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M. Guckenberger



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    MINI 18 - Radiation Topics in Localized NSCLC (ID 139)

    • Event: WCLC 2015
    • Type: Mini Oral
    • Track: Treatment of Localized Disease - NSCLC
    • Presentations: 2
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      MINI18.02 - Stereotactic Body Radiotherapy Is Safe and Effective in Octo- and Nonagenarians for the Treatment of Early Stage Lung Cancer (ID 3072)

      16:50 - 16:55  |  Author(s): M. Guckenberger

      • Abstract
      • Slides

      Background:
      To determine the safety and efficacy of lung SBRT in older patients and to compare their outcomes to those of younger patients.

      Methods:
      Patients with primary lung cancer treated with SBRT were identified from a multi-institutional (5) database of 1192 cases. Details of patient factors, treatment specifics, toxicity and clinical outcomes were extracted from the database. All events were calculated from the end of radiotherapy. Estimates of local (LR), regional (RR), and distant metastases (DM) were calculated using the competing risk method. Cause specific (CSS) and overall survival (OS) were calculated using the Kaplain-Meier method. Outcomes were compared for those <70, 70-79, >=80. Toxicity was graded per CTCAE V3.0. The 90 day mortality was reported for those <70, 70-79, >=80. Univariable analysis was performed to determine associations with CSS in patients aged >70.

      Results:
      The median follow-up was 1.7years (1-10y) and median age 75 (41-94). There were 364 patients age <70 (28%), 546 age 70-79 (42%) and 387 age ³80 (48%). 621(48%) were female, 1125(87%) were peripheral and 852(66%) were biopsied. There was no difference in baseline SUV (p=0.6), histology (p=0.4), radiation dose (p=0.1), gender (p=0.3) or biopsy rate (p=0.2) among the three age groups. Patients aged >=80 had significantly more T2 tumors 21% vs 23% vs 32 % (p<0.01). There was no difference in 5 year LR (10% vs 11.5% vs 10%, p=0.7), RR (22% vs 10% vs 9%, p=0.1), DM (17% vs 16% vs 21%, p=0.07) or CSS (80% vs 80% vs 75%, p=0.6). Those age ³80 had significantly lower 5 year OS (75% vs 44% vs 23%, p<0.01). The grade 3+ pneumonitis rate was 1.3% vs 1.6% vs 1.5% (p=0.9) in patients ages <70,70-79, >=80 respectively. The 90 day mortality rates for patients aged <70,70-79, >=80 were 1.4%, 2.7%, and 2.6% respectively. In patients aged >70 CSS was associated with tumor size (p<0.01; HR1.4) and baseline SUV max (p=0.03; HR1.04).

      Conclusion:
      SBRT is a safe treatment modality in elderly patients (aged >80). Despite larger tumor volumes, the tumor control outcome were identical to the younger patients treated with SBRT. All patients, regardless of age, should be considered for treatment of early stage lung cancer (T1-T2) with SBRT.

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      MINI18.06 - Validation of High Risk Features on CT for Detection of Local Recurrence After SBRT for Stage I NSCLC (ID 2138)

      17:15 - 17:20  |  Author(s): M. Guckenberger

      • Abstract
      • Presentation
      • Slides

      Background:
      Fibrotic changes after SBRT for stage I NSCLC are difficult to distinguish from local recurrences (LR), hampering proper selection for salvage therapy. Huang et al. (1) defined CT high risk features (HRF) for detection of LR. This study attempts to validate these HRFs in an independent patient cohort.

      Methods:
      From a multicenter combined database of patients treated with SBRT for stage I NSCLC between 2006 and 2012, 53 LR were detected of which 14 were biopsy proven. The biopsy proven LR (N=14) were matched 1:2 to patients without LR (n=28) based on: 1) dose 2) PTV 3) follow up time 4) central/peripheral location 5) lung lobe. Of the resulting 42 patients 18 were male and 24 female with a median age of 73 years (range 56-89years). Median tumor size, PTV and dose were 2.3 cm (range 1.0-4.9cm), 49cc (range 9-166cc), 48 Gy (range 48-60Gy) in 4 fractions (range 3-8) respectively. Most tumors were peripheral (76%) and located in the upper lobes (55%). Median follow up (FU) was 36 months (range 14-78months) and median time to LR was 18 months (range 12-45months). For all patients, planning CT scans and at least two follow up scans were available. Two blinded observers scored eight HRFs for each scan. Sensitivity and specificity in predicting LR were assessed and compared using Fisher’s exact test. Analysis for best fit was done using AUC.

      Results:
      Results of sensitivity and specificity are shown in Table 1. The best performing HRF was cranio-caudal growth: sensitivity 86%, specificity 82%. The odds of LR increased on average by 2.6 (95%CI1.5-4.3) for each additional HRF detected, while the AUC was 0.86. The presence of ≥ 3 HRFs resulted in the best cut-off with sensitivity 79% and specificity 86%. Loss of linear margin and bulging margin were scored identical and therefore only the latter was included in the model. The two best combinations of HRFs were: 1) bulging margin & cranio-caudal growth, with a sensitivity of 93% and specificity of 82% or 2) bulging margin & enlarging opacity after 12 months, with a sensitivity of 86% and specificity of 89%. Table 1

      CT high risk factor for local recurrence Sensitivity (%) Specificity (%) p-value
      Any HRF 93 64 .001
      enlarging opacity (≥5mm and ≥20%) 86 68 .003
      sequential enlarging opacity 57 89 .002
      enlarging opacity after 12 months 71 89 <.001
      bulging margin 64 100 <.001
      loss of linear margin 64 100 <.001
      loss of air bronchograms 7 100 0.33
      cranio-caudal growth (≥5mm and ≥20%) 86 82 <.001
      new pleural effusion 14 93 0.59


      Conclusion:
      In this matched group of biopsy proven LR and controls, cranio-caudal growth was the best individual predictor of LR after SBRT. Combining HRF bulging margin with either cranio-caudal growth or enlarging opacity after 12 months resulted in higher sensitivities and specificities than number of HRFs. 1)Huang et al. Radiotherapy&Oncology 2013

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    ORAL 19 - Radiation for Localized Lung Cancer (ID 126)

    • Event: WCLC 2015
    • Type: Oral Session
    • Track: Treatment of Localized Disease - NSCLC
    • Presentations: 2
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      ORAL19.02 - Higher Risk of Failure and Death after Stereotactic Lung Radiotherapy for T2 Lung Cancer (ID 2945)

      10:56 - 11:07  |  Author(s): M. Guckenberger

      • Abstract
      • Presentation
      • Slides

      Background:
      Limited data are available on the use of SBRT for tumors larger than 3cm. We analyzed results from a collaborative database to compare clinical outcomes for patients with tumors > 3cm to those with smaller tumors (<3cm).

      Methods:
      1192 patients with 1288 T1-T3N0M0 tumors underwent cone-beam CT image-guided lung SBRT between 10/2004-12/2014. The median prescription dose was 50 Gy in 3 fractions (range 24-64 Gy in 1-10) to the PTV. Patient, tumor and treatment factors and clinical outcomes were extracted from the database. Local recurrence (LR), regional recurrence (RR), distant metastasis (DM), overall (OS) and cause-specific survival (CSS) were calculated from SBRT completion using the Kaplan-Meier method. Univariate analyses were performed using the Cox proportional hazards model. Student’s unpaired t-test and Pearson chi-square/Fisher’s Exact test were used to compare continuous and categorical variables between groups, respectively.

      Results:
      Mean follow-up time was 2.1y (0.02-10.12y) and similar for both groups. 295 tumors were > 3cm (T2) and 993 < 3cm (T1) (mean size 3.98 v 1.91cm (0.5-9.6cm), p<0.001). There were no statistically significant differences between groups for gender, pulmonary function (median FEV1 1.7 L (56-60% predicted); DLCO 10 ml/min/mmHg (50-51% predicted), medical inoperability (89%), PET (94%) or any invasive mediastinal staging (6%). T1 patients were slightly younger (73.5y T1 v 76.0y T2, p<0.01) and had mildly better ECOG (80% 0-1 T1 v 71% 0-1 T2, p=0.001). T2 tumors were more often biopsied (74% T2 v 63% T1, p<0.001), less often non-squamous (74% v 83%, p=0.002), had higher SUVmax (10.3 T2 v 6.4 T1, p<0.001), more often central (0236) (19% T2 v 11% T1, p=0.001) and treated to a median prescription dose of 53.8Gy T2 v 52.2Gy T1, p<0.001. 3% received chemotherapy (T1 2.6% v T2 4.4%, p=0.11). Although LR was similar between groups, large tumors had a higher risk of RR, DM and death (Table 1). On univariate analysis, LR was predicted by multiple BED parameters (p<0.001), baseline SUVmax (p=0.003) and squamous histology (p=0.012); RR was higher for lower lobe tumors (p=0.008); DM (p=0.006) was higher while OS and CSS lower for central tumors (p=0.03, 0.01).

      Clinical Outcome Tumor < 3 cm Tumor > 3 cm p-value
      Local recurrence 3y 7% 11% 0.13
      5y 11% 13%
      Regional Recurrence 3y 9% 13% 0.006
      5y 11% 24%
      Distant Metastasis 3y 11% 16% <0.001
      5y 16% 18%
      Cause-Specific Survival 3y 88% 73% <0.001
      5y 81% 66%
      Overall Survival 3y 61% 45% <0.001
      5y 42% 28%


      Conclusion:
      Large tumors had a higher risk of RR, DM and death after SBRT. These data have implications for consideration and study of pre-SBRT invasive nodal staging and/or systemic therapy in this population. OS and CSS were lower for central tumors warranting further analysis.

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      ORAL19.06 - Tumor Location Is Associated with Recurrence Pattern and Survival after SBRT in Early Stage NSCLC Patients (ID 2623)

      11:39 - 11:50  |  Author(s): M. Guckenberger

      • Abstract
      • Slides

      Background:
      For NSCLC patients treated with SBRT, we investigated if tumor location is associated with recurrence pattern and overall survival.

      Methods:
      From 2006-2013 1129 patients with early stage NSCLC were treated with cone beam CT guided SBRT (median 54 Gy in 3 fractions, range 23-64 Gy in 1-10 fractions) in 5 different institutes. 719 patients were analyzed after exclusion of patients with (meta)synchronous tumors (n=185), incomplete scanning data or incomplete follow-up (n=225). An average anatomy was constructed based on 109 patients of the 5 institutes using deformable image registration[1]. Subsequently, all patients were registered to this average anatomy and the corresponding dose distribution was deformed accordingly. Tumor location was defined as a 3D Gaussian distribution (standard deviation 2 cm) at the center of the high dose region. These Gaussian distributions were added to a total and per voxel a mean and standard deviation was determined. Totals were obtained for 5 different groups: local recurrence, regional recurrence, distant metastasis, all recurrent disease combined, deceased as well as their complements. By comparing 2 complimentary groups using Welch’s t-test, locations that were significantly associated (p<0.01) with recurrent disease or with overall survival were identified. Recurrent disease rates and overall survival were calculated using the Kaplan-Meier method.

      Results:
      With a median follow-up of 19 months, local recurrence occurred in 5% of patients, regional recurrence in 5% and distant metastasis in 9%. 74% of patients were alive and 18% was lost to follow-up. Tumors located medially in the left upper lobe were significantly associated with controlled disease (local, regional, distant and all combined). Figure 1A displays as heatmap: disease control (green), recurrent disease (purple), and the region where the two groups differ significantly (yellow). Tumors located peripherally in the left lower lobe were significantly associated with regional recurrences. Tumors located medially/centrally in the right upper lobe were significantly associated with distant metastases and all recurrent disease combined (local, regional and distant together). Tumors located medially/centrally in the right upper lobe were significantly associated with a decreased overall survival (Figure 1B). Figure 1



      Conclusion:
      In this group of 719 NSCLC patients treated with SBRT, an average anatomy was utilized to analyze associations of tumor location with treatment outcome. Several regions were identified that were significantly associated with disease recurrence and overall survival. Further investigations in the underlying mechanisms of these associations are warrented. 1.ADMIRE Research 2015, Elekta AB, Stockholm, Sweden

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