Retrospective analysis of stereotactic ablative radiotherapy (SABR) for metastatic lung lesions (MLLs) in comparison with a contemporaneous cohort of primary lung lesions (PLLs)

Feras Oskan; Yvonne Dzierma; Stefan Wagenpfeil; Christian Rübe; Jochen Fleckenstein

doi:10.21037/jtd.2017.03.07

Retrospective analysis of stereotactic ablative radiotherapy (SABR) for metastatic lung lesions (MLLs) in comparison with a contemporaneous cohort of primary lung lesions (PLLs)

J Thorac Dis. 2017 Mar;9(3):742-756. doi: 10.21037/jtd.2017.03.07.

Authors

Feras Oskan^{1

2}, Yvonne Dzierma¹, Stefan Wagenpfeil³, Christian Rübe¹, Jochen Fleckenstein¹

Affiliations

¹ Department of Radiotherapy and Radiation Oncology, Saarland University Medical Center, 66421 Homburg, Saarland, Germany.
² Department of Radiation Oncology, Alb-Fils Kliniken GmbH, Eichertstr. 3, 73035 Goeppingen, Germany.
³ Institute of Medical Biometry, Epidemiology and Medical Informatics, Saarland University, Campus Homburg, 66421 Homburg, Saarland, Germany.

Abstract

Background: The net benefit from local ablative therapy for pulmonary oligometastases remains unknown. The outcomes of stereotactic ablative radiotherapy (SABR) for metastatic lung lesions (MLLs) were analyzed retrospectively and compared with those of SABR for primary lung lesions (PLLs).

Methods: Medical records of patients treated with lung SABR between 2011 and 2014 were retrospectively reviewed. Basic patient, lesion and treatment characteristics were compared using the Pearson chi-square test for categorical and Mann-Whitney U test for continuous variables. To estimate the rates of local control (LC), progression-free survival (PFS), survival after the first progression post-SABR (SAPF) and overall survival (OS), the Kaplan-Meier method was used, and the differences between groups were assessed by means of the log rank test. The uni- and multivariate Cox proportional hazards regression model was used to identify predictive factors for these endpoints.

Results: Twenty-nine MLLs in 18 consecutive patients and 51 PLLs in 42 patients were treated stereotactically and included in the study. Median follow-up was 14 months (range, 4-40 months). Although patients with MLLs had a significantly better cardiopulmonary function (P=0.0001), more conservative dose-fractionation schedules were prescribed (P=0.0001), but this did not result in a significant difference in LC (P=0.98), PFS (P=0.06) and OS (P=0.14). Multivariate analysis revealed that the dose per fraction (≥ or <12 Gy) was an independent predictor for LC (P=0.02) and PFS (P=0.01) for the whole population, and for PFS (P=0.02) in the PLLs group. Late toxicities ≥ G2 occurred in six patients with PLLs, compared with none in the metastatic group.

Conclusions: SABR for MLLs was as successful as for PLLs with respect to LC and OS with lower long-term toxicity in patients with MLLs. Dose per fraction ≥12 Gy turned out to be an independent, favorable prognostic factor.

Keywords: Lung cancer; lung metastases; oligometastatic state; stereotactic ablative radiotherapy (SABR).