Radiographic changes after lung stereotactic ablative radiotherapy (SABR) – Can we distinguish recurrence from fibrosis? A systematic review of the literature

Huang, Kitty; Dahele, Max; Senan, Suresh; Guckenberger, Matthias; Rodrigues, George B.; Ward, Aaron; Boldt, R. Gabriel; Palma, David A.

doi:10.1016/j.radonc.2011.12.018

« Previous Next »Radiotherapy & Oncology
Volume 102, Issue 3 , Pages 335-342, March 2012

Radiographic changes after lung stereotactic ablative radiotherapy (SABR) – Can we distinguish recurrence from fibrosis? A systematic review of the literature

Kitty Huang
- Department of Radiation Oncology, London Health Sciences Centre, London, Canada
- Department of Oncology, University of Western Ontario, London, Canada
Max Dahele
- Department of Radiation Oncology, VU University Medical Center, Amsterdam, The Netherlands
Suresh Senan
- Department of Radiation Oncology, VU University Medical Center, Amsterdam, The Netherlands
Matthias Guckenberger
- Department of Radiation Oncology, University Hospital Wuerzburg, Wuerzburg, Germany
George B. Rodrigues
- Department of Radiation Oncology, London Health Sciences Centre, London, Canada
- Department of Oncology, University of Western Ontario, London, Canada
- Department of Epidemiology and Biostatistics, University of Western Ontario, London, Canada
Aaron Ward
- Department of Oncology, University of Western Ontario, London, Canada
R. Gabriel Boldt
- Department of Radiation Oncology, London Health Sciences Centre, London, Canada
David A. Palma
- Department of Radiation Oncology, London Health Sciences Centre, London, Canada
- Department of Oncology, University of Western Ontario, London, Canada
- Corresponding author. Address: London Regional Cancer Program, 790 Commissioners Rd. E., London, Ontario, Canada.

Received 4 October 2011; received in revised form 15 December 2011; accepted 23 December 2011. published online 06 February 2012.

Abstract

Background

Changes in lung density on computed tomography (CT) are common after stereotactic ablative radiotherapy (SABR) and can confound the early detection of recurrence. We performed a systematic review to describe post-SABR findings on computed tomography (CT) and positron-emission tomography (PET), identify imaging characteristics that predict recurrence and propose a follow-up imaging algorithm.

Methods

A systematic review was conducted of studies providing detailed radiologic descriptions of anatomic and metabolic lung changes after SABR. Our search returned 824 studies; 26 met our inclusion criteria. Data are presented according to PRISMA guidelines.

Results

Acute changes post-SABR predominantly appear as consolidation or ground glass opacities. Late changes often demonstrate a modified conventional pattern of fibrosis, evolving beyond 2years after treatment. Several CT features, including an enlarging opacity, correlate with recurrence. Although PET SUVmax may rise immediately post-SABR, an SUVmax⩾5 carries a high predictive value of recurrence.

Conclusions

CT density changes are common post-SABR. The available evidence suggests that recurrent disease should be suspected if high-risk CT changes are seen with SUVmax⩾5 on PET. Further studies are needed to validate the predictive values of such metrics, and for advanced analysis of CT changes to allow early detection of potentially curable local recurrence.

Keywords: Stereotactic radiation, Lung cancer, Computed tomography, Positron emission tomography, Local recurrence