Prevalence of in vitro chemotherapeutic drug resistance in primary malignant pleural mesothelioma: Result in a cohort of 203 resection specimens
Received 29 May 2009; received in revised form 19 October 2009; accepted 14 November 2009. published online 31 May 2010.
Objective
Optimizing the multimodality treatment of malignant pleural mesothelioma depends on many factors including an adequate chemotherapeutic response. Currently, chemotherapy regimens for patients with mesothelioma are empirically selected. In vitro chemotherapy resistance in human mesothelioma has not been reported. Our goal was to determine the prevalence of drug resistance in a large sample of malignant pleural mesothelioma using a commercially available assay.
Methods
Tumors specimens (n = 203) were cultured for analysis of chemoresistance using the extreme drug resistance assay. Evaluable results were obtained in 168 (168/203 = 83%) specimens. Each specimen was tested with 3 drugs: cisplatin, gemcitabine, and vinorelbine. Drug resistance was characterized as low, intermediate, or extreme. Median age was 64 years (30–85 years). Forty-four (26%) patients received neoadjuvant chemotherapy before sampling and testing. The distribution of histopathologic cell types was epithelial (103; 61%), mixed (57; 34%), and sarcomatoid (8; 5%).
Results
A significant proportion of tumors had extreme/intermediate drug resistance to cisplatin (27%), gemcitabine (31%), or vinorelbine (59%). Nineteen tumors (11%) had extreme/intermediate resistance to all 3 drugs. Resistance (extreme/intermediate) to cisplatin was more prevalent in epithelial tumors than in nonepithelial (33% vs 18%; P = .0394). No significant differences in chemoresistance were found in tumors of patients who had received neoadjuvant chemotherapy compared with those who had not.
Conclusions
The feasibility of performing off-site in vitro drug resistance assays on resected malignant mesothelioma specimens is reported. A significant proportion of mesothelioma tumors exhibited extreme/intermediate resistance to cisplatin, gemcitabine, or vinorelbine.
Division of Thoracic Surgery, Department of Surgery, Brigham and Women's Hospital, Boston, Mass
Address for reprints: Tamara Raveh Tilleman, MD, PhD, Medical Director Clinical Research, Division of Thoracic Surgery, Brigham and Women's Hospital, 15 Francis St, Boston, MA 02115.
ABSTRACT