Peritoneal mesothelioma proposal for a staging system

Our plain-English summary of Peritoneal mesothelioma proposal for a staging system, by G. Sebbag, P.H. Sugarbaker (European Journal of Surgical Oncology, 2001).

The study

• Authors: G. Sebbag, P.H. Sugarbaker
• Journal: European Journal of Surgical Oncology
• Published: 2001;27(3):223-4
• Type of article: Editorial
• Cited by: 25 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Summary of the article

This editorial proposed a staging system for peritoneal mesothelioma. The authors noted that mesothelioma incidence was expected to peak around 2020 in industrialized nations, mainly because of high asbestos exposure after the Second World War. They stated that peritoneal mesothelioma affects a younger population than the pleural form and has a more tenuous link to asbestos (15–30% vs 60–70%) and smoking. They also noted that no staging classification existed for the peritoneal form. Forty patients with peritoneal mesothelioma had been referred to their Washington institution over 12 years. The authors based the proposal on 33 patients they had previously reported, who were treated with cytoreductive surgery and perioperative intraperitoneal chemotherapy (median survival 31.0 months). Variables predictive of survival included completeness of cytoreduction (P=0.0002), metastasis (P=0.001), prior surgical score (P=0.002), female gender (P=0.003), second-look surgery (P=0.019) and a Peritoneal Cancer Index (PCI) below 28 (P=0.025). Metastasis and PCI, both independent of treatment, were retained. Histological subtype did not significantly affect survival, but three grades (G1–G3) were defined. In the resulting TGM system, median survival was 52.0 months for stage I, 32.5 months for stage II, 15.5 months for stage III and 13.5 months for stage IV. Estimated 3-year survival was 90–100%, 60–70%, 30–40% and below 20%. The authors also noted a pelvic origin in their early cases and raised the question of a pelvic field defect.

PubMed has no abstract for this study, and the article doesn't print one. We wrote this summary from the full article with the help of AI. It is not the authors' wording.

In plain English

This two-page editorial, by surgeons at the Washington Cancer Institute, proposed a staging system for peritoneal mesothelioma, which is mesothelioma of the lining of the abdomen. It did not study asbestos exposure. The proposal drew on 33 patients with peritoneal mesothelioma whom the authors had reported in an earlier paper. In those patients several factors were significantly linked to survival. Two that did not depend on treatment were kept for the system: distant metastasis, and the Peritoneal Cancer Index, a score from 0 to 39 that measures how much tumour is spread across regions of the abdomen. Patients with an index below 28 had significantly better survival (P=0.025). Survival did not differ significantly by pathological subtype, but the authors grouped the subtypes into three grades. The resulting 'TGM' system (tumour extent, grade, metastasis) has four stages. When the 33 patients were classified by stage, median survival was 52.0 months in stage I, 32.5 months in stage II, 15.5 months in stage III and 13.5 months in stage IV. The authors reported that survival in each stage closely paralleled how severe the disease was.

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: Editorial proposing a staging system (TGM: tumour extent, grade, metastasis) for peritoneal mesothelioma, based on the authors' previously published patient series
• Who was studied: 33 patients with peritoneal mesothelioma treated at the authors' institution (Washington Cancer Institute, Washington DC) and previously reported by the authors. The institution had received 40 referred patients with peritoneal mesothelioma over the previous 12 years.
• Main results:
  • Variables significantly predictive of survival in the 33 patients: completeness of cytoreduction score below 2 (P=0.0002), metastasis (P=0.001), prior surgical score below 2 (P=0.002), female gender (P=0.003), second-look surgery (P=0.019), and Peritoneal Cancer Index below 28 (P=0.025).
  • Two of the prognostic factors, metastasis and the Peritoneal Cancer Index, were independent of treatment and were kept for the staging system.
  • Among the 33 patients, those with a Peritoneal Cancer Index below 28 showed significantly improved survival (P=0.025).
  • No statistically significant survival difference was found when patients were divided by pathological subtype. The authors nonetheless defined three grades: G1 (multicystic, adenomatoid and well-differentiated papillary), G2 (epithelial) and G3 (sarcomatous, biphasic and undifferentiated).
  • Stage I (any T, G1, M0): median survival 52.0 months; estimated 3-year survival 90–100%.
  • Stage II (T1, G2 or G3, M0): median survival 32.5 months; estimated 3-year survival 60–70%.
  • Stage III (T2, G2 or G3, M0): median survival 15.5 months; estimated 3-year survival 30–40%.
  • Stage IV (any T, any G, M1, meaning distant lymphatic or parenchymal metastasis): median survival 13.5 months; estimated 3-year survival less than 20%.
• The authors' conclusion: The authors proposed the TGM staging system for peritoneal mesothelioma and reported that, when their 33 patients were classified by stage, median survival in each stage closely paralleled the severity of the disease.

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: Peritoneal Mesothelioma, Staging, Mesothelioma, Asbestos Exposure, Cytoreductive Surgery, Chemotherapy, Median Survival, Metastasis.

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