Prognostic factors and treatment outcomes of malignant pleural mesothelioma in Eastern Asian patients - A Taiwanese study

Does mediastinal lymph node involvement influence the surgical outcome in malign pleural mesothelioma?

BACKGROUND

This study examined the effect of metastatic mediastinal lymph node involvement on the prognosis of patients with malignant pleural mesothelioma (MPM) who underwent extrapleural pneumonectomy (EPP) or extended pleurectomy (E/P) and also to assess the effect of metastatic mediastinal lymph node involvement on the prognosis of patients with MPM in these group of patients.

METHODS

This retrospective study included 84 patients with MPM (66 men [78.6%] and 18 women [21.4%]) who underwent EPP (n = 44) or E/P (n = 40) at our institution between January 2001 and July 2019. Survival analyses were performed according to histopathology, nodal status, and surgical approach.

RESULTS

In the EPP group, patients with T2-N2 status had a significantly better mean survival (17 ± 2.1 months) than patients with T3-N2 (7.3 ± 1.6 months) or T4-N2 (3.2 ± 1.1 months) status (p = .001). In the E/P group, patients with T2-N2 status had a mean survival of 18 ± 1.1 months, while patients with T3-N2 and T4-N2 status had mean survival durations of 6.6 ± 1.6 and 4.8 ± 1.2 months, respectively (p = .159). In both treatment groups, the survival rates of patients with epithelial tumors were better than those of patients with non-epithelial tumors, independent of N status. None of the patients with N2 disease survived until 5 years postoperatively.

CONCLUSION

In summary, our results suggested that mediastinal lymph node metastasis negatively influenced the prognosis of patients with T3 MPM, regardless of treatment by EPP or E/P. Under these circumstances, preoperative cervical mediastinoscopy or endobronchial ultrasound-guided transbronchial needle aspiration may be considered for patients with high-stage MPM who are scheduled for surgery with curative intent. In our study, N2 status was spotted as a significant factor affecting survival, nevertheless its significance in survival of pleural mesothelioma patients should be analyzed in multi-centered studies.

Explaining the Invisibility of Asbestos-Related Diseases in the Taiwan Workers' Compensation System

Occupational asbestos exposure was prevalent in Taiwan, but asbestos-related diseases (ARDs) have rarely been recognized. We conducted in-depth face-to-face interviews with 16 patients with ARDs. All of them had worked in industries known for high asbestos exposure. However, only three patients had filed workers' compensation (WC) claims, and of them, only two patients were approved. Reasons for the low compensation rate of ARDs could be divided into institutional barriers related to the flaws of the WC system and non-institutional barriers related to the knowledge status, causal interpretation, and social situations of individual workers. The Labor Occupational Accident Insurance and Protection Act passed in April 2021 has responded to the under-compensation of occupational diseases. However, the new act's effects toward improving the recognition of ARDs remain questionable. Our findings indicated that additional efforts are needed to remove non-institutional barriers hindering workers' ability to ensure their compensation rights.

Survival of Korean Patients with Malignant Pleural Mesothelioma Compensated for the Asbestos Injury Relief

Background: The purpose of this study was to identify the epidemiologic characteristics and prognostic factors for malignant pleural mesothelioma in Korea, which are currently insufficient. The data were derived from malignant mesothelioma patients who registered under the Asbestos Injury Relief Act; Methods: A total of 728 patients received compensation from the Asbestos Injury Relief Act due to malignant mesothelioma between 2011 and 2015. Of these, 313 patients (43.0%) with malignant pleural mesothelioma were included in the study. The study variables were sex (male, female), age at diagnosis (<59, 60–69, ≥70), smoking history (yes, no), surgery (yes, no), chemotherapy (yes, no), occupational exposure to asbestos (yes, no), and histological subtype (epithelioid, nonepithelioid); Results: Median survival of mesothelioma was 8.0 months (95% confidence interval: 6.2 to 9.8). The 1-year, 2-year, and 5-year survival rates (%) were 43.5%, 23.6%, and 12.5%, respectively. In multivariate analysis of Cox’s proportional hazards model; sex, age, smoking history, occupational asbestos exposure, and histological subtype were not significant prognostic factors, but surgery and chemotherapy combined was a significant predictor; Conclusions: Although the representativeness of these data is limited, our study estimates the epidemiologic characteristics of malignant pleural mesothelioma. Non-occupational exposure had a similar prognosis to occupational asbestos exposure, and there was no sex difference. In addition, it was found that receiving a combination of surgery and chemotherapy affects the survival rate, but there is a limitation in that factors such as performance status, comorbidities, and stage that contribute to survival are not considered.

Acquired multiple mutations ALK I1171N, L1196M and G1202R mediate lorlatinib resistance in EML4-ALK-rearranged malignant pleural mesothelioma: a case report

EML4-ALK rearranged malignant pleural mesothelioma (MPM) is rare and its responses to anaplastic lymphoma kinase (ALK) inhibitors, including alectinib and lorlatinib, remain unexplored. In this case report, we describe a patient with EML4-ALK-rearranged stage IIIB MPM who was administered with alectinib and lorlatinib as first-line and fourth-line therapy, respectively. He had remarkable response evaluated as partial response on both regimens lasting approximately 3.5 months on each regimen. His plasma samples were collected during the treatment course and submitted for targeted sequencing to understand the molecular mechanisms of his therapeutic resistance. Sequencing analysis revealed the emergence of ALK I1171N and L1196M at alectinib progression. Meanwhile, ALK I1171N, L1196M, and G1202R mutations were identified at lorlatinib progression, wherein L1196M is confirmed to be in cis to G1202R. We speculate that these multiple mutations synergistically mediated his resistance to both alectinib and lorlatinib. Our report describes the detection of EML4-ALK rearrangement in a patient with MPM who had remarkable therapeutic response with ALK inhibitors. Moreover, our case also revealed acquired mechanisms of lorlatinib resistance mediated by multiple mutations ALK I1171N, L1196M, and G1202R, contributing an incremental step to our understanding of the complexity of acquired resistance mechanisms in sequential ALK inhibitor therapy.

The reviews of this paper are available via the supplemental material section.

Clinical prognostic factors in pleural mesothelioma: best supportive care and anti-tumor treatments in a real-life setting

BACKGROUND

This study aims to investigate patient- and disease characteristics associated with survival in malignant pleural mesothelioma (MPM) patients with anti-tumor treatment or with best supportive care (BSC).

MATERIALS AND METHODS

Consecutive MPM cases diagnosed in North Denmark Region from 1972 to 2015 were reevaluated and verified by two pathologists using modern immunohistochemical techniques. Danish registries and hospital records were used to gather patient-, asbestos exposure-, and disease information.

RESULTS

Of the 279 patients, anti-tumor treatment was administered to 184 patients (66.0%). All of those received chemotherapy alone or as part of a multimodal treatment, where pemetrexed was given to 126 (68.5%) patients. Asbestos exposure was documented in 92.5% of all patients. In the treated group, mean age was lower (66 years versus 74 years, p < 0.01), rate of occupational asbestos exposure was higher (74.5 versus 54.7%, p < 0.01), more patients had better performance score (98.4 versus 60%, p < 0.01) and stage was lower (81 versus 63.2%, p < 0.01) compared to the BSC group. Multivariate analysis showed that epithelioid subtype was the only common prognostic factor for OS in both groups. In BSC patients, good PS and female gender was associated with improved OS. Median overall survival (OS) was 17 versus 4 months (p < 0.01), and independently of the histopathological subtype, the median and 2-year survival was higher in the treated versus the BSC group (p < 0.02).

CONCLUSIONS

This retrospective study showed that epithelioid subtype is the only independent positive prognostic factor of survival in treated patients with MPM. For BSC patients, the epithelioid subtype, good PS, and female gender were positive prognostic factors, while age and comorbidities were not significant. This study with long-term follow-up of treated and BSC MPM patients can contribute to the clinical stratification of patients. Further validation is appropriate to verify these findings.

Clustering of malignant pleural mesothelioma in asbestos factories: a subgroup analysis in a 29-year follow-up study to identify high-risk industries in Taiwan

OBJECTIVE

Exposure to asbestos is the major cause for malignant pleural mesothelioma (MPM), but the causal link of individual cases is difficult to establish for lack of exposure information and long disease latency.

METHODS

We established a retrospective cohort of workers employed in asbestos industries during the period of 1950-1989 and the occurrence of MPM during the period of 1980-2009 was examined with the Taiwan Cancer Registry. Estimated rate ratios (eRRs) were computed for each factory where any case of MPM was diagnosed by assuming Poisson distribution with a minimal latency of 20 years.

RESULTS

A total of 18 MPM (17 males, 1 female) in eight factories were found. The incidence rate of MPM for the eight factories was 18.0 per million, ranging from 6.2 per million (military factory) to 268.2 per million (asbestos cement). We observed significantly increased risks for MPM in asbestos cement, thermal insulation and shipbuilding industries, with eRR (genders combined) of 113.6, 87.5 and 15.8, respectively. The sensitivity analyses considering latency showed similar findings in latency ≥30 years, and the shipbuilding industry presented a significant eRR given a latency ≥40 years. The gender-specific eRR showed similar results in men, but high eRR of 729.6 was observed in an asbestos cement factory where a female MPM was diagnosed.

CONCLUSIONS

This nationwide study in Taiwan comprehensively shows that different asbestos manufacturing processes, including asbestos cement, thermal insulation and shipbuilding industries, were at significantly increased risks for MPM. We recommend to establish a medical screening programme for workers previously exposed to asbestos to identify MPM and other asbestos-related diseases at an earlier stage.