Navigating the Foggy Landscape of Epithelioid Peritoneal Mesothelioma: A Proposed Standardized Institutional Algorithm for Multimodal Management

Our plain-English summary of Navigating the Foggy Landscape of Epithelioid Peritoneal Mesothelioma: A Proposed Standardized Institutional Algorithm for Multimodal Management, by G. D'Annibale, F. Santullo, L. Barberis, et al (Cancers, 2026).

The study

• Authors: G. D'Annibale, F. Santullo, L. Barberis, C. Lodoli, T. Partipilo, G.G. La Manna, A. Strippoli, A. Spring, F. Pacelli, C. Abatini
• Journal: Cancers
• Published: 2026;18(13)
• Read it: PubMed · Publisher · Free full text

Abstract

Purpose: Diffuse malignant peritoneal mesothelioma is a rare disease requiring management in specialized referral centers. We report our institutional experience with epithelioid diffuse malignant peritoneal mesothelioma, focusing on a standardized treatment algorithm and on pre-operative cisplatin-pemetrexed as a bridge to cytoreductive surgery and HIPEC. Methods: Consecutive patients treated between 2016 and 2024 were retrospectively reviewed. Treatment allocation was based on diagnostic laparoscopy, PCI assessment, and multidisciplinary evaluation. Patients with technically resectable disease underwent upfront CRS-HIPEC, whereas borderline or unresectable patients received cisplatin-pemetrexed followed by systematic reassessment. Results: Forty-three patients were included; 19 underwent CRS-HIPEC, including 8 after pre-operative chemotherapy, and 24 received medical management alone. Curative-intent cytoreduction (CC-0/1) was achieved in all operated patients, with no 30-day mortality. No statistically significant difference in overall survival was detected between upfront and conversion surgery patients in this small cohort. Higher PCI and Ki-67 were independently associated with worse overall survival. Conclusions: A structured multidisciplinary pathway may support tailored treatment selection in epithelioid diffuse malignant peritoneal mesothelioma. In selected responders, cisplatin-pemetrexed may act as a bridge to surgery, although larger studies are required to validate this strategy.

In plain English

This retrospective study from one referral center in Rome, Italy, covered 43 patients with epithelioid diffuse malignant peritoneal mesothelioma treated from 2016 to 2024. It studied treatment, not asbestos exposure. Patients fit for surgery whose tumors were judged removable had surgery plus heated chemotherapy inside the abdomen (CRS-HIPEC) first. Others well enough for chemotherapy received cisplatin–pemetrexed and were reassessed; those too unwell for either received symptom-focused care. Nineteen patients had surgery (11 upfront, 8 after chemotherapy) and 24 had medical treatment only. All 19 operated patients had complete or near-complete tumor removal. Eleven had post-operative complications; none died within 30 days. Among operated patients, median overall survival from diagnosis was 50 months in both the upfront and after-chemotherapy groups, with no statistically significant difference. In the surgical group, a higher Peritoneal Cancer Index (extent of disease spread) and higher Ki-67 (tumor cell growth rate) were associated with worse survival. The authors concluded that chemotherapy may help selected patients become candidates for surgery. The authors noted the study was small, retrospective and single-center, and called for larger studies.

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 single-center cohort study describing an institutional treatment algorithm
• Who was studied: 43 patients with histologically confirmed epithelioid diffuse malignant peritoneal mesothelioma, treated January 2016 to December 2024 at a peritoneal surgery unit in Rome, Italy. Sarcomatoid or biphasic histology and recurrent disease were excluded.
• Exposure: No asbestos exposure was studied or reported. The study examined treatments: cytoreductive surgery with HIPEC (cisplatin and doxorubicin) for patients with technically achievable cytoreduction who were fit for surgery, and first-line cisplatin–pemetrexed for patients not suitable for upfront surgery who had acceptable performance status (0 to 2). PIPAC was a palliative option. Patients with poor performance status received life-prolonging treatment focused on symptom relief.
• Main results:
  • 19 of 43 patients (44.2%) underwent CRS-HIPEC and 24 (55.8%) had medical management only. Of the 19 surgical patients, 11 (57.9%) had upfront surgery and 8 (42.1%) had surgery after pre-operative cisplatin–pemetrexed.
  • Among the 19 surgical patients, complete cytoreduction (CC-0) was achieved in 11 (57.9%) and near-complete cytoreduction (CC-1) in 8 (42.1%), so all 19 had curative-intent cytoreduction.
  • Post-operative complications occurred in 11 of 19 surgical patients (57.9%). Major complications (Clavien–Dindo grade III or higher) occurred in 5 (26.3%).
  • No patient in the surgical group died within 30 days.
  • In the surgical group, median overall survival (measured from diagnosis) was 50 months (range 4 to 75). Median disease-free survival (measured from CRS-HIPEC) was 12 (range 2 to 43).
  • Median overall survival was 50 months in both the upfront surgery group and the conversion surgery group. The difference was not statistically significant (log-rank p = 0.125) in this small cohort.
  • In the surgical group's multivariate analysis, a higher PCI score was associated with worse overall survival: HR 1.195, 95% CI 1.038 to 1.375, p = 0.013.
  • In the same multivariate analysis, a higher Ki-67 proliferative index was associated with worse overall survival: HR 1.169, 95% CI 1.030 to 1.382, p = 0.019.
  • In the surgical group, pre-operative chemotherapy was not significantly associated with survival (univariate HR 1.021, 95% CI 0.252 to 4.131, p = 0.977). Intra-operative and post-operative complications were also not significantly associated with survival.
  • The authors reported that 25% (8/32) of patients who received chemotherapy responded enough to be converted to resectable disease and underwent CRS-HIPEC.
  • In the medical-management group, median overall survival was listed as 7 (range 1 to 49). The authors reported this for descriptive purposes only and said it reflects older, frailer patients with unresectable disease, not the effect of medical treatment alone.
• The authors' conclusion: The authors concluded that, within their standardized pathway, CRS-HIPEC achieved favorable long-term survival, including in patients converted to surgery after cisplatin–pemetrexed. They said this supports a surgery-centered strategy in which chemotherapy may help a selected subset of patients become resectable, and that larger multicenter studies are needed to validate the algorithm.
• Limitations the authors state:
  • The analysis was retrospective and based on a single center.
  • The small sample size may limit statistical power and generalizability.
  • Because there were few events, the multivariable analyses are exploratory.
  • The upfront and conversion surgery subgroups were small, so their comparison should be interpreted with caution.
  • Residual confounding and selection bias cannot be excluded.
  • The surgical and medical-management groups were not meant to be compared as equivalent cohorts. Medical-management data are descriptive only.
  • Referral-center selection bias is possible: the center may have attracted patients with better performance status or greater suitability for aggressive therapy.

Topics

Medical terms in this study, explained in our Lexicon: Epithelioid, Peritoneal Mesothelioma, Cisplatin, Pemetrexed (Alimta), Cytoreductive Surgery, HIPEC, Diagnostic Laparoscopy, Unresectable.

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