The authors' conclusion: The authors concluded that pembrolizumab may be an effective and well-tolerated treatment for malignant peritoneal mesothelioma, and that more evidence from larger clinical trials is needed
• Limitations the authors state:
  • The authors noted that individual factors cannot be ignored
  • The authors stated that the best treatment requires verification in more clinical cases and in large multicenter randomized trials

Topics

Medical terms in this study, explained in our Lexicon: Pembrolizumab (Keytruda), Peritoneal Mesothelioma, Immunotherapy, checkpoint inhibitors, Progression-Free Survival, Overall Survival, Clinical Trial.

Related studies

• Long-Term Survival of More than 5 Years with Maintenance Therapy Using Single-Agent Pemetrexed in a Patient with Diffuse Malignant Peritoneal Mesothelioma — Y. Otsuka, Y. Komeda, et al. (2023)
• Treatment factors associated with long-term survival after cytoreductive surgery and regional chemotherapy for patients with malignant peritoneal mesothelioma — H.R. Alexander, D.L. Bartlett, et al. (2013)
• Long-term survival of a woman with well differentiated papillary mesothelioma of the peritoneum: a case report and review of the literature — J.M. Clarke, P. Helft (2010)
• Small bowel metastasis from pancreatic cancer in a long-term survival patient with synchronous advanced malignant pleural mesothelioma: A case report and literature review — M. Fasano, C.M. Della Corte, et al. (2016)
• Long-term survival of nonoccupational pleural mesothelioma: a case report and review of the literature — L. Tobia, E. Tolli, et al. (2025)
• Long-term survival from multidisciplinary treatment of primary malignant pericardial mesothelioma: A case report — V.A. Hai, N.T.M. Chau, et al. (2024)

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