Survival and prognostic factors in malignant pleural mesothelioma: a retrospective study of 314 patients in the west part of Japan

Our plain-English summary of Survival and prognostic factors in malignant pleural mesothelioma: a retrospective study of 314 patients in the west part of Japan, by S. Nojiri, K. Gemba, K. Aoe, et al (Japanese Journal of Clinical Oncology, 2011).

The study

• Authors: S. Nojiri, K. Gemba, K. Aoe, K. Kato, T. Yamaguchi, T. Sato, K. Kubota, T. Kishimoto
• Journal: Japanese Journal of Clinical Oncology
• Published: 2011;41(1):32-9
• Cited by: 56 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Objective: The objective in our study was to examine baseline and other characteristics associated with survival in patients with malignant pleural mesothelioma in Japan.

Methods: Three hundred and fourteen patients with an adjudicated diagnosis of mesothelioma were examined. Survival was evaluated by the Kaplan-Meier method with the log-rank test. The Cox model was used to estimate the hazard ratio for the possible prognostic factors.

Results: Of 314 patients, 223 (71%) died and only 40 (13%) were still alive at the end of the observation period starting from the day of diagnosis, while 51 (16%) were transferred to other hospitals or had the last health service contact before the end of the study period yielding the median survival of 308 days. In the multivariate analysis, age older than 70 years (hazard ratio = 2.17; 95% confidence interval, 1.36-3.46), non-epithelioid type (hazard ratio = 1.58; 95% confidence interval, 1.15-2.18), poor performance status (hazard ratio = 3.22; 95% confidence interval, 1.19-8.74), high white blood cell count (hazard ratio = 1.49; 95% confidence interval, 0.99-2.26) and high C-reactive protein level (hazard ratio = 1.80; 95% confidence interval, 1.06-3.06) were negatively associated with survival, after adjustment for other factors.

Conclusions: Some baseline conditions including old age, poor performance status, non-epithelioid type, high white blood cell count and high C-reactive protein level were determinants of poor survival of patients with malignant mesothelioma.

In plain English

This retrospective cohort study examined survival in 314 patients with malignant pleural mesothelioma. They were diagnosed between March 1996 and March 2006 at 26 hospitals in seven prefectures of western Japan, and a review committee confirmed the diagnoses. Most patients were men (87%), and the median age was 67 years. During follow-up, 223 patients (71%) died. Median survival from diagnosis was 308 days. After adjustment for other factors, shorter survival was associated with being in the oldest age group (hazard ratio 2.17 compared with under 60), non-epithelioid tumor type (1.58), the poorest performance status (3.22), a high C-reactive protein level (1.80) and a high white blood cell count (1.49, confidence interval 0.99 to 2.26). Past asbestos exposure, recorded for 197 patients (63%), was not associated with survival. Median survival was 710 days for patients who had surgical excision and 288 days for those who did not. The authors concluded that these baseline characteristics independently influenced poor survival, and that surgical excision was likely to have improved prognosis.

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 across multiple hospitals, using questionnaires about each patient
• Who was studied: 314 patients with malignant pleural mesothelioma whose diagnosis was confirmed by a review committee. They were diagnosed between March 1996 and March 2006 at 26 hospitals in seven prefectures in the west part of Japan. 87% were male, and the median age was 67 years. Of 328 patients reviewed, those with peritoneal (12), pericardial (1) and tunica vaginalis testis (1) mesothelioma were excluded.
• Exposure: The study did not examine an exposure as such. It examined possible prognostic factors (age, sex, tumor type, performance status, stage, smoking, past asbestos exposure, blood tests and treatments). Past asbestos exposure was recorded for 197 patients (63%), no exposure for 71 (23%), and unknown for 46 (15%). No fiber types, products or jobs are given.
• Main results:
  • Among all 314 patients, median survival was 308 days (interquartile range 281 to 368 days).
  • 223 patients (71%) died and 40 (12%) were still alive at the end of observation.
  • In the multivariate (Cox) analysis, patients in the oldest age group (70 and over) had a hazard ratio of 2.17 (95% CI 1.36 to 3.46) compared with those under 60.
  • Non-epithelioid tumors had a multivariate hazard ratio of 1.58 (95% CI 1.15 to 2.18) compared with epithelioid tumors. Median survival was 427, 319 and 183 days for the epithelioid, mixed and sarcomatoid types respectively.
  • Compared with performance status 0 or 1, the multivariate hazard ratio was 2.17 (95% CI 1.51 to 3.12) for performance status 2 or 3. It was 3.22 (95% CI 1.19 to 8.74) for performance status 4, a group of 7 patients.
  • A C-reactive protein level above 4.0 mg/dl had a multivariate hazard ratio of 1.80 (95% CI 1.06 to 3.06) compared with below 0.3 mg/dl. Median survival was 569, 314 and 201 days for the below 0.3, 0.3 to 4.0 and above 4.0 mg/dl groups.
  • A white blood cell count above 10,000/mm3 had a multivariate hazard ratio of 1.49 (95% CI 0.99 to 2.26) compared with below 9000/mm3.
  • Sex, smoking status and past asbestos exposure were not associated with survival. For asbestos exposure, the crude rate ratio was 1.25 (95% CI 0.91 to 1.72) and the multivariate hazard ratio was 1.02 (95% CI 0.98 to 1.07).
  • Median survival was 710 days for the 67 patients treated with surgical excision and 288 days for those without it. The crude rate ratio for surgical excision was 0.37 (95% CI 0.26 to 0.54).
• The authors' conclusion: The authors concluded that old age, poor performance status, non-epithelioid type, high white blood cell count and high C-reactive protein level at diagnosis independently influenced poor survival. They also concluded that surgical excision was likely to have improved prognosis, while pleurodesis and chemotherapy seemed to have no major impact on survival.
• Limitations the authors state:
  • Because the study was retrospective, some information was lacking, such as symptoms like chest pain and shortness of breath.
  • The apparent effects of treatment must be interpreted with caution, because patients received various therapies in different combinations for different durations.
  • 51 patients (16%) were transferred or lost to contact before the study ended. The authors reported that their prognostic factors were similar to those of the other patients, and that median survival without them was 288 days.
  • The small proportion of women may partly explain why sex was not found to affect survival.

Topics

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

Medical terms in this study, explained in our Lexicon: Pleural Mesothelioma, Mesothelioma, Hazard Ratio, Median Survival, Multivariate Analysis, confidence interval, Non-epithelioid, Performance Status.

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• Prognostic factors in malignant pleural mesothelioma: a retrospective study — H. Suzuki, T. Hirashima, et al. (2012)
• Validation of prognostic factors in malignant pleural mesothelioma: a retrospective analysis of data from patients seeking compensation from the New South Wales Dust Diseases Board — S.C. Kao, J. Vardy, et al. (2013)
• The C-Reactive Protein/Albumin Ratio is a Novel Significant Prognostic Factor in Patients with Malignant Pleural Mesothelioma: A Retrospective Multi-institutional Study — S. Takamori, G. Toyokawa, et al. (2018)
• Outcome and prognostic factors of pleural mesothelioma after surgical diagnosis and/or pleurodesis — M. Baud, S. Strano, et al. (2013)
• Treatment and survival analyses of malignant mesothelioma in Japan — K. Gemba, N. Fujimoto, et al. (2013)

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