Trimodality Treatment of Malignant Pleural Mesothelioma: An Institutional Review.
OBJECTIVE
Malignant pleural mesothelioma (MPM) is a deadly disease with varying treatment options. This study retrospectively describes treatment practices at the University of Washington Medical System from 1980 to 2011, and evaluates the impact of trimodality therapy and radiation (photon and neutron) on survival.


METHODS
A retrospective study was conducted on patients treated for MPM. Univariate and multivariate methods were utilized to evaluate potential factors associated with survival. Treatments received and baseline characteristics were included. Survival analysis of trimodality therapy was performed using a propensity score method to control for baseline characteristics.


RESULTS
Among 78 eligible patients, the median age at diagnosis was 59 years and the median survival was 13.7 months. On multivariate analysis, the significant predictors of improved survival were age, smoking history, location, and receipt of radiation therapy or chemotherapy. In the 48 patients receiving radiation therapy, the difference in survival between neutron therapy and non-neutron therapy patients was not statistically significant: hazard ratio, 1.20 (95% confidence interval, 0.68-2.13), P=0.52. Patients receiving trimodality therapy were more likely to have early-stage disease (60% vs. 30%) and epithelioid histology (86% vs. 58%). In a propensity score-weighted Cox proportional hazards model, trimodality therapy patients had improved overall survival, hazard ratio 0.45, P=0.004, median 14.6 versus 8.6 months.


CONCLUSIONS
Trimodality therapy was significantly associated with prolonged survival in patients with MPM, even when adjusting for baseline patient factors. Radiation therapy was associated with improved survival, but the modality of radiation therapy used was not associated with outcome.
Department of Radiation Oncology, University of Washington Medical Center, Seattle, WA.
Matthew
M
Kapeles
Department of Radiation Oncology, University of Washington Medical Center, Seattle, WA.
Michael F
MF
Gensheimer
Department of Medicine, Oregon Health and Science University, Portland.
Dylan A
DA
Mart
Department of Radiation Oncology, University of Washington Medical Center, Seattle, WA.
Theo L
TL
Sottero
Department of Radiation Oncology, University of Washington Medical Center, Seattle, WA.
Aaron S
AS
Kusano
Bellevue Ear, Nose & Throat, Bellevue, WA.
Anh
A
Truong
Department of Radiation Oncology, University of Washington Medical Center, Seattle, WA.
Farhood
F
Farjah
Department of Radiation Oncology, University of Washington Medical Center, Seattle, WA.
George E
GE
Laramore
Celilo Radiation Therapy, Mid-Columbia Medical Center, The Dalles, OR.
Keith J
KJ
Stelzer
Department of Radiation Oncology, University of Washington Medical Center, Seattle, WA.
Shilpen A
SA
Patel
D000328:Adult; D000367:Age Factors; D000368:Aged; D000704:Analysis of Variance; D017024:Chemotherapy, Adjuvant; D015331:Cohort Studies; D003131:Combined Modality Therapy / Q000379:methods; D016208:Databases, Factual; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000401:mortality* / Q000473:pathology / Q000628:therapy*; D008297:Male; D008654:Mesothelioma / Q000401:mortality* / Q000473:pathology / Q000628:therapy*; D000086002:Mesothelioma, Malignant; D008875:Middle Aged; D015999:Multivariate Analysis; D009361:Neoplasm Invasiveness / Q000473:pathology; D009367:Neoplasm Staging; D010994:Pleura / Q000601:surgery*; D010997:Pleural Neoplasms / Q000401:mortality* / Q000473:pathology / Q000628:therapy*; D011379:Prognosis; D057216:Propensity Score; D016016:Proportional Hazards Models; D018714:Radiotherapy, Adjuvant; D012189:Retrospective Studies; D018570:Risk Assessment; D012737:Sex Factors; D016019:Survival Analysis