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Objectives: Malignant pleural mesothelioma is an aggressive and rare malignancy that frequently recurs despite aggressive therapy. We evaluated the frequency of treatment with surgery, radiation or chemotherapy, changes in therapy and survival over time and factors associated with the receipt of trimodality therapy., Methods: The National Cancer Database (NCDB) was used to query patients with histologically proven malignant pleural mesothelioma (2004-14). Treatment over time was evaluated using the Armitage trend test. Factors associated with the receipt of trimodality therapy were analysed using logistic regression., Results: Among 20 561 patients, only 4028 (20%) underwent cancer-directed surgery; 533 (2.6%) of whom received trimodality therapy. From 2004 to 2014, the use of surgery with chemotherapy increased 87% (P < 0.01), with no statistically significant change in the use of trimodality therapy. Median survival also increased from 8 months to 11 months (P < 0.01). Patients who were treated at an academic centre or who travel >26 miles for treatment were more likely to undergo trimodality therapy. Additional factors associated with the receipt of trimodality therapy include age less than 70, Charlson comorbidity score of 0 and presence of private insurance., Conclusions: Many malignant pleural mesothelioma patients are not treated with trimodality therapy, with significant variation in treatment patterns. Referrals to high-volume and specialized centres may help offer more therapeutic options and trial or registry enrolment.

Purpose Small observational studies have shown a survival advantage to undergoing cancer-directed surgery for malignant pleural mesothelioma (MPM); however, it is unclear if these results are generalizable. Our purpose was to evaluate survival after treatment of MPM with cancer-directed surgery and to explore the effect surgery interaction with chemotherapy or radiation therapy on survival by using the National Cancer Database. Patients and Methods Patients with microscopically proven MPM were identified within the National Cancer Database (2004 to 2014). Propensity score matching was performed 1:2 and among this cohort, a Cox proportional hazards regression model was used to identify predictors of survival. Median survival was calculated by using the Kaplan-Meier method. Results Of 20,561 patients with MPM, 6,645 were identified in the matched cohort, among whom 2,166 underwent no therapy, 2,015 underwent chemotherapy alone, 850 underwent cancer-directed surgery alone, 988 underwent surgery with chemotherapy, and 274 underwent trimodality therapy. The remaining 352 patients underwent another combination of surgery, radiation, or chemotherapy. Thirty-day and 90-day mortality rates were 6.3% and 15.5%. Cancer-directed surgery, chemotherapy, and radiation therapy were independently associated with improved survival (hazard ratio, 0.77, 0.74, and 0.88, respectively). Stratified analysis revealed that surgery-based multimodality therapy demonstrated an improved survival compared with surgery alone, with no significant difference between surgery-based multimodality therapies; however, the largest estimated effect was when cancer-directed surgery, chemotherapy, and radiation therapy were combined (hazard ratio, 0.52). For patients with the epithelial subtype who underwent trimodality therapy, median survival was extended from 14.5 months to 23.4 months. Conclusion MPM is an aggressive and rapidly fatal disease. Surgery-based multimodality therapy was associated with improved survival and may offer therapeutic benefit among carefully selected patients.

Purpose: Specificity protein 1 (SP1) is an oncogenic transcription factor overexpressed in various human malignancies. This study sought to examine SP1 expression in malignant pleural mesotheliomas (MPM) and ascertain the potential efficacy of targeting SP1 in these neoplasms., Experimental Design: qRT-PCR, immunoblotting, and immunohistochemical techniques were used to evaluate SP1 expression in cultured MPM cells and MPM specimens and normal mesothelial cells/pleura. MTS, chemotaxis, soft agar, β-galactosidase, and Apo-BrdUrd techniques were used to assess proliferation, migration, clonogenicity, senescence, and apoptosis in MPM cells following SP1 knockdown, p53 overexpression, or mithramycin treatment. Murine subcutaneous and intraperitoneal xenograft models were used to examine effects of mithramycin on MPM growth in vivo. Microarray, qRT-PCR, immunoblotting, and chromatin immunoprecipitation techniques were used to examine gene expression profiles mediated by mithramycin and combined SP1 knockdown/p53 overexpression and correlate these changes with SP1 and p53 levels within target gene promoters., Results: MPM cells and tumors exhibited higher SP1 mRNA and protein levels relative to control cells/tissues. SP1 knockdown significantly inhibited proliferation, migration, and clonogenicity of MPM cells. Mithramycin depleted SP1 and activated p53, dramatically inhibiting proliferation and clonogenicity of MPM cells. Intraperitoneal mithramycin significantly inhibited growth of subcutaneous MPM xenografts and completely eradicated mesothelioma carcinomatosis in 75% of mice. Mithramycin modulated genes mediating oncogene signaling, cell-cycle regulation, senescence, and apoptosis in vitro and in vivo. The growth-inhibitory effects of mithramycin in MPM cells were recapitulated by combined SP1 knockdown/p53 overexpression., Conclusions: These findings provide preclinical rationale for phase II evaluation of mithramycin in patients with mesothelioma., (©2015 American Association for Cancer Research.)