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R. Mehran



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    MO17 - Radiotherapy I: Stereotactic Ablative Body Radiotherapy (ID 106)

    • Event: WCLC 2013
    • Type: Mini Oral Abstract Session
    • Track: Radiation Oncology + Radiotherapy
    • Presentations: 1
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      MO17.11 - Stereotactic ablative radiotherapy (SABR) for centrally located early-stage or isolated parenchymal recurrences of non-small cell lung cancer (NSCLC): How to fly in a "no fly zone" (ID 1961)

      17:15 - 17:20  |  Author(s): R. Mehran

      • Abstract
      • Presentation
      • Slides

      Background
      SABR has become a standard treatment option for medically inoperable, peripherally located early-stage NSCLC. However, using SABR for centrally located lesions remains challenging because of the potential for severe side effects. Here we sought to validate our previous experience with SABR (50 Gy in 4 fractions) for central lesions, including the dose-volume constraints, and explore a new regimen of 70 Gy in 10 fractions for cases in which dose-volume constraints cannot be met with the previous regimen.

      Methods
      We used 4D-based, volumetric image-guided SABR to treat 101 patients with biopsy-proven and PET/CT-staged centrally located (within 2 cm of bronchial tree, trachea, major vessels, esophagus, heart, pericardium, brachial plexus or vertebral body) T1-2N0M0 tumors (n=82) or isolated lung-parenchyma recurrent lesions (n=19). The treatment period spanned February 2005 through May 2011; follow-up visits (every 3 months for 2 years and every 6 months for the next 3 years) included chest CT or PET/CT. Endpoints were toxicity (CTCAE v3.0), survival, local control, regional control, and distant metastasis.

      Results
      At a median follow-up time of 30.3 months for all patients (40.5 months for those alive), median overall survival time was 56.5 months and 5-year overall survival rate was 49.0%. Three-year actuarial local, regional, and distant control rates were 96.5%, 87.2% and 77.3%. The most common toxicities were chest-wall pain (18% grade 1 and 13% grade 2) and radiation pneumonitis (10.9% grade 2 and 1.9% grade 3). No patient experienced grade 4 toxicity and one patient with tumor invading bronchial tree who received 70 Gy in 10 fractions died from hemoptysis 13 months after SABR. The distance between tumor and chest was associated with chest wall pain (≤1 cm 45% vs >1 cm 17%, p=0.002). Univariate and multivariate analyses showed that for the 82 patients receiving 50 Gy in 4 fractions, mean total lung dose (MLD) >5 Gy or ipsilateral lung V~20~ (iV~20~) >16% were independent predictors of radiation pneumonitis; 3 of 9 patients in that group with D~max~ to brachial plexus >35 Gy experienced brachial neuropathy versus none of the 73 patients with brachial D~max~ ≤ 35 Gy (p=0.001).

      Conclusion
      SABR for centrally located lesions produces clinical outcomes similar to those for peripheral lesions when normal tissue constraints are respected. For 50 Gy in 4 fractions, we recommend MLD ≤5 Gy, lung iV~20~ ≤16%; bronchial tree D~max~ ≤ 38 Gy, V~35~ ≤1 cm[3]; major vessel D~max~≤ 56 Gy, V~40~≤1 cm[3]; esophageal D~max~ ≤35 Gy, V~30~≤1 cm[3 ]; brachial plexus D~max~ ≤35 Gy, V~30~≤0.2 cm[3] and spinal cord D~max~ <25 Gy. Giving 70 Gy in 10 fractions is another option for challenging cases but can produce severe toxicity if significant amounts of critical structures are exposed to ≥70 Gy. Proper selection of cases (based on tumor location and normal tissue constraints) and SABR regimens and volumetric image-guided delivery are all crucial to avoid overdosing critical structures. Typically, a minimum 5-10 mm distance between critical structures and gross tumor is required to meet dose-volume constraints.

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    P1.07 - Poster Session 1 - Surgery (ID 184)

    • Event: WCLC 2013
    • Type: Poster Session
    • Track: Surgery
    • Presentations: 1
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      P1.07-010 - Preoperative Flourodeoxyglucose-Positron Emission Tomography Scan with Positive N1 Disease Does Not Predict Worse Survival in Pathologic Stage II Patients (ID 1070)

      09:30 - 09:30  |  Author(s): R. Mehran

      • Abstract

      Background
      The rate of fluorodeoxyglucose uptake measured as standardized uptake value (SUV) on positron emission tomography (PET) of the primary tumor has been correlated with tumor aggressiveness and poor survival in patients with lung cancer. A retrospective review of patients with lung cancer who were treated with surgical resection at MD Anderson Cancer Center (MDACC) was performed to determine if the pre-operative SUV uptake of N1 disease has any prognostic significance in patients with pathologic stage II lung cancer.

      Methods
      We reviewed all patients who underwent surgical resection for lung cancer at MDACC from 1998 to 2011. We evaluated non-small cell lung cancer patients who had at least a lobectomy at MDACC as first mode of surgical therapy who had pathologic stage T1-2 and N1 disease and pre-operative PET-CT scan. We determined the clinicopathologic characteristics of patients who had PET-positive N1 disease and compared them to patients who had PET-negative N1 disease. We also performed Kaplan Meier analysis to determine the survival between the two groups.

      Results
      Among patients who underwent surgical resection for lung cancer at MDACC during this time period, 120 patients met the inclusion criteria for the study. There were 100 stage IIA or T1aN1, T1bN1 or T2aN1 and 20 stage IIB or T2bN1 patients in the study. There were 62 patients (50% of the patients) who had a primary tumor in the periphery of the lung and 58 patients (50% of the patients) who had a primary tumor in the central portion of the lung. Within this group of 120 patients, only 29 patients (24% of the patients) had PET-positive N1 disease. Only 16 out of 58 patients (28%) in the central group and only 13 out of 62 patients (21%) in the peripheral group had PET-positive N1 disease. There was no clinical or pathological difference between the patients who had PET-positive N1 disease and PET-negative N1 disease. The average maxSUV of the primary tumor was 13 ± 10.7 and average maxSUV of the PET-positive N1 disease was 6.3 ± 4.1. Kaplan Meier analysis showed that there was no significant difference in survival between the patients who had PET-positive N1 disease and PET-negative N1 disease.

      Conclusion
      Among patients with pathologic stage II non-small cell lung cancer, preoperative PET scan was very poor at predicting positive pathologic N1 disease. Since it is difficult to predict pN1 disease, operative patients with clinical stage I non-small cell lung cancer should have surgical resection oppose to ablative therapy. Moreover, SUV uptake of N1 disease in patients with pathologic stage II lung cancer did not predict worse survival in pathologic stage II patients. Thus, patients with cN1 disease should undergo surgical resection after appropriate mediastinal staging.