The impact of age on the efficacy of radiotherapy in pleural mesothelioma patients receiving trimodality therapy: a population-based study of the SEER database

Our plain-English summary of The impact of age on the efficacy of radiotherapy in pleural mesothelioma patients receiving trimodality therapy: a population-based study of the SEER database, by J. Yang, L. Xia, H. Jie, et al (Journal of Thoracic Disease, 2024).

The study

• Authors: J. Yang, L. Xia, H. Jie, T. Wang, C. Guo, C. Liu, H. Liao, J. Mei, Q. Pu, L. Liu
• Journal: Journal of Thoracic Disease
• Published: 2024;16(10):6462-6474
• Cited by: 1 article, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Background: Pleural mesothelioma (PM) is a highly aggressive tumor with poor survival outcomes. The role of additional radiotherapy for PM patients who have received surgery and chemotherapy remains controversial. In this study, we aim to evaluate the impact of age on the effectiveness of additional radiotherapy in order to identify the populations that may benefit from the trimodality therapy.

Methods: We designed a case-control study and retrospectively selected PM patients who underwent surgery and chemotherapy, with or without radiotherapy, from the Surveillance, Epidemiology, and End Results (SEER) database (2000-2019). Kaplan-Meier curves were performed to compare the overall survival (OS) and cancer-specific survival (CSS) between the surgery + chemotherapy group and the trimodality therapy group. Propensity score matching (PSM) was used to balance the clinical characteristics and reduce potential confounding effects.

Results: A total of 745 patients were selected, of which 515 received surgery + chemotherapy and 230 received trimodality therapy. For patients aged 50 to <65 years, additional radiotherapy showed better OS (3-year: 34.78% vs. 23.92%, P=0.02) and CSS (3-year: 36.15% vs. 25.46%, P=0.04) compared to surgery + chemotherapy. Similar results were observed after PSM (3-year OS: 38.76% vs. 26.53%, P=0.02; 3-year CSS: 40.49% vs. 26.92%, P=0.02). No significant benefit of radiotherapy was seen for patients aged <50 and ≥65 years, both before and after PSM.

Conclusions: Our findings reveal that trimodality therapy is associated with better OS and CSS compared to surgery + chemotherapy for patients aged 50 to <65 years. These patients might obtain a benefit from additional radiotherapy.

2024 AME Publishing Company. All rights reserved.

In plain English

This study used records from the US Surveillance, Epidemiology, and End Results (SEER) cancer database to ask whether adding radiotherapy to surgery and chemotherapy (trimodality therapy) was linked to longer survival in people with pleural mesothelioma, and whether this depended on age. The authors described the design as a retrospective case-control study. They selected 745 adult patients diagnosed from 2000 to 2019: 515 had surgery plus chemotherapy and 230 also had radiotherapy. Across all patients, survival did not differ significantly between the two groups. Among patients aged 50 to under 65, trimodality therapy was associated with better 3-year overall survival (34.78% vs. 23.92%) and cancer-specific survival (36.15% vs. 25.46%). After matching patients on clinical characteristics, the figures were 38.76% vs. 26.53% and 40.49% vs. 26.92%. No significant benefit was seen in patients under 50 or aged 65 and older. The authors concluded that patients aged 50 to under 65 may benefit from added radiotherapy. They noted the retrospective design, missing details on surgery, radiation dose and smoking, and small age subgroups.

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 analysis of a population-based cancer registry (SEER), described by the authors as a case-control study, with propensity score matching
• Who was studied: 745 adults (aged 18 or older) in the US SEER database with pathologically diagnosed pleural mesothelioma (epithelioid, biphasic or unclear histological type), diagnosed 2000 to 2019, who had surgery and chemotherapy. Of these, 515 had surgery plus chemotherapy and 230 had trimodality therapy.
• Exposure: Treatment exposure: radiotherapy added after surgery and chemotherapy (trimodality therapy), compared with surgery plus chemotherapy alone. Radiation dose and surgical details were not available. Asbestos exposure was not studied.
• Main results:
  • In all 745 patients, there was no statistically significant difference between the surgery plus chemotherapy group and the trimodality therapy group in cancer-specific survival (P=0.32) or overall survival (P=0.10).
  • In all patients, 1-year overall survival was 66% for surgery plus chemotherapy and 77% for trimodality therapy. At 3 years it was 21% and 26%, and at 5 years 11% and 13%.
  • Before matching, in patients aged 50 to under 65, trimodality therapy was associated with better survival than surgery plus chemotherapy: 3-year overall survival 34.78% vs. 23.92% (P=0.02) and 3-year cancer-specific survival 36.15% vs. 25.46% (P=0.04).
  • After propensity score matching, in patients aged 50 to under 65, trimodality therapy was still favored: 3-year overall survival 38.76% vs. 26.53% (P=0.02) and 3-year cancer-specific survival 40.49% vs. 26.92% (P=0.02).
  • No survival benefit of added radiotherapy was observed in patients under 50 or aged 65 and older, either before or after matching.
  • In a pre-matching analysis of clinical factors, added radiotherapy was a protective factor in patients aged 50 to under 65 (hazard ratio 0.75, P=0.04).
  • In patients under 50 who had complete surgery, added radiotherapy indicated unfavorable survival (P=0.02). The authors advised caution because of the small sample size.
  • When patients were split into seven age groups, added radiotherapy showed potential survival benefit only in the 50–54, 55–59 and 60–64 age groups.
• The authors' conclusion: The authors concluded that trimodality therapy was associated with improved survival compared with surgery plus chemotherapy in patients aged 50 to under 65, but not in younger or older patients, and that patients aged 50 to under 65 may derive potential benefit from added radiotherapy.
• Limitations the authors state:
  • The retrospective design may have introduced selection bias and information bias.
  • The SEER database does not provide details of surgery or radiotherapy dose, or data on how patients responded to radiotherapy.
  • Smoking information was missing, so its effect could not be evaluated.
  • Each of the seven age groups in the interaction analysis was small, so that analysis could only show a trend.
  • Treatment methods varied among patients despite matching and sensitivity analyses.

Topics

Medical terms in this study, explained in our Lexicon: Pleural Mesothelioma, Trimodality Therapy, SEER, Chemotherapy, Case-Control Study, Epidemiology, Kaplan-Meier Curve, Overall Survival.

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