Pleural thickness after neoadjuvant chemotherapy is a prognostic factor in malignant pleural mesothelioma

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

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.

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.

Pleural Fluid-to-Blood BNP Ratio May Contribute to Prognosis in Malignant Pleural Mesothelioma

BACKGROUND

Brain natriuretic peptide (BNP) seems to be produced from malignant mesothelial cells other than cardiomyocytes. We aimed to evaluate whether an increased pleural fluid-to-blood BNP ratio in patients with malignant pleural mesothelioma (MPM) could facilitate prognosis beyond diagnosis.

MATERIALS AND METHODS

Patients with MPM were included (observational study). One- and two-year survival and factors affecting it were tested. To evaluate the prognostic significance of the natriuretic peptide precursor B (NPPB) gene expression in MPM, we constructed a survival curve from data derived from The Cancer Genome Atlas.

RESULTS

Nineteen consecutive patients with MPM were included (age: 67 (61, 80), male 78.9%). One- and two-year survival were 52.6% and 31.6%, respectively. Age, performance status, and the other variables tested did not differ between survivors and non-survivors. Non-survivors presented higher pleural fluid BNP in two years (699 (210, 5000) vs. 379.5 (5, 567), p = 0.036) and BNP ratios than survivors (1-year: 28.75 (4.05, 150.24) vs. 3.49 (0.3, 26) p = 0.001, 2-years: 22.8 (2.42, 150.24) vs. 3.49 (0.3, 7.76), p = 0.001). One- and two-year survival rates in patients with BNP ratios above/equal to the median value (8.82) were 20% and 0%, and 88.9% and 66.7%, respectively, in patients with BNP ratios below 8.82 (p = 0.006 and p = 0.002, respectively). MPM patients with low NPPB expression presented significantly higher survival rates compared to patients with higher expressions (p = 0.032).

CONCLUSION

A high pleural fluid/blood BNP ratio, an easily performed in everyday practice, costless biomarker seems to predict poorer survival better than the commonly reported prognostic factors in MPM.

Importance of Histopathological Grading for Treatment Selection in Malignant Mesothelioma

BACKGROUND

Complexities in TNM staging in epithelioid malignant pleural mesothelioma (MPM) may lead to errors in treatment selection, leading to major surgical interventions in patients with low survival expectations.

METHODS

Sixty-nine stage I epithelioid MPM patients, including 27 patients treated with pleurectomy/decortication (P/D) and multimodal therapy (MMT) (the P/D [MMT] group), and 42 patients treated with chemotherapy or chemoradiotherapy (the CRT group), were included in the study. After an initial evaluation of overall survival, all patients were grouped in terms of histopathological parameters and treatment types, and then, a secondary survival evaluation was performed for the groups.

RESULTS

Forty-one patients were male, the mean age was 61.8 years. The median survival time was 26 months in the P/D (MMT) group, and 19.6 months in the CRT group, but the difference was not statistically significant. After grouping according to pathological criteria, a median survival time of 32.4 ± 2.9 months in the P/D (MMT) group and 21.9 ± 3.2 months in the CRT group was obtained among patients with histopathological low-grade tumors. Among patients with high-grade tumors, the median survival time was 18.3 ± 2.6 months in the P/D (MMT) group and 17 ± 4.4 months in the CRT group. Among patients with low-grade tumors, the P/D (MMT) group had longer survival. Median survival times were similar among patients with high-grade tumors.

CONCLUSION

In epithelioid MPM, histopathological grading by video-assisted thoracic surgery pleural biopsy can prove accurate in selecting patients for P/D and MMT.

Tumor thickness in mesothelioma predicts differential response to neoadjuvant therapy and survival

OBJECTIVE

Neoadjuvant systemic therapy in resectable malignant pleural mesothelioma remains controversial and demonstrates variable responses. We sought to evaluate tumor thickness as a predictor of response to neoadjuvant therapy and as a prognostic marker for overall survival.

METHODS

Data from patients who underwent neoadjuvant therapy followed by cytoreductive surgery from 2002 to 2019 were reviewed. Baseline and postneoadjuvant therapy tumor thickness were measured on computed tomography. Radiological tumor response was categorized as progressive disease (≥20% increase), partial response (≥30% decrease), or stable disease (in between). Tumor response outcomes were modeled using logistic regression and multinomial regression models. Overall survival was evaluated based on tumor thickness and tumor response.

RESULTS

Of the 143 patients reviewed, 36 (25%) had progressive disease, 54 (38%) had stable disease, and 56 (39%) had partial response. The baseline tumor thickness of the progressive disease group (36 mm) was lower than in both stable disease and partial response groups (both 63 mm; P < .001). Both logistic regression and multinomial regression analyses demonstrated that thicker baseline tumor thickness was associated with decreased probability of progressive disease and increased probability of partial response. In a multivariable Cox model, thicker postneoadjuvant therapy tumor thickness was associated with worse overall survival (hazard ratio, 1.01, 95% confidence interval, 1.00-1.01, P = .008). The same trend was observed for thicker baseline tumor thickness (hazard ratio, 1.02, 95% confidence interval, 1.01-1.04, P = .008), and the risk was decreased in tumors with partial response (hazard ratio, 0.98, 95% confidence interval, 0.96-0.100, P = .014).

CONCLUSIONS

We present the first study demonstrating the relationship between baseline tumor thickness and differential radiographic response to neoadjuvant therapy and survival. Further studies are needed to validate tumor thickness as both a prognostic and predictive biomarker.

Impact of Pleural Thickness on Occurrence of Postoperative Complications in Patients with Malignant Pleural Mesothelioma

OBJECTIVES

The rates of postoperative mortality and morbidity are high in patients with malignant pleural mesothelioma (MPM). Therefore, it is important to identify variables that increase the risk of postoperative complications. Pleural thickness has recently been identified as a prognostic indicator in patients with MPM. The aim of this study was to investigate clinical variables, including pleural thickness, that contribute to postoperative complications in patients with MPM.

PATIENTS AND METHODS

A total of 47 patients who underwent surgical excision of MPM between 2005 and 2021 were enrolled in this study. Correlations between postoperative complications within 90 days of surgery and preoperative clinical factors were investigated.

RESULTS

A total of 27 patients underwent extrapleural pneumonectomy (EPP), and the remaining 20 underwent pleurectomy/decortication (P/D). Macroscopic complete resections were obtained in all but three patients. Of the 47 patients, 23 (49%) experienced postoperative complications of grade 3 or worse. The major complication in patients with EPP was respiratory failure (n = 6), whereas the major complication in patients with P/D was prolonged air leakage (n = 7). Univariate logistic regression analysis found a correlation between postoperative complications and age, surgical side, and pleural thickness, while multivariate logistic regression analysis found surgical side (p = 0.04, 95% Cl 1.10-21.71, OR 4.90) and pleural thickness (p = 0.03, 95% Cl 1.21-23.00, OR 5.26) to significantly influence the occurrence of postoperative complications.

CONCLUSIONS

Pleural thickness has a significant effect on the occurrence of postoperative complications. Patients with thick pleura on the right side are at greater risk of postoperative complications.

Long-term outcomes and risk factors of residual thoracic spaces after pleurectomy/decortication for mesothelioma

OBJECTIVES

The residual thoracic spaces (RTS) after pleurectomy/decortication (P/D) remain unexplored to date. Hence, this study aims to examine the details and risk factors of RTS during the 3 post-P/D months.

METHODS

We retrospectively examined patients who underwent neoadjuvant chemotherapy, followed by P/D for malignant pleural mesothelioma from September 2012 to December 2020. The RTS group included cases of residual thoracic cavity unaccompanied by pleural effusion on 3 postoperative months computed tomography. We determined risk factors for RTS using univariable and multivariable analyses.

RESULTS

Of 170 patients examined, 58 (34.1%) were in the RTS group and 112 (65.9%) in the non-RTS group. In the RTS group, 43 patients recovered from RTS during the follow-up period; 4 patients developed chronic fistular empyema, while 2 required fenestration and 2 were thoracoscopic debridement. Besides, 11 patients exhibited RTS continuously. The univariable analysis revealed that compared with the non-RTS group, the RTS group reported a significantly longer postoperative air leak (>7 days; P < 0.01) and right P/D (P = 0.04). The multivariable analysis demonstrated that longer postoperative air leak (>7 days) remained a risk factor for RTS (odds ratio 2.5, 95% confidence interval: 1.3-4.9, P < 0.01).

CONCLUSIONS

RTS was a postoperative event that frequently observed in patients undergoing P/D. Overall, the current study findings suggest longer postoperative air leak (>7 days) as a significant risk factor for RTS.

Incidence and Risk Factors of Chest Wall Metastasis at Biopsy Sites in Patients with Malignant Pleural Mesothelioma

To investigate the incidence and risk factors of chest wall metastasis (CWM) at biopsy sites in patients with malignant pleural mesothelioma (MPM). This retrospective cohort study was conducted in 262 consecutive MPM patients who underwent multimodal treatment in which including neoadjuvant chemotherapy (NAC) and curative-intent surgery, from August 2009 to March 2021. CWM was evaluated radiologically (r-CWM) and pathologically (p-CWM). We also investigated the risk factors of p-CWM and the consistency between r-CWM and p-CWM. Of 262 patients, 25 patients were excluded from analysis due to missing data or impossibility of evaluation. Of the eligible 237 patients, pleural biopsy was performed via video-assisted thoracoscopic surgery in 197 (83.1%) and medical thoracoscopy in 40 (16.9%). Pleurodesis was performed after pleural biopsy in 74 patients (31.2%). All patients received NAC followed by curative-intent surgery. Radiological examination showed r-CWM in 43 patients (18.1%), while pathological examination showed p-CWM in 135 patients (57.0%). The incidence of p-CWM was significantly higher in the patients who received pleurodesis after pleural biopsy (77.0% vs. 47.9%, <0.001). Multivariate logistic regression analysis for p-CWM revealed that pleurodesis is an independent risk factor of p-CWM (adjusted hazard ratio, 3.46; 95% confidence interval, 1.84−6.52, <0.001). CWM at the biopsy site was pathologically proven in more than half of the patients (57.0%) who received NAC followed by curative-intent surgery, which was higher than the numbers diagnosed by radiological examinations (p-CWM: 57.0% vs. r-CWM: 18.1%). Pleurodesis after pleural biopsy is an independent risk factor of p-CWM.

Computed Tomography and Spirometry Can Predict Unresectability in Malignant Pleural Mesothelioma

Preoperative identification of unresectable pleural mesothelioma could spare unnecessary surgical intervention and accelerate the initiation of medical treatments. The aim of this study is to determine predictors of unresectability, testing our impression that the contraction of the ipsilateral hemithorax is often associated with exploratory thoracotomy. Between 1994 and 2020, 291 patients undergoing intended macroscopic complete resection for mesothelioma after chemotherapy were retrospectively investigated. Eligible patients (n = 58) presented a preoperative 3 mm slice-thickness chest computed tomography without pleural effusion or hydropneumothorax. Lung volumes (segmented using a semi-automated method), modified-Response Evaluation Criteria in Solid Tumors (RECIST) measurements, and spirometries were collected after chemotherapy. Multivariable analysis was performed to determine the predictors of unresectability. An unresectable disease was found at the time of operation in 25.9% cases. By multivariable analysis, the total lung capacity (p = 0.03) and the disease burden (p = 0.02) were found to be predictors of unresectability; cut-off values were <77.5% and >120.5 mm, respectively. Lung volumes were not confirmed to be associated with unresectability at multivariable analysis, probably due to the correlation with the disease burden (p < 0.001; r = −0.4). Our study suggests that disease burden and total lung capacity could predict MPM unresectability, helping surgeons in recommending surgery or not in a multimodality setting.

Outcomes of Conversion to Extrapleural Pneumonectomy From Pleurectomy/Decortication for Malignant Pleural Mesothelioma

In recent years, there has been a shift from extrapleural pneumonectomy (EPP) toward pleurectomy/decortication (P/D) as the preferred surgical technique. However, we occasionally encounter difficult cases wherein visceral pleurectomy requires conversion to EPP from P/D. We sought to clarify the preoperative risk factors and clinical outcomes associated with conversion to EPP. We compared and analyzed conversion to EPP and P/D between September 2012 and December 2019. Conversion to EPP was decided in case of diffuse tumor invasion to the pulmonary parenchyma or due to failure of decortication. Univariable regression analysis was performed to determine the association of preoperative variables with conversion to EPP. Survival was analyzed by the Kaplan-Meier method and log-rank test. Of the 181 patients who underwent intended P/D, 145 (80.1%) patients underwent P/D and 18 (9.9%) patients underwent conversion to EPP. The sum of 3-level pleural thickness (P < 0.001), maximum of 3-level pleural thickness (P = 0.006), and clinical T stage (P < 0.001) demonstrated association with conversion to EPP. Overall survival and progression-free survival were significantly worse in the conversion to EPP group (median overall survival, 29.2 months vs 57.0 months [P = 0.008]; median progression-free survival, 15.3 months vs 23.2 months [P = 0.005]. Our data show that approximately 1 of every 10 patients with P/D intention converted to EPP. Preoperative pleural thickness and clinical T stage may be risk factors associated with conversion to EPP. The survival rate of conversion to EPP was worse than that of P/D.

Three tumor markers for improved efficacy in the management of patients with malignant pleural mesothelioma

Background

Evaluation of tumor markers may facilitate follow-up of malignant pleural mesothelioma (MPM). We aimed was to evaluate the value of tumor markers for monitoring and predicting recurrence in patients with MPM.

Methods

In total, 152 patients who underwent curative-intent surgery after induction chemotherapy for MPM between July 2004 and December 2017 were retrospectively reviewed. Preoperative and postoperative (≤3 months after surgery) levels of soluble mesothelin-related peptide (SMRP), cytokeratin 19 fragment (Cyfra21-1), and tissue polypeptide antigen (TPA) and rates of recurrence and non-recurrence were evaluated. Factors associated with recurrence-free survival (RFS) were assessed using the Kaplan-Meier method and Cox proportional hazards model.

Results

Of the 152 patients, the positive rates of preoperative SMRP, Cyfra21-1, and TPA, levels were 26.7%, 8.6%, 9.6%, respectively; the respective postoperative levels were 4.0%, 6.3%, and 6.5%; the respective levels in patients with recurrence were 39.3%, 31.4%, 28.6%; the respective levels in patients with no recurrence were 3.7%, 0.0%, 3.8%. Nearly half (45.2%) of the patients with recurrence exhibited an increase in one or more tumor marker levels. Multivariate analysis revealed that the preoperative positive rates of one or more of the three tumor markers (hazard ratio: 1.8, 95% confidence interval: 1.1–2.8; P=0.02) were independent significant predictors of recurrence.

Conclusions

The positive rates of SMRP, Cyfra21-1, and TPA in recurrence-free patients were extremely low, with high specificity. Preoperative levels of SMRP, Cyfra21-1, and TPA, which identified patients with a high risk for recurrence, could improve management of patients with MPM.

Complications and Predictive Factors for Air Leak > 10 Days with Neoadjuvant Chemotherapy Followed by Pleurectomy/Decortication for Malignant Pleural Mesothelioma

BACKGROUND

A few studies have reported the incidence and clinical implications of complications after pleurectomy/decortication (P/D).

OBJECTIVE

The aim of this study was to assess the details of complications and predictive factors of particularly durable air leak with P/D.

METHODS

Data on 163 consecutive patients who underwent neoadjuvant chemotherapy (NAC) followed by P/D for malignant pleural mesothelioma between September 2012 and May 2020 at our institution were retrospectively analyzed. Postoperative complications and the significance of various preoperative risk factors for air leak > 10 days (AL10) to identify the group having a higher risk for particularly durable air leak were investigated. Risk factors for AL10 were sought using univariate and multivariate analyses.

RESULTS

Of 163 patients, 30- and 90-day mortality was 0.6% and 2.5%, respectively. Eighty-four (51.4%) patients experienced grade III or worse postoperative complications according to the Clavien-Dindo classification. The median duration of air leak was 7 postoperative days. AL10 occurred in 53 (32.5%) patients. Fifty-eight patients (35.6%) underwent pleurodesis and five patients (3.1%) underwent reoperation to control the air leak. On univariate analysis, performance status (PS; p = 0.003), prognostic nutritional index (p = 0.01), and pleural effusion (p = 0.04) were statistically significant risk factors for AL10, while on multivariate analysis, PS (odds ratio 4.0, 95% confidence interval 1.3-12.7; p = 0.02) remained the only variable predicted for AL10.

CONCLUSIONS

Recent postoperative mortality rates in NAC followed by P/D are quite acceptable. Approximately one in every three patients experienced AL10, and PS may be a risk factor associated with AL10.

Initial evaluation of nivolumab in patients with post-operative recurrence of malignant pleural mesothelioma

BACKGROUND

Limited options exist for treating post-recurrence patients with malignant pleural mesothelioma (MPM). This study aimed to evaluate the efficacy and feasibility of nivolumab in patients with post-operative recurrence of MPM in a real-world setting.

METHODS

This study included 35 patients with post-operative recurrence of MPM. Treatment consisted of 240-mg intravenous nivolumab administration every 2 weeks until progressive disease (PD) or serious adverse events (AEs). Additional post-treatment data were evaluated, including objective response rate (ORR), disease control rate (DCR), progression-free survival (PFS), post-treatment survival and AEs. Tumor response was assessed using the modified Response Evaluation Criteria in Solid Tumors. Survival analysis was performed using the Kaplan-Meier method. The feasibility analysis including AEs was performed with the National Cancer Institute Common Terminology Criteria for Adverse Events version 5.0.

RESULTS

Of the 35 patients who received nivolumab, median follow-up was 6 months. The median treatment duration was 3 months (range: 1-14 months), and median of 8 cycles (range: 2-32 cycles) was administered. Best overall responses were follows: 1 patient had complete response, 6 had partial response, 18 had stable disease and 8 had PD. The ORR was 20.0%, and the DCR was 77.1%. The median overall survival and PFS were 13.1 and 4.4 months, respectively. There were grade-3 AEs in four patients (11.4%). No grade-4 or -5 AEs were observed.

CONCLUSION

Nivolumab treatment in patients with post-operative recurrence of MPM seems safe and clinical efficacy.

Clinicopathological features of radiological early malignant pleural mesothelioma with no apparent tumor or pleural thickening

BACKGROUND

We occasionally encounter malignant pleural mesothelioma (MPM) of no apparent tumor or pleural thickening that is radiological early MPM. This study aimed to examine the clinicopathological outcomes of radiological early MPM.

METHODS

Patients with MPM treated with neoadjuvant chemotherapy and planned surgery at the time of diagnosis between July 2004 and December 2019 were retrospectively examined. Pretreatment maximal pleural thickness of all patients was measured on chest computed tomography. We extracted and investigated the patients who exhibited a lack of pleural thickening or visible tumor, which was defined as radiological early MPM. Survival was analyzed by the Kaplan-Meier method.

RESULTS

Of 296treated patients, 16 (5.4%) exhibited radiological early MPM. Fourteen (87.5%) of these patients underwent pleurectomy/decortication and 2 (12.5%) underwent extrapleural pneumonectomy. Pathological stage T1 disease was diagnosed in 14 (87.5%) patients; 2 (12.5%) exhibited pulmonary parenchymal invasion (pathological stage T2). Lymphatic invasion was detected in only 1 patient. Lymph node metastases and vascular invasion were not detected. Median follow-up was 42 months. Median progression-free survival and median overall survival were 40.7 and 56.1 months, respectively. The 3-year progression-free survival and overall survival rates were 84.8% and 83.6%, respectively.

CONCLUSIONS

Radiological early MPM occurs in approximately 1 of every 20 patients treated with neoadjuvant chemotherapy and surgery planned at the time of diagnosis in an experienced center. Radiological early MPM was associated with early pathological stage and long-term survival.

The timing of chemotherapy in the management plan for medically operable early-stage malignant pleural mesothelioma

Introduction: Trimodality therapy (including surgery, chemotherapy and radiation therapy) represents an important management approach of early-stage malignant pleural mesothelioma (MPM). The oncological value, as well as the proper sequence of the three modalities, is still under investigations. Areas Covered: The article covers the timing of chemotherapy in the management plan with either a neoadjuvant approach or adjuvant approach. It evaluates also how to select patients for induction chemotherapy and how to assess the response to treatment. Expert Opinion: Management of patients with early-stage MPM must be completed in a multidisciplinary team in tertiary centers. Availability of newer prognostic and response assessment tools should facilitate the use of induction chemotherapy as well as the selection of patients who might benefit from radical surgery.