Influence of Radiotherapy Technique and Dose on Patterns of Failure for Mesothelioma Patients After Extrapleural Pneumonectomy

Purpose: Extrapleural pneumonectomy (EPP) is an effective treatment of malignant pleural mesothelioma. We compared the outcomes after moderate-dose hemithoracic radiotherapy (MDRT) and high-dose hemithoracic RT (HDRT) after EPP for malignant pleural mesothelioma. Methods and Materials: Between July 1994 and April 2004, 39 patients underwent EPP and adjuvant RT at Dana-Farber Cancer Institute/Brigham and Women's Hospital. Between 1994 and 2002, MDRT, including 30 Gy to the hemithorax, 40 Gy to the mediastinum, and boosts to positive margins or nodes to 54 Gy, was given, generally with concurrent chemotherapy. In 2003, HDRT to 54 Gy with a matched photon/electron technique was given, with sequential chemotherapy. Results: A total of 39 patients underwent RT after EPP. The median age was 59 years (range, 44-77). The histologic type was epithelial in 25 patients (64%) and mixed or sarcomatoid in 14 patients (36%). Of the 39 patients, 24 underwent MDRT and 15 (39%) HDRT. The median follow-up was 23 months (range, 6-71). The median overall survival was 19 months (95% confidence interval, 14-24). The median time to distant failure (DF) and local failure (LF) was 20 months (95% confidence interval, 14-26) and 26 months (95% confidence interval, 16-36), respectively. On univariate and multivariate analyses, only a mixed histologic type was predictive of inferior DF (p <0.006) and overall survival (p <0.004). The RT technique was not predictive of LF, DF, or overall survival. The LF rate was 50% (12 of 24) after MDRT and 27% (4 of 15) after HDRT (p = NS). Four patients who had undergone HDRT were alive and without evidence of disease at the last follow-up. Conclusions: High-dose hemithoracic RT appears to limit in-field LF compared with MDRT. However, DF remains a significant challenge, with one-half of our patients experiencing DF.