Second Primary Cancers in a Population-Based Mesothelioma Registry

Our plain-English summary of Second Primary Cancers in a Population-Based Mesothelioma Registry, by C. Mensi, S. Stella, B. Dallari, et al (Cancers, 2023).

The study

• Authors: C. Mensi, S. Stella, B. Dallari, S. Rugarli, A.C. Pesatori, G.L. Ceresoli, D. Consonni
• Journal: Cancers
• Published: 2023;15(6)
• Cited by: 1 article, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Background: The presence of a second primary cancer (SPC) in patients with pleural mesothelioma (PM) may impact overall survival and suggest a common mechanism of carcinogenesis or an underlying germline genetic alteration.

Methods: We evaluated the occurrence of SPCs within PM cases collected from 2000 to 2018 by the Lombardy Mesothelioma Registry and their prognostic implications. Kaplan-Meier analysis was performed to estimate median survival times, together with univariate and multivariate Cox regression models to estimate hazard ratios (HR) and 95% confidence intervals (CI) of death.

Results: The median overall survival (OS) of the entire study population (N = 6646) was 10.9 months (95% CI: 10.4-11.2); patient age and histotype were the strongest prognostic factors. No substantial survival difference was observed by the presence of an SPC (10.5 months in 1000 patients with an SPC vs. 10.9 months in 5646 patients in the non-SPC group, HR 1.03, p = 0.40). Shorter OS in the SPC group was only observed in 150 patients with the non-epithelioid subtype (median OS of 5.4 vs. 7.1 months, HR 1.21, p = 0.03).

Conclusions: The diagnosis of an SPC did not influence the outcome of PM patients in the overall study population but was associated with shorter OS in non-epithelioid cases. Further studies are needed to clarify the role of SPCs as markers of genetic susceptibility in mesothelioma.

In plain English

This study used the Lombardy Mesothelioma Registry (Italy) to compare survival in pleural mesothelioma patients diagnosed 2000 to 2018 with and without a recorded second primary cancer (a separate cancer). Of 6688 patients, 1005 (15.0%) had one. Where the year was known (915 of these patients), almost all second cancers were diagnosed before the mesothelioma. Prostate cancer (men) and breast cancer (women) were most common. Overall median survival (6646 patients) was 10.9 months (95% CI 10.4 to 11.2). It was 10.5 months (95% CI 9.4 to 11.5) with a second cancer and 10.9 months (95% CI 10.5 to 11.3) without one (hazard ratio 1.03, 95% CI 0.96 to 1.11, p = 0.40). In non-epithelioid (sarcomatoid or biphasic) cases, it was 5.4 months (95% CI 4.8 to 6.8) with versus 7.1 months (95% CI 6.7 to 7.9) without a second cancer (hazard ratio 1.21, p = 0.03). Asbestos exposure was not associated with survival. The authors concluded that second cancers were common but not significantly associated with survival except in non-epithelioid cases. Genetic data on inherited susceptibility were unavailable.

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: Population-based registry study: retrospective analysis of mesothelioma registry records, with survival analysis (Kaplan-Meier and Cox regression)
• Who was studied: 6688 patients with pleural mesothelioma registered in the Lombardy Mesothelioma Registry (Lombardy region, northern Italy), diagnosed 2000 to 2018, with follow-up to 2021. Of these, 1005 had a recorded second primary cancer and 5683 did not. 6646 patients were used in the survival analysis after 42 were excluded because their diagnosis and death dates coincided.
• Exposure: The main factor studied was having a second primary cancer, recorded from medical records. Experts classified asbestos exposure from interviews as occupational or extra-occupational, and it was analyzed as ever versus never. Ever-exposed patients made up 63.5% of the second-cancer group and 66.5% of the other group. No fiber types are named.
• Main results:
  • Of 6688 pleural mesothelioma patients, 1005 (15.0%) had a recorded second primary cancer and 5683 (85.0%) did not.
  • The year of second-cancer diagnosis was available for 915 of the 1005 patients with a second cancer (1042 cancers). Almost all of these second cancers occurred before the mesothelioma diagnosis. 56 (5.5%) were diagnosed in the same year as the mesothelioma.
  • Among men, the most frequent second cancers were prostate cancer (38.0%), colorectal cancer (11.6%) and bladder cancer (10.4%). Among women, the most frequent was breast cancer (42.2%).
  • Median overall survival for all 6646 patients in the survival analysis was 10.9 months (95% CI 10.4 to 11.2).
  • Patients with a second cancer (1000 in the survival analysis) had a median survival of 10.5 months (95% CI 9.4 to 11.5) and 3-year survival of 11.1%. Patients without one (5646) had a median survival of 10.9 months (95% CI 10.5 to 11.3) and 3-year survival of 11.5%. The hazard ratio was 1.03 (95% CI 0.96 to 1.11), p = 0.40.
  • Among patients with non-epithelioid (biphasic or sarcomatoid) mesothelioma, median survival was 5.4 months (95% CI 4.8 to 6.8) in the 150 with a second cancer. It was 7.1 months (95% CI 6.7 to 7.9) in the 1086 without one (HR 1.21, p = 0.03; no confidence interval is given for this HR). Among epithelioid patients, no difference was found (14.7 vs 14.5 months, p = 0.94).
  • Of all 1138 second cancers, the authors identified those with an established link to asbestos. These were 33 (2.9%) laryngeal cancers, 18 (1.6%) lung cancers and 8 (0.7%) ovarian cancers.
  • Breast cancer was more often the second cancer in epithelioid than in non-epithelioid cases (17.1% vs 9.3% of second cancers, p = 0.02).
  • Asbestos exposure was not associated with survival in the whole study population (adjusted HR 0.99, 95% CI 0.93 to 1.05, ever versus never exposed).
  • Tumor subtype and age were strong predictors of survival. Sarcomatoid patients had an adjusted HR of 2.66 (95% CI 2.41 to 2.93) compared with epithelioid patients. Patients aged 75 and over had an adjusted HR of 1.84 (95% CI 1.62 to 2.10) compared with patients under 55.
• The authors' conclusion: The authors concluded that second primary cancers were common in this series but were not associated with a significant change in survival, except in non-epithelioid pleural mesothelioma. They stated that genetic analysis is needed to show any inherited component.
• Limitations the authors state:
  • Genetic information was not routinely collected, so the authors could not test for inherited mutations related to BAP1 syndrome.
  • Clinical data, including second cancers, were collected retrospectively from medical records, which were not always complete.
  • Some patients were too ill to be interviewed or died early, so information on asbestos exposure, smoking and history was lost. In those cases close relatives were interviewed instead.

Topics

Medical terms in this study, explained in our Lexicon: Mesothelioma, Pleural Mesothelioma, Overall Survival, Mechanism of Carcinogenesis, Median Survival, Hazard Ratio, confidence interval, Median Overall Survival.

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• Differences in cancer survival by sex: a population-based study using cancer registry data — N. Afshar, D.R. English, et al. (2018)
• Malignant mesothelioma incidence by nation-wide cancer registry: a population-based study — K. Tomasson, G. Gudmundsson, et al. (2016)
• Impact of malignant mesothelioma in Taiwan: a 27-year review of population-based cancer registry data — L.J. Lee, Y.Y. Chang, et al. (2010)
• Differences in cancer survival by remoteness of residence: an analysis of data from a population-based cancer registry — N. Afshar, D.R. English, et al. (2020)
• Therapeutic radiation for lymphoma and risk of second primary malignant mesothelioma — E.T. Chang, E.C. Lau, et al. (2017)

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