Surgical assessment of malignant pleural mesothelioma: have we reached a critical stage?

Quantitative Clinical Staging for Patients With Malignant Pleural Mesothelioma

Background

Analysis of the International Association for the Study of Lung Cancer (IASLC) Malignant Pleural Mesothelioma (MPM) database revealed that clinical (cTNM) staging minimally stratified survival and was discrepant with pathological (pTNM) staging. To improve prognostic classification of MPM, alternative staging models based on quantitative parameters were explored.

Methods

An institutional review board–approved MPM registry was queried to identify patients with available pathological and preoperative imaging data. Qualifying patients were randomly assigned to training and test sets in a 1:2 ratio. Computed cTNM and pTNM staging (AJCC Cancer Staging Manual, 7th ed.) were compared. Quantitative image analysis included tumor volume assessed from three-dimensional reconstruction of computed tomography scans (VolCT) and maximal fissural thickness (Fmax). Survival was estimated using the Kaplan-Meier method, and the relationship with VolCT was examined by Cox regression analysis to identify optimized cut-points. Performance of cTNM and quantitative models derived was compared in the test set using Harrell’s C index.

Results

A total of 472 patients met inclusion criteria. TNM staging was concordant with pathological TNM staging in 171 of 472 (36.2%), understaged in 209 (44.2%), and overstaged in 92 (19.4%) patients. The most concordant feature was involvement of interlobar fissures. A quantitative clinical staging model comprising VolCT and Fmax (c-index = 0.638, 95% confidence interval [CI] = 0.603 to 0.673) performed statistically significantly better as a prognostic classifier when compared in the test set with cTNM (c-index = 0.562, 95% CI = 0.525 to 0.599, P = .001).

Conclusions

Improved prognostic performance may be achievable by quantitative clinical staging combining VolCT and Fmax, providing a cost-effective and clinically relevant surrogate for clinical TNM stage.

Hyperthermic Intrathoracic Chemotherapy (HITHOC) for Pleural Malignancies-Experience from Indian Centers

Hyperthermic intrathoracic chemotherapy (HITHOC) has been used in addition to radical surgery for primary and secondary pleural malignancies to improve local control, prolong survival, and improve the quality of life. This study was performed to study the indications, methodology, perioperative outcomes, and survival in patients undergoing HITHOC at Indian centers. A retrospective analysis of prospectively collected demographic and clinical data, perioperative and survival data of patients undergoing surgery with or without HITHOC was performed. From January 2011 to May 2018, seven patients underwent pleurectomy/decortication (P/D) or extrapleural pneumonectomy (EPP) with HITHOC and four had P/D or EPP alone at three Indian centers. P/D was performed in two and EPP in nine patients. The primary tumor was pleural mesothelioma in eight, metastases from thymoma in one, germ cell tumor in one, and solitary fibrous tumor of the pleura in one. HITHOC was performed using cisplatin. Grade 3-4 complications were seen in one patient in the HITHOC group and none in the non-HITHOC group, and one patient in the non-HITHOC group died of complications. At a median follow-up of 9 months, five patients of the HITHOC group were alive, four without recurrence, and one with recurrence. One patient in the non-HITHOC group was alive and disease-free at 24 months, and two died of progression at 18 and 36 months. HITHOC can be performed without increasing the morbidity of P/D or EPP. Most of these patients require multimodality treatment and are best managed by multidisciplinary teams.

New Concepts in the Treatment of Malignant Pleural Mesothelioma

Malignant pleural mesothelioma (MPM) is a highly aggressive and generally incurable cancer. Current anti-MPM chemotherapy-based treatments are only marginally effective, and long-term survival remains an unmet goal. Nonetheless, in selected cases, personalized surgery-based multimodality treatments (MMT) have been shown to significantly extend survival. The design of MMT and selection of patients are challenging, and optimal results require accurate presurgical diagnosis, staging, and risk stratification. Further, meticulous surgical techniques and advanced radiation protocols must be applied. We review key principles and evolving concepts in the care of MPM patients with a focus on the expanding role of MMT in MPM.

Malignant pleural mesothelioma: predictors and staging

Malignant pleural mesothelioma remains a rapidly fatal cancer with few effective therapies. Unusual anatomic features complicate determination of stage and prognosis for individual patients. Validation of staging criteria has been difficult given the rarity of the disease and the fact that only a minority of patients undergo surgical resection with pathological examination of their tumors. Thus, additional heuristic factors and algorithms have been taken into account by clinicians to estimate prognosis and inform discussion of appropriate management strategies or clinical research protocols with patients.

Role of thoracoscopy, mediastinoscopy and laparoscopy in the diagnosis and staging of malignant pleural mesothelioma

Malignant pleural mesothelioma (MPM) is an aggressive malignancy with dismal prognosis. Unfortunately, chemotherapy only marginally extends patient survival and palliative care often remains the sole therapeutic option. Nonetheless, for a selected group of patients that present with an early disease stage and an epithelioid histology, a personally tailored multimodality therapeutic (MMT) protocol comprising of cyto-reductive surgery and chemotherapy with or without radiation therapy may significantly prolong survival. Accurately selecting patients for this aggressive therapeutic approach is challenging and is based in part on optimal pre-surgical staging. Here we discuss the role of thoracoscopy, mediastinoscopy and laparoscopy in the diagnosis and staging of MPM patients prior to definite surgical resection.

Impact of Age on Long-Term Outcomes of Surgery for Malignant Pleural Mesothelioma

BACKGROUND

Although malignant pleural mesothelioma (MPM) is generally a disease associated with more advanced age, the association of age, treatment, and outcomes has not been well-characterized. We evaluated the impact of age on outcomes in patients with MPM to provide data for use in the treatment selection process for elderly patients with potentially resectable disease.

PATIENTS AND METHODS

Overall survival (OS) of patients younger than 70 and 70 years or older with Stage I to III MPM who underwent cancer-directed surgery or nonoperative management in the Surveillance, Epidemiology, and End Results database (2004-2010) was evaluated using multivariable Cox proportional hazard models and propensity score-matched analysis.

RESULTS

Cancer-directed surgery was used in 284 of 879 (32%) patients who met inclusion criteria, and was associated with improved OS in multivariable analysis (hazard ratio, 0.71; P = .001). Cancer-directed surgery was used much less commonly in patients 70 years and older compared with patients younger than 70 years (22% [109/497] vs. 46% [175/382]; P < .001), but patients 70 years and older had improved 1-year (59.4% vs. 37.9%) and 3-year (15.4% vs. 8.0%) OS compared with nonoperative management. The benefit of surgery in patients 70 years and older was observed even after propensity score-matched analysis was used to control for selection bias.

CONCLUSION

Surgical treatment is associated with improved survival compared with nonoperative management for both patients younger than 70 years and patients aged 70 years or older.

Malignant pleural mesothelioma signs and symptoms

Malignant pleural mesothelioma (MPM) is developed from mesothelial cells and its behavior depends on the degree of pleural invasion and adjacent organs. This extension around the pleural cavity or more unlikely located on a limited area leads to clinical signs as dyspnea, shortness of breath, cough or chest pain. The relationship between asbestos exposure and MPM has been well established. The symptoms of MPM usually appear 30–40 years after exposure to asbestos. Consequently, patients are unaware that the clinical presentation is related to their clinical exposure which happened much earlier in their lives. Clinical manifestations of MPM are usually nonspecific and should not be used alone as diagnostic criteria, even in case of previous asbestos exposure as recommended by the ERS guidelines.

Impact of mesothelioma histologic subtype on outcomes in the Surveillance, Epidemiology, and End Results database

BACKGROUND

This study was conducted to determine how malignant pleural mesothelioma (MPM) histology was associated with the use of surgery and survival.

METHODS

Overall survival of patients with stage I-III epithelioid, sarcomatoid, and biphasic MPM in the Surveillance, Epidemiology, and End Results database from 2004-2010 was evaluated using multivariate Cox proportional hazards models.

RESULTS

Of 1183 patients who met inclusion criteria, histologic subtype was epithelioid in 811 patients (69%), biphasic in 148 patients (12%), and sarcomatoid in 224 patients (19%). Median survival was 14 mo in the epithelioid group, 10 mo in the biphasic group, and 4 mo in the sarcomatoid group (P < 0.01). Cancer-directed surgery was used more often in patients with epithelioid (37%, 299/811) and biphasic (44%, 65/148) histologies as compared with patients with sarcomatoid histology (26%, 58/224; P < 0.01). Among patients who underwent surgery, median survival was 19 mo in the epithelioid group, 12 mo in the biphasic group, and 4 mo in the sarcomatoid group (P < 0.01). In multivariate analysis, surgery was associated with improved survival in the epithelioid group (hazard ratio [HR] 0.72; P < 0.01) but not in biphasic (HR 0.73; P = 0.19) or sarcomatoid (HR 0.79; P = 0.18) groups.

CONCLUSIONS

Cancer-directed surgery is associated with significantly improved survival for MPM patients with epithelioid histology, but patients with sarcomatoid and biphasic histologies have poor prognoses that may not be favored by operative treatment. The specific histology should be identified before treatment, so that surgery can be offered to patients with epithelioid histology, as these patients are most likely to benefit.

Do we need a revised staging system for malignant pleural mesothelioma? Analysis of the IASLC database

INTRODUCTION

A number of staging systems have been proposed for malignant pleural mesothelioma (MPM) in the past, but few have utilized a TNM (tumor, node, metastasis) system. The International Association for the Study of Lung Cancer (IASLC) and the International Mesothelioma Interest Group (IMIG) previously developed a TNM-staging system which has been accepted by the International Union Against Cancer (UICC) and the American Joint Commission on Cancer (AJCC). The present study examines this staging system by analysing the updated IASLC database for patients with MPM.

METHODS

De-identified data from participating centres dated from 1995 to 2009 were submitted to the IASLC Statistical Center. Surgical procedures included those with a curative or palliative intent. Survival was measured from the date of pathologic diagnosis to the most recent contact or death. Endpoints included overall survival and analysis of potential prognostic factors.

RESULTS

Data was available for 3,101 patients from 15 centers, mostly from North America and Europe. After a median follow-up of 15 months, a number of clinicopathological and treatment-related prognostic factors were found to significantly influence overall survival. These included overall tumor stage based on the proposed TNM staging system, T category, N category, tumor histology, gender, age, and type of operation.

CONCLUSIONS

The IASLC database represents the largest, multicenter and international database on MPM to date. Analyses demonstrate that the proposed TNM staging system effectively distinguishes the T and N categories, but also highlight areas for potential revision in the future.

Hyperthermic intraoperative pleural cisplatin chemotherapy extends interval to recurrence and survival among low-risk patients with malignant pleural mesothelioma undergoing surgical macroscopic complete resection

OBJECTIVE

Local recurrence limits long-term survival in patients with malignant pleural mesothelioma. We investigated whether hyperthermic intraoperative cisplatin chemotherapy lavage affects the interval to recurrence and overall survival among patients with favorable prognostic factors.

METHODS

Using a preoperative risk assessment algorithm we had previously developed and validated, we retrospectively identified a cohort of patients treated with cytoreductive surgery from 2001 to 2009. The patients had epithelial histologic findings on biopsy and were characterized as having a low risk of early recurrence and death (ie, tumor volume ≤ 500 cm(3) and were either men with a hemoglobin level of ≥ 13 g/dL or were women). Those patients who had received hyperthermic intraoperative cisplatin chemotherapy were compared with a comparison group of those who had not. Fisher's exact test was used to determine the balance of prognostic factors. The Kaplan-Meier method and log-rank tests were used to estimate and compare the interval to recurrence and overall survival. Cox proportional hazards regression was used for multivariate analysis.

RESULTS

The cohort criteria identified 103 patients: 72 who received hyperthermic intraoperative cisplatin chemotherapy and 31 who did not. The groups were balanced for prognostic factors, except for the use of neoadjuvant chemotherapy (more common in the comparison group). The hyperthermic intraoperative cisplatin chemotherapy group exhibited a significantly longer interval to recurrence (27.1 vs 12.8 months) and overall survival (35.3 vs 22.8 months) than the comparison group. The improved interval to recurrence and overall survival for the hyperthermic intraoperative cisplatin chemotherapy group were particularly evident among the subgroups of patients who had not received hemithoracic radiotherapy and who had pathologic stage N1 or N2 lymph node metastases.

CONCLUSIONS

A favorable outcome and minimal incremental morbidity support the incorporation of hyperthermic intraoperative cisplatin chemotherapy into multimodality treatment strategies for patients with low-risk epithelial malignant pleural mesothelioma.

Epithelial malignant pleural mesothelioma after extrapleural pneumonectomy: stratification of survival with CT-derived tumor volume

OBJECTIVE

The purpose of this study was to assess the usefulness of CT-derived tumor volume, with control for other prognostic factors, for stratifying survival after surgery-based multimodality treatment of a large cohort of patients with epithelial malignant pleural mesothelioma.

MATERIALS AND METHODS

We retrospectively reviewed 338 patients with mesothelioma who underwent extrapleural pneumonectomy between 2001 and 2007. The study cohort comprised 88 patients with epithelial subtype tumors, DICOM-format CT scans, and data regarding neoadjuvant and adjuvant therapy. Tumor volume was calculated, and Kaplan-Meier survival and Cox regression analyses were performed to compare the estimated survival functions of patient subgroups based on volume and other covariates related to outcome (sex, age, preoperative platelet count, hemoglobin concentration, WBC count, clinical and pathologic TNM category, and administration of neoadjuvant and adjuvant therapy). A multivariate regression model was derived on the basis of the most significant univariate predictors.

RESULTS

The median estimated tumor volume was 319 cm(3) (range, 4-3256 cm(3)). In univariate analysis, tumor volume, hemoglobin concentration, platelet count, pathologic TNM category, and administration of adjuvant chemotherapy or radiation therapy met the criteria for inclusion in the reverse stepwise regression analysis. In the final model, tumor volume, hemoglobin concentration, and administration of adjuvant chemotherapy or radiotherapy were identified as independently associated with overall survival.

CONCLUSION

With control of prognostic covariates, CT-derived tumor volume can be used to stratify survival of patients with epithelial mesothelioma after extrapleural pneumonectomy and should be included in prognostic evaluation of patients for whom resection is being considered.

The new case for cervical mediastinoscopy in selection for radical surgery for malignant pleural mesothelioma

OBJECTIVES

Selection criteria for radical surgery in malignant pleural mesothelioma (MPM) and related clinical trials remain controversial. The relative importance of nodal metastases and the need for pre-operative nodal staging are undetermined.

METHODS

From a prospective database, we identified 212 patients with non-sarcomatoid MPM (160 epithelioid and 52 biphasic). A total of 127 patients underwent extrapleural pneumonectoctomy (EPP) and 85 lung-sparing total pleurectomy (LSTP) with lymphadenectomy. We investigated the effect of nodal burden and distribution in survival by testing for differences between N0, N1 and N2 disease and constructing a theoretical model dividing the patients into four groups according to diseased nodes identified in the surgical specimen: Group 0, no nodal disease; Group CM, nodes accessible by cervical mediastinoscopy (CM): Stations 2, 3a, 4 and 7; Group EBUS/EUS, nodes accessible by endobronchial (EBUS) or endoscopic (EUS) ultrasound: Stations 2, 3a, 4 and 7-11. Group EM, extramediastinal nodes not accessible by CM or EBUS/EUS: Stations 5, 6, internal mammary, pericardial and diaphragmatic lymph nodes.

RESULTS

There was no difference in overall median survival between EPP and LSTP [15.6, SE 1.8, 95% confidence interval (CI) 12-19 months versus 13.4, SE 2.3, 95% CI 9-18 months, P=0.41]. Patients with N0 disease (n=94) had the best prognosis: median survival was 19.6 months (SE 3, 95% CI 13.2-26) versus 12 months for the 19 patients with N1 (SE 1.5, 95% CI 9-15) and 13.6 months for 99 patients with N2 (SE 1.7, 95% CI 10-17), P=0.015. Subgroup analysis of patients with nodal metastases revealed no significant survival difference between group CM and group EBUS/EUS: achieving maximum theoretical diagnostic yield CM could detect 63 (54%) of patients with nodal disease and the median survival of this group was 13.6 months (SE 2, 95% CI 9.6-17.6). EBUS/EUS could detect an additional 30 cases (26%) with survival of 11.3 months (SE 1, 95% CI 9-13.6). The survival in group EM (25 cases, 21%, median survival 18.7 months, SE 6, 95% CI 7-30) was significantly better than groups CM or EBUS/EUS, P=0.002.

CONCLUSIONS

There is a strong case for routine CM as a method of prognostic staging in all patients undergoing radical surgery for MPM. The addition of EUS staging and the detection of nodal metastases inaccessible to mediastinoscopy had no prognostic benefit.

Long-term survival after lung-sparing total pleurectomy for locally advanced (International Mesothelioma Interest Group Stage T3-T4) non-sarcomatoid malignant pleural mesothelioma

OBJECTIVES

There is a body of opinion that advocates extrapleural pneumonectomy (EPP) as the only radical treatment option for locally advanced (T3/T4) malignant pleural mesothelioma (MPM). We tested the hypothesis that lung-sparing total pleurectomy (LSTP) can be as effective as EPP in locally advanced MPM with reduced risk.

METHODS

We analysed prospective data on 165 patients (128 with epithelioid and 37 with biphasic MPM) with pT3 (n = 108) and pT4 (n = 57) tumours. Ninety-eight (59.4%) of the patients underwent EPP and 67 (40.6%) LSTP. We compared intergroup differences in: length of stay (LOS), post-operative complications, survival, pattern of disease progression and disease-free interval (DFI).

RESULTS

There were significantly more complications after EPP: 67 (68%) vs. 29 (43%) in LSTP, P = 0.002. Thirty-day mortality was 7% for EPP and 3% for LSTP (P = 0.31). LOS was similar (mean 19 days for EPP, 15 days for LSTP, P = 0.19). We noted only minor differences in the initial site of disease progression. In 33 (41%) of EPP patients, disease progressed locally compared with 22 (44%) after LSTP. Seventeen patients post-EPP (21%) had distal progression compared with only three (6%) post-LSTP and synchronous distal and local recurrence was similar: 15 (19%) post-EPP vs. 12% for LSTP (P = 0.11). There was no significant intergroup difference in median survival: EPP 14.7 months (SE 1.3, 95% CI 12.2-17.2) vs. LSTP 13.4 months (SE 1.9, 95% CI 9.7-17.1), P = 0.91, nor in DFI: EPP 10.7 months (SE 0.8, 95% CI 9-12) vs. LSTP 16 months (SE 1, 95% CI 9-22). In chemonaive patients (n = 124), adjuvant chemotherapy was received by significantly more patients after LSTP (32/53 LSTP vs. 26/71 EPP patients, P = 0.011). Estimated 1-5 years survival for EPP was 58, 30, 11, 9 and 6% and for LSTP 52, 28, 20, 13 and 4%.

CONCLUSIONS

In disagreement with standard opinion, we advocate LSTP as the procedure of choice in locally advanced MPM: it offers at least equally as good oncological results as EPP in this group of patients with reduced early complications. Despite a tendency for increased local recurrence in the LSTP group, overall survival is not compromised.