Predictors and Outcomes of Surgery in Peritoneal Mesothelioma: an Analysis of 2000 Patients from the National Cancer Database

Our plain-English summary of Predictors and Outcomes of Surgery in Peritoneal Mesothelioma: an Analysis of 2000 Patients from the National Cancer Database, by L. Bijelic, K. Darcy, J. Stodghill, et al (Annals of Surgical Oncology, 2020).

The study

• Authors: L. Bijelic, K. Darcy, J. Stodghill, C. Tian, T. Cannon
• Journal: Annals of Surgical Oncology
• Published: 2020;27(8):2974-2982
• Cited by: 24 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Introduction: Diffuse malignant peritoneal mesothelioma (DMPM) is a rare malignancy associated with poor outcomes. Recent reports have shown longer survival with radical surgery, usually combined with intraperitoneal chemotherapy. However, surgical interventions in these patients have not been extensively studied at a population level. The objective of this retrospective cohort study is to assess the prevalence of surgical and nonsurgical interventions for DMPM patients, the influence of surgery on survival outcomes, and the associations between demographic and clinical factors with treatments and outcomes.

Methods: This study included adult patients diagnosed with DMPM from 2003 to 2014 and registered in the National Cancer Database (NCDB). The primary outcome was overall survival. Histologically confirmed mesothelioma was defined using International Classification of Diseases (ICD)-3 codes 9050/3, 9051/3, 90523, and 9053/3 and peritoneum as primary affected organ using ICD codes C17-19, C22-24, C26, C42, C48, and C76. Relationships between demographic and clinical variables, surgical treatments, and survival outcomes were evaluated using logistic and Cox modeling and log-rank tests.

Results: A total of 2062 patients were identified, of whom 1055 (51%) did not receive any surgery while 701 (34%) received radical surgery. Patients receiving radical surgery had overall survival of 38.4 months compared with 7.1 months for patients without surgery (p < 0.001) and 41.8 months in patients who received both radical surgery and systemic chemotherapy.

Conclusions: Patients selected for and treated with radical surgery had significantly better overall survival compared with those receiving nonsurgical treatment. Patients newly diagnosed with DMPM should be evaluated for the possibility of receiving radical surgery.

In plain English

This retrospective cohort study used the US National Cancer Database to examine 2062 adults diagnosed with diffuse malignant peritoneal mesothelioma (abdominal lining cancer) from 2003 to 2014. The study did not examine asbestos exposure. Of these, 1055 (51.2%) had no surgery, 306 (14.8%) had limited surgery and 701 (34.0%) had radical surgery. The radical surgery rate did not change significantly over time. Median overall survival from diagnosis was 38.4 months with radical surgery, 32.4 months with limited surgery and 7.1 months with no surgery. In adjusted analysis, radical surgery was associated with a lower risk of death than no surgery (hazard ratio 0.50, 95% CI 0.43 to 0.57). Treatment at academic or research programs, living 30 or more miles from the facility, female sex and younger age were linked to higher odds of radical surgery. The authors cautioned that disease stage could not be included and that patients selected for surgery likely had a better outlook beforehand. They concluded that radical surgery in selected patients was associated with long survival and that newly diagnosed patients should be evaluated for it.

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 cohort study using a national hospital cancer registry database (National Cancer Database, NCDB)
• Who was studied: 2062 adults in the USA diagnosed with diffuse malignant peritoneal mesothelioma from 2003 to 2014 and recorded in the NCDB. The NCDB draws on more than 1500 accredited hospitals. Patients with pleural, genital tract or cystic mesothelioma were excluded. Median age was 63 years; 1149 (55.7%) were male and 1858 (90.1%) were White.
• Exposure: The study compared treatments, not asbestos exposure. Surgery was grouped as none, minimal or partial (limited) surgery, or radical surgery (total removal of the primary site, debulking, or en bloc removal with nearby organs). Chemotherapy and its timing relative to surgery were also studied.
• Main results:
  • Of the 2062 patients, 701 (34%) received radical surgery, 306 (14.8%) limited surgery and 1055 (51.2%) no surgery. The rate of radical surgery did not change significantly over the study period.
  • Median overall survival for the whole cohort was 15.6 months. Survival rates were 56%, 41% and 33% at 1, 2 and 3 years after diagnosis.
  • Median overall survival, measured from diagnosis, was 38.4 months among patients who received radical surgery, 32.4 months among those who received limited surgery and 7.1 months among those with no surgery.
  • In the adjusted (multivariate) analysis, compared with no surgery, the hazard ratio for death was 0.50 (95% CI 0.43 to 0.57) for radical surgery and 0.48 (95% CI 0.41 to 0.57) for limited surgery.
  • Among patients without surgery, median survival was 11 months for those who received chemotherapy and 3.3 months for those who did not.
  • Among radical surgery patients, median survival was 41.8 months with systemic chemotherapy and 26.7 months without it.
  • In an exploratory analysis of surgical patients, median survival was 65.9 months with chemotherapy during surgery (intraoperative) and 27.9 months with chemotherapy before surgery (neoadjuvant). No survival benefit was seen with neoadjuvant chemotherapy, though that group was small (50 patients). The authors assumed, but the database did not confirm, that most intraoperative therapy was HIPEC (heated chemotherapy delivered inside the abdomen).
  • Odds of receiving radical surgery were higher for patients treated at academic/research programs than at community cancer programs (odds ratio 2.75, 95% CI 1.67 to 4.52).
  • Odds of radical surgery were higher for patients living 30 miles or more from the treatment facility than for those living under 10 miles away (odds ratio 2.69, 95% CI 1.96 to 3.69).
  • Odds of radical surgery were higher for women than men (odds ratio 2.40, 95% CI 1.90 to 3.03).
  • Odds of radical surgery were lower for patients aged 75 or older than for those under 55 (odds ratio 0.28, 95% CI 0.18 to 0.45).
  • Private insurance/managed care compared with no insurance had an odds ratio of 1.87 (95% CI 0.92 to 3.81, p = 0.085) for radical surgery, which the table shows was not statistically significant. Residential area, community education level and household income were not significantly associated with radical surgery.
• The authors' conclusion: The authors concluded that, for patients who are good candidates for and are selected to receive radical surgery, surgery is associated with long survival, especially when combined with chemotherapy. In their view, every newly diagnosed patient with peritoneal mesothelioma should be evaluated for radical surgery by a multidisciplinary team that includes a surgeon experienced in peritoneal malignancies.
• Limitations the authors state:
  • Data from large national databases may contain errors in data collection or classification that cannot be checked against original patient files.
  • Peritoneal mesothelioma has no accepted staging system, so disease stage could not be included in the analysis.
  • Patients chosen for surgery differ in prognosis from those not chosen, so the survival difference partly reflects these underlying differences rather than surgery alone.
  • The database does not specify the type of intraoperative therapy. The authors assumed most of it was HIPEC.
  • The sample was small for the analysis of chemotherapy given before surgery.

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, Chemotherapy, Cohort Study, Overall Survival, Mesothelioma, Peritoneum.

Related studies

• Malignant Peritoneal Mesothelioma: National Practice Patterns, Outcomes, and Predictors of Survival — V. Verma, R.L. Sleightholm, et al. (2018)
• Iterative cytoreductive surgery and hyperthermic intraperitoneal chemotherapy for recurrent or progressive diffuse malignant peritoneal mesothelioma: clinicopathologic characteristics and survival outcome — C. Ihemelandu, L. Bijelic, et al. (2015)
• Outcomes of cytoreductive surgery with hyperthermic intraperitoneal chemotherapy for peritoneal mesothelioma and predictors of survival — S.N.S. Gilani, A. Mehta, et al. (2018)
• Is Cytoreductive Surgery with Hyperthermic Intraperitoneal Chemotherapy Justified for Biphasic Variants of Peritoneal Mesothelioma? Outcomes from the Peritoneal Surface Oncology Group International Registry — K.I. Votanopoulos, P. Sugarbaker, et al. (2018)
• Long-term Survival and Propensity Score Matched Outcomes of Bilateral vs. Unilateral Diaphragm Interventions in Cytoreductive Surgery plus Intra-peritoneal Chemotherapy — B. Singh, G. Singh, et al. (2018)
• Postoperative outcomes of laparoscopic vs open cytoreductive surgery plus hyperthermic intraperitoneal chemotherapy for treatment of peritoneal surface malignancies — G. Passot, N. Bakrin, et al. (2014)

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