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K. Barrett



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    O01 - Prognostic and Predictive Biomarkers I (ID 94)

    • Event: WCLC 2013
    • Type: Oral Abstract Session
    • Track: Medical Oncology
    • Presentations: 1
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      O01.01 - Genetic polymorphisms of inflammatory and DNA repair pathways, radiation-related esophagitis and pneumonitis in definitive chemoradiation treated non-small cell lung cancer patients. (ID 2997)

      10:30 - 12:00  |  Author(s): K. Barrett

      • Abstract
      • Presentation
      • Slides

      Background
      The benefits of concurrent chemoradiotherapy in locally advanced non-small cell lung cancer (NSCLC) are tempered by treatment toxicity. Germline genetic variants have been associated with intrinsic radiosensitivity and radiotoxicity in various cancer settings. We investigated whether variants in genes involved in inflammation response and DNA repair pathways independently influence radiation-induced phenotypes of esophagitis and pneumonitis. From 19 candidate genes, 52 polymorphisms, directed by literature and by tagging procedures, were systematically selected for assessment. The candidate genes were involved in DNA repair (double-strand breaks, homology directed, nucleotide excision) and pro/anti-inflammatory signaling. The this investigation sought to evaluate the association of genetic sequence markers for two clinically significant radiation-induced toxicities - esophagitis and pneumonitis – seen in NSCLC patients treated with a curative intent.

      Methods
      From 312 patients treated at PMCC between 2005-12, a training cohort was defined consisting of 92 definitive concurrent chemoradiation/radiation-treated NSCLC patients with genotype information on the 52 polymorphisms. A second, validation cohort consisted of 209 patients. Multivariate logistic regression was performed for each polymorphism of interest, adjusting for known clinical and dosimetric prognostic factors on the dichotomized outcomes of radiation esophagitis (Grades 0-2 vs 3-5) and pneumonitis (Grades 0-1 vs 2-5). The CTCAEv4.03 grading criteria were used. Additive genetic models were used for genetic association analysis. In the training set, genetic variants, genotyped by IlluminaGoldenGate, with p<=0.05 were identified for validation; HWE was set at p>0.01, a criteria met by all polymorphisms with statistical significance.

      Results
      In the combined training and validation datasets, 63% were males, with median age of 65 years. Specifically in the training dataset, 65% were male, with median age of 62, median mean lung doses of 15.9, median max esophageal dose of 67.1 and median V20 of 27.6. For esophagitis, the final models were adjusted for concurrent chemotherapy, V20 and max esophageal dose. Five genetic variants linked to TNF and IL6 were significantly associated with outcome (each using wild-type genotype as reference) (Table 1). For pneumonitis, the final models adjusted for V20 and smoking status. Eight genetic variants found within four genes (ATM, BRCA2, IL1alpha, IL1RN) were associated with significant pneumonitis (Table 1).

      ESOPHAGITIS
      Function / Pathway Gene refSNP OR 95% CI P value
      pro-inflammatory cytokine TNF rs3093662 3.54 1.9-10.6 0.02
      pro-inflammatory cytokine TNF rs3093664 3.42 1.2-10.2 0.03
      pro-inflammatory cytokine TNF rs3093665 4.95 1.2-21.1 0.03
      anti-inflammatory cytokine IL6 rs1800797 2.53 1.0-6.2 0.04
      anti-inflammatory cytokine IL6 rs1800795 2.45 1.0-5.9 0.046
      PNEUMONITIS
      Function / Pathway Gene refSNP OR 95% CI P value
      double-strand break repair ATM rs664143 2.67 1.3-5.6 0.01
      double-strand break repair ATM rs664677 2.37 1.2-4.7 0.01
      homology-directed repair BRCA2 rs1799955 2.59 1.3-5.3 0.01
      homology-directed repair BRCA2 rs1801406 2.42 1.2-4.8 0.01
      homology-directed repair BRCA2 rs1799943 2.09 1.0-4.2 0.04
      anti-inflammatory cytokine IL1alpha rs17561 2.63 1.2-5.7 0.01
      anti-inflammatory cytokine IL1alpha rs2856863 2.60 1.1-5.9 0.02
      anti-inflammatory cytokine IL1RN rs3087263 0.17 0.04-0.8 0.04

      Conclusion
      In our 92 patient training set, genetic variations in TNF and IL6 are associated with radiation esophagitis, while genetic variations in ATM, BRCA2, IL1alpha and IL1RN are associated with pneumonitis. Results from the 209 patients in the validation dataset will be presented at the meeting (A.H. and G. L are co-senior authors).

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