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

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.

Stage I-II non-small-cell lung cancer treated using either stereotactic ablative radiotherapy (SABR) or lobectomy by video-assisted thoracoscopic surgery (VATS): outcomes of a propensity score-matched analysis.

BACKGROUND: Video-assisted thoracoscopic surgery (VATS) lobectomy and stereotactic ablative radiotherapy (SABR) are both used for early-stage non-small-cell lung cancer. We carried out a propensity score-matched analysis to compare locoregional control (LRC). PATIENTS AND METHODS: VATS lobectomy data from six hospitals were retrospectively accessed; SABR data were obtained from a single institution database. Patients were matched using propensity scores based on cTNM stage, age, gender, Charlson comorbidity score, lung function and performance score. Eighty-six VATS and 527 SABR patients were matched blinded to outcome (1:1 ratio, caliper distance 0.025). Locoregional failure was defined as recurrence in/adjacent to the planning target volume/surgical margins, ipsilateral hilum or mediastinum. Recurrences were either biopsy-confirmed or had to be PET-positive and reviewed by a tumor board. RESULTS: The matched cohort consisted of 64 SABR and 64 VATS patients with the median follow-up of 30 and 16 months, respectively. Post-SABR LRC rates were superior at 1 and 3 years (96.8% and 93.3% versus 86.9% and 82.6%, respectively, P = 0.04). Distant recurrences and overall survival (OS) were not significantly different. CONCLUSION: This retrospective analysis found a superior LRC after SABR compared with VATS lobectomy, but OS did not differ. Our findings support the need to compare both treatments in a randomized, controlled trial.

Early-stage lung cancer in elderly patients: a population-based study of changes in treatment patterns and survival in the Netherlands.

BACKGROUND: Elderly patients with stage I non-small-cell lung cancer are less likely to undergo curative treatment. However, the introduction of new treatment options such as stereotactic ablative radiotherapy (SABR) may improve treatment rates. We evaluated time trends in treatment patterns and survival in the entire Netherlands population for patients diagnosed between 2001 and 2009. PATIENTS AND METHODS: Details of 4605 elderly Dutch patients were obtained from the Netherlands Cancer Registry, containing data on all cancer patients in a population of 16 million. Three consecutive time periods were studied: 2001-2003 (A, before SABR became available), 2004-2006 (B, increasing availability), and 2007-2009 (C, full availability). RESULTS: Between period A and C, there was a 7% absolute reduction in patients going untreated, corresponding to an 8-month improvement in median survival (P < 0.001). Radiotherapy utilization increased from 31% to 38%, whereas surgical utilization remained constant (37%). Significant improvements in survival were observed in the radiotherapy subgroup (P < 0.001) and surgery subgroup (P < 0.001), not in patients going untreated. There was no evidence of stage migration. CONCLUSIONS: Population-based increases in survival of elderly stage I lung cancer patients were seen between 2001 and 2009. The introduction of SABR correlated with a decline in the number of untreated patients.

Defining target volumes for stereotactic ablative radiotherapy of early-stage lung tumours: a comparison of three-dimensional 18F-fluorodeoxyglucose positron emission tomography and four-dimensional computed tomography.

AIMS: High local control rates are achieved in stage I lung cancer using stereotactic ablative radiotherapy. Target delineation is commonly based on four-dimensional computed tomography (CT) scans. Target volumes defined by positron emission tomography/computed tomography (PET/CT) are compared with those defined by four-dimensional CT and conventional ('three-dimensional') (18)F-fluorodeoxyglucose ((18)F-FDG) PET/CT. MATERIALS AND METHODS: For 16 stage I non-small cell lung cancer tumours, six approaches for deriving PET target volumes were evaluated: manual contouring, standardised uptake value (SUV) absolute threshold of 2.5, 35% of maximum SUV (35%SUV(MAX)), 41% of SUV(MAX) (41%SUV(MAX)) and two different source to background ratio techniques (SBR-1 and SBR-2). PET-derived target volumes were compared with the internal target volume (ITV) from the modified maximum intensity projection (MIP(MOD) ITV). Volumetric and positional correlation was assessed using the Dice similarity coefficient (DSC). RESULTS: PET-based target volumes did not correspond to four-dimensional CT-based target volumes. The mean DSC relative to MIP(MOD) ITV were: PET manual = 0.64, SUV2.5 = 0.64, 35%SUV(MAX) = 0.63, 41%SUV(MAX) = 0.57. SBR-1 = 0.52, SBR-2 = 0.49. PET-based target volumes were smaller than corresponding MIP ITVs. CONCLUSIONS: Conventional three-dimensional (18)F-FDG PET-derived target volumes for lung stereotactic ablative radiotherapy did not correspond well with those derived from four-dimensional CT, including those in routine clinical use (MIP(MOD) ITV). Caution is required in using three-dimensional PET for motion encompassing target volume delineation.