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

Pros: After stereotactic ablative radiotherapy for a peripheral early-stage non-small cell lung cancer, radiological suspicion of a local recurrence can be sufficient indication to proceed to salvage therapy

“…Using FDG-PET scans to help distinguish between fibrosis and LR is confounded by the risk of false positives due to the increased metabolic activity related to RILI. Several studies have reported, however, that using a threshold SUV max of ≥5, or greater than SUV max prior to treatment, may be a more reliable predictor of LR (6).…”

“…Following SABR, radiation-induced lung injury (RILI) is common, which manifests as local changes to the lung parenchyma on CT imaging that are usually asymptomatic. Both acute (within 6 months) and late (after 6 months) changes have been previously described and can obscure the detection of residual and recurrent disease (6). Acute changes have been categorized as one of 4 types: diffuse consolidation, patchy consolidation, diffuse ground-glass Controversies on Lung Cancer: Pros and Cons Pros: After stereotactic ablative radiotherapy for a peripheral early-stage non-small cell lung cancer, radiological suspicion of a local recurrence can be sufficient indication to proceed to salvage therapy opacities, or patchy ground-glass opacities.…”

Stereotactic radiotherapy for early lung cancer: Evidence-based approach and future directions

“…48 PET-CT may be helpful to distinguish recurrence from fibrosis, but low-or moderategrade FDG uptake can be found after SBRT in the absence of malignancy. 49 Recently, high-risk features (HRFs) on CT have shown promise as predictors of recurrence. Such HRFs include an enlarging opacity (particularly >1 year post-treatment), sequential enlargement, growth in the cranio-caudal direction, and loss of air bronchograms.…”

Non-small cell lung cancer after surgery and chemoradiotherapy: follow-up and response assessment

“…Furthermore, positive CT changes associated with increased FDG uptake (SUV max ≥5) very likely indicate residual or recurrent lung cancer, and additional diagnostic or interventional procedures (bronchoscopy, percutaneous needle-aspiration biopsy, open lung biopsy, thoracentesis, etc.) are required (43).…”