Incidence of High-Risk Radiologic Features in Patients Without Local Recurrence After Stereotactic Ablative Radiation Therapy for Early-Stage Non-Small Cell Lung Cancer

M. I. Ronden, J. R. van Sörnsen de Koste*, C. Johnson, B. J. Slotman, F. O.B. Spoelstra, C. J.A. Haasbeek, G. Blom, E. M. Bongers, A. Warner, A. Ward, D. Palma, S. Senan

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review


PURPOSE: To investigate, in the setting of stereotactic ablative radiation therapy (SABR) for early-stage non-small cell lung cancer, the incidence and patterns of change in high-risk radiologic features (HRFs) in patients known to have no local recurrence.

METHODS AND MATERIALS: Computed tomography (CT) scans of patients treated using volumetric modulated arc therapy SABR between 2008 and 2013 were eligible if follow-up scans were available for 2 years and no local recurrences were diagnosed. All scans were reviewed at a workstation using an add-on tool for ClearCanvas (Synaptive Medical). Five clinicians who were blinded to clinical outcomes scored the presence of HRFs: enlarging opacity (EO), sequential enlarging opacity, enlarging opacity after 12 months (EO12), bulging margin, loss of linear margins, cranio-caudal growth, and loss of air bronchogram. After each review, clinicians recommended follow-up procedures based on published recommendations.

RESULTS: A total of 88 patients (747 CT scans) were evaluated. The HRFs most frequently recorded by ≥3 observers on at least 1 follow-up scan were EO (64.8%), EO12 (50.0%), and sequential enlarging opacity (13.6%). Fifty-six patients developed EO within the first year after SABR, and of these, 46 also developed subsequent EO (EO12). In 76 patients who developed EO after 1 year of follow-up, 30 had not manifested EO previously. Three or more HRFs have been associated with recurrences, and this was observed on CT scan in 22.7% of patients. In their routine care, 6 patients had undergone a positron emission tomography scan because of a suspected local recurrence, and 4 underwent an attempt at biopsy.

CONCLUSIONS: More than 50% of patients without a local recurrence after SABR develop HRFs. Because ≥3 HRFs were present in nearly 25% of patients, further refinement of follow-up recommendations are necessary.

Original languageEnglish
Pages (from-to)115-121
Number of pages7
JournalInternational Journal of Radiation Oncology Biology Physics
Issue number1
Publication statusPublished - 1 Jan 2018

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