Nationwide prospective registry database of patients with newly diagnosed untreated pleural mesothelioma in Japan

Our plain-English summary of Nationwide prospective registry database of patients with newly diagnosed untreated pleural mesothelioma in Japan, by S. Hasegawa, Y. Shintani, T. Takuwa, et al (Cancer Science, 2024).

The study

• Authors: S. Hasegawa, Y. Shintani, T. Takuwa, K. Aoe, K. Kato, N. Fujimoto, Y. Hida, M. Morise, Y. Moriya, T. Morohoshi, H. Suzuki, M. Chida, S. Endo, M. Kadokura, M. Okumura, S. Hattori, H. Date, I. Yoshino
• Journal: Cancer Science
• Published: 2024;115(2):507-528
• Cited by: 7 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Due to the scarcity of large-sized prospective databases, the Japanese Joint Committee for Lung Cancer Registry conducted a nationwide prospective registry for newly diagnosed and untreated pleural mesothelioma. All new cases diagnosed pathologically as any subtype of pleural mesothelioma in Japan during the period between April 1, 2017, to March 31, 2019, were included before treatment. Data on survival were collected in April 2021. The eligible 346 patients (285 men [82.3%]; 61 women [17.7%]; median age, 71.0 years [range, 44-88]) were included for analysis. Among these patients, 138 (39.9%) underwent surgery, 164 (47.4%) underwent non-surgical therapy, and the remaining 44 (12.7%) underwent best supportive care. The median overall survival for all 346 patients was 19.0 months. Survival rates at 1, 2, and 3 years for all patients were, 62.8%, 42.3%, and 26.5%, respectively. Median overall survival was significantly different among patients undergoing surgery, non-surgical treatment, and best supportive care (32.2 months vs. 14.0 months vs. 3.8 months, p < 0.001). The median overall survival of patients undergoing pleurectomy/decortication and extrapleural pneumonectomy was 41.8 months and 25.0 months, respectively. Macroscopic complete resection resulted in longer overall survival than R2 resection and partial pleurectomy/exploratory thoracotomy (41.8 months vs. 32.2 months vs. 16.8 months, p < 0.001). Tumor shape, maximum tumor thickness, and sum of three level thickness were significant prognostic factors. The data in the prospective database would serve as a valuable reference for clinical practice and further studies for pleural mesothelioma.

© 2023 The Authors. Cancer Science published by John Wiley & Sons Australia, Ltd on behalf of Japanese Cancer Association.

In plain English

This nationwide prospective registry enrolled people in Japan newly diagnosed with pleural mesothelioma from April 1, 2017, to March 31, 2019, before treatment. It analysed 346 patients from 54 institutions (285 men, 61 women; median age 71.0 years). Asbestos exposure was recorded for 67.1%; fiber types were not reported. Of these, 138 had surgery, 164 non-surgical treatment and 44 best supportive care. Median overall survival, counted from diagnosis, was 19.0 months for all patients (95% confidence interval 15.4 to 22.3), 32.2 months in the surgery group, 14.0 months with non-surgical treatment and 3.8 months with supportive care alone. Median survival was 41.8 months among patients who had pleurectomy/decortication and 25.0 months among those who had extrapleural pneumonectomy, but the authors cautioned that possible patient selection bias made comparing techniques inappropriate. Patients whose visible tumor was completely removed also had median survival of 41.8 months. Tumor shape and tumor thickness were significant prognostic factors. The authors concluded that complete removal of visible tumor is a reasonable surgical goal. They noted most participating hospitals were academic or large centers and nivolumab use was not recorded.

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: Nationwide prospective observational cohort study (registry), the ninth project of the Japanese Joint Committee for Lung Cancer Registry
• Who was studied: Patients in Japan newly diagnosed with any subtype of pleural mesothelioma between April 1, 2017, and March 31, 2019. Diagnosis was by pathology, including cytology, and no patient had been treated before registration. 348 cases were registered from 54 institutions. After one duplicate and one case with multiple missing values were removed, 346 were analysed: 285 men (82.3%) and 61 women (17.7%), median age 71.0 years (range 44 to 88). Survival data were collected in April 2021.
• Exposure: This was a treatment and outcome study, not an exposure study. Asbestos exposure was recorded as a patient characteristic: yes in 232 patients (67.1%), no in 71 (20.5%) and unknown in 43 (12.4%). No fiber types, products, jobs or doses were reported. The treatments compared were surgery (extrapleural pneumonectomy, pleurectomy/decortication, or partial pleurectomy/exploratory thoracotomy), non-surgical therapy (chemotherapy with or without radiation) and best supportive care.
• Main results:
  • Of the 346 patients, 138 (39.9%) underwent surgery, 164 (47.4%) non-surgical therapy and 44 (12.7%) best supportive care.
  • For all 346 patients, median overall survival, measured from diagnosis at registration, was 19.0 months (95% CI 15.4 to 22.3). Survival rates were 62.8% at 1 year, 42.3% at 2 years and 26.5% at 3 years.
  • Median overall survival, measured from diagnosis, was 32.2 months in the surgery group, 14.0 months in the non-surgical treatment group and 3.8 months in the best supportive care group. The authors reported significant differences among the three groups.
  • Among surgical patients, median overall survival was 25.0 months for extrapleural pneumonectomy, 41.8 months for pleurectomy/decortication and 17.5 months for partial pleurectomy/exploratory thoracotomy. Survival after pleurectomy/decortication was significantly longer than after partial pleurectomy/exploratory thoracotomy; survival after extrapleural pneumonectomy was not.
  • Macroscopic complete resection, meaning no visible tumor was left, was achieved in 69.6% (96/138) of surgical patients. Median overall survival in this group was 41.8 months, significantly longer than for R2 resection (32.2 months) and for partial pleurectomy/exploratory thoracotomy (16.8 months). Survival did not differ significantly between the R0-1 and R1 subgroups.
  • Among the 138 surgical patients, postoperative deaths were 0.7% (1/138) within 30 days and 4.3% (6/138) within 90 days.
  • Median overall survival was 26.7 months for minimal tumors (n = 68), 21.3 months for nodular tumors (n = 96) and 15.0 months for rind-like tumors (n = 178). Survival was significantly longer in the minimal group (p = 0.007) and the nodular group (p = 0.029) than in the rind-like group.
  • Median overall survival was 27.0 months when maximum tumor thickness was under 5.1 mm (n = 91), compared with 15.5 months at 5.1 mm or more (n = 255) (p = 0.013). By sum of three-level thickness, it was 26.3 months under 13 mm (n = 101), compared with 15.5 months for 13 to under 60 mm (n = 203, p = 0.022) and 12.0 months for 60 mm or more (n = 42, p = 0.008).
  • Relapse occurred in 74 (77.1%) of the 96 patients with macroscopic complete resection. Median progression-free survival for 93 of these patients was 16.6 months.
  • Survival differed significantly between clinical stage groups under both the seventh and eighth staging systems. For pathological stages in surgical patients, the difference was not statistically significant under the seventh system (p = 0.080) but was significant under the eighth system (p = 0.005).
• The authors' conclusion: The authors concluded that macroscopic complete resection is a reasonable goal for pleural mesothelioma surgery. They described tumor shape and thickness as promising candidates for future staging descriptors, and said the prospective database would serve as a reference for clinical practice and further studies.
• Limitations the authors state:
  • There may be sampling bias. The registry did not collect all pleural mesothelioma cases in Japan, and most participating institutions were academic centers or large hospitals, so the results may not reflect the real-world situation.
  • The results might not directly translate to other countries because of differences in racial composition, cultural habits and medical systems.
  • The case report form did not include nivolumab treatment, because registration began a year before nivolumab was approved in Japan. Agents listed as "others" were presumed, but not verified, to be nivolumab.
  • There may be patient selection bias, including conversion from pleurectomy/decortication to extrapleural pneumonectomy, so the authors considered it inappropriate to draw conclusions comparing surgical techniques.

Topics

The National Library of Medicine indexes this study under subjects our site covers: Lung cancer, Mesothelioma.

Medical terms in this study, explained in our Lexicon: Pleural Mesothelioma, Lung Cancer, Median Overall Survival, Pleurectomy/Decortication (P/D), Extrapleural Pneumonectomy (EPP), Overall Survival, Thoracotomy.

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