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

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.

• Authors: Kitty Huang, Max Dahele, Suresh Senan, Matthias Guckenberger, George B Rodrigues, Aaron Ward, R Gabriel Boldt, David A Palma
• Journal: Radiotherapy and oncology : journal of the European Society for Therapeutic Radiology and Oncology (Radiother Oncol) Vol. 102 Issue 3 Pg. 335-42 (Mar 2012) ISSN: 1879-0887 [Electronic] Ireland
• PMID: 22305958 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't, Review, Systematic Review)
• Copyright: Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

Topics

• Diagnosis, Differential
• Humans
• Lung Neoplasms (diagnostic imaging, surgery)
• Neoplasm Recurrence, Local (diagnosis)
• Positron-Emission Tomography
• Pulmonary Fibrosis (diagnosis)
• Radiosurgery
• Tomography, X-Ray Computed