The influence of radiotherapy technique and dose on the patterns of failure for mesothelioma patients following extrapleural pneumonectomy

Abstract

7094 Background: Extrapleural pneumonectomy (EPP) is an effective treatment of pleural mesothelioma(MPM). We present a comparison of moderate-dose hemithoracic radiation (MDRT) to high-dose hemithoracic radiation (HDRT) following EPP for MPM. Methods: From 7/94 to 4/04, 39 pts underwent EPP and adjuvant radiotherapy (RT) at DFCI/BWH. From 1994–2002, MDRT, 30Gy to the hemithorax with boosts to the mediastinum or chest wall to 40–54 Gy was given, generally with concurrent chemotherapy (CT). Beginning in 2003, HDRT to 54 Gy as published by Yajnik et al (IJROBP 03’) was given with sequential CT. Results: Thirty-nine pts received RT following EPP. Median age was 59 yrs (range 44–77). Histology was epithelial in 25 (64%) pts and mixed/sarcomatoid in 14 (46%) pts. Twenty-four pts were treated with MDRT. 19 pts received concurrent platinum-based CT with MDRT. Three received cyclophosphomide, adriamycin and cisplatin (CDDP) CT prior to radiotherapy and 2 did not receive CT. 14 pts (39%) were treated with HDRT. 10/14 received sequential CDDP/gemcitabine, 4 received CDDP/pemetrexed and 1 patient received intraoperative CDDP. The median follow-up was 20 mos (range, 6–73 mos). Overall survival (OS) was 19 mos (95% CI, 14–24 mos). The median times to distant failure (DF) and local recurrence (LR) were 20 mos (95% CI, 14–26 mos) and 26 mos (95% CI, 16–36 mos), respectively. No significant differences in outcome between the two radiotherapy regimens were seen. One patient died of radiation-induced liver disease, one of pneumonitis and one of an MI. Four pts who received HDRT are alive and NED. On univariate and multivariate analysis mixed histology was predictive of DF and OS (p < .006; p < .004). Neither RT technique nor type of CT were predictive of LF, DF, or OS. The patterns of failure are in the table below. Conclusions: HDRT appears to limit in field local failures as compared to MDRT. Distant failure remains a significant challenge, with half of the patients experiencing distant failure. [Table: see text] No significant financial relationships to disclose.