Long-Term Survival of More than 5 Years with Maintenance Therapy Using Single-Agent Pemetrexed in a Patient with Diffuse Malignant Peritoneal Mesothelioma

Our plain-English summary of Long-Term Survival of More than 5 Years with Maintenance Therapy Using Single-Agent Pemetrexed in a Patient with Diffuse Malignant Peritoneal Mesothelioma, by Y. Otsuka, Y. Komeda, M. Takeda, et al (Case Reports in Medicine, 2023).

The study

• Authors: Y. Otsuka, Y. Komeda, M. Takeda, T. Takahama, M. Kono, M. Takenaka, S. Hagiwara, N. Nishida, H. Kashida, M. Kudo
• Journal: Case Reports in Medicine
• Published: 2023;2023:2092157
• Type of article: Case report
• Read it: PubMed · Publisher · Free full text

Abstract

A 76-year-old woman presented with lower abdominal pain and nausea and was referred to the gastroenterology department in our institution. Previous contrast-enhanced computed tomography (CE-CT) for follow-up after breast cancer surgery had indicated a soft tissue mass below the right diaphragm, which was considered a benign change. CE-CT performed at the first visit to our department revealed further thickening of the soft tissue mass with extension to the liver surface. In addition, ascites and nodules were observed in the abdominal cavity. Histopathological examination of a biopsy specimen revealed peritoneal invasion of atypical epithelioid cells with trabecular and glandular patterns. The tumor cells were positive for AE1/AE2, calretinin, WT-1, D2-40, HEG1, EMA, BAP1, and MTAP and negative for carcinoembryonic antigen, MOC-31, Ber-Ep4, ER, PgR, TTF-1, claudin 4, and desmin. A diagnosis of epithelioid mesothelioma was made. The patient received chemotherapy with cisplatin (75 mg/m2) and pemetrexed (500 mg/m2). After six courses of combined chemotherapy, pemetrexed was administered as a single agent. At the time of writing this report, she was undergoing over the 30th course of chemotherapy without any significant side effects. Diffuse malignant peritoneal mesothelioma is a rare, fatal, and progressive disease. Our patient achieved long-term survival of more than 5 years with maintenance therapy using single-agent pemetrexed.

Copyright © 2023 Yasuo Otsuka et al.

In plain English

This case report described one patient, a 76-year-old woman in Japan under follow-up after breast cancer surgery, who developed lower abdominal pain and nausea. Her medical history did not include any apparent episodes of asbestos exposure. Scans showed a growing soft tissue mass below the right diaphragm, abdominal fluid and nodules. A biopsy led to a diagnosis of epithelioid mesothelioma, which the authors described as diffuse malignant peritoneal mesothelioma. Because spread within the abdomen was suspected, surgery was considered difficult, and she received chemotherapy with cisplatin and pemetrexed. After six courses, cisplatin was stopped once the total dose exceeded 500 mg. In the discussion, the authors wrote that irreversible side effects such as peripheral neuropathy and renal failure occurred at that point. She then continued on pemetrexed alone. A scan 48 months after chemotherapy began showed stable disease. At the time of writing she had survived more than 5 years and was beyond her 30th course without significant side effects. The authors considered that the long-term treatment led to prolonged survival. They noted that they reported only one case and that a clinical trial is 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 (a single patient)
• Who was studied: One 76-year-old woman under follow-up after breast cancer surgery, seen at Kindai University Hospital, Japan, with lower abdominal pain and nausea
• Exposure: No apparent asbestos exposure was recorded in her medical history; no fiber type or job exposure was reported
• Main results:
  • The biopsy led to a diagnosis of epithelioid mesothelioma, described as diffuse malignant peritoneal mesothelioma
  • Because scans suggested spread through the peritoneum, surgery was considered difficult and chemotherapy was given instead
  • A CT scan 12 months after the start of treatment showed no change in the tumor
  • After six courses of cisplatin (75 mg/m2) plus pemetrexed (500 mg/m2), she was switched to pemetrexed alone because the total cisplatin dose exceeded 500 mg
  • In the discussion, the authors stated that irreversible side effects such as peripheral neuropathy and renal failure occurred when the total cisplatin dose exceeded 500 mg
  • A CT scan 48 months after the start of chemotherapy showed stable disease, and her abdominal symptoms had improved
  • At the time of writing, she was undergoing more than her 30th course of chemotherapy without significant side effects
  • The patient survived more than 5 years with single-agent pemetrexed maintenance therapy
• The authors' conclusion: The authors considered that the long-term effect of the treatment led to this patient's prolonged survival. They said the usefulness of pemetrexed maintenance therapy should be examined in a clinical trial.
• Limitations the authors state:
  • Only one case was reported, so the authors said the usefulness of pemetrexed maintenance therapy should be tested in a clinical trial
  • Biomarkers linked to sensitivity to pemetrexed were not examined in this patient
  • Gene therapy could not be explored because the biopsy did not provide enough tissue

Topics

Medical terms in this study, explained in our Lexicon: Pemetrexed (Alimta), Peritoneal Mesothelioma, Diaphragm, Ascites, Biopsy, Epithelioid, Trabecular, Calretinin.

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