AbstractBackground and ObjectivesPrecision medicine has altered the management of colorectal cancer (CRC). However, the concordance of mutational findings between primary CRC tumors and associated pulmonary metastases (PM) is not well‐described. This study aims to determine the concordance of genomic profiles between primary CRC and PM.MethodsPatients treated for colorectal PM at a single institution from 2000 to 2017 were identified. Mutational concordance was defined as either both wild‐type or both mutant alleles in lung and colorectal lesion; genes with opposing mutational profiles were reported as discordant.ResultsThirty‐eight patients met inclusion criteria, among whom KRAS, BRAF, NRAS, MET, RET, and PIK3CA were examined for concordance. High concordance was demonstrated among all evaluated genes, ranging from 86% (KRAS) to 100% concordance (NRAS, RET, and MET). De novo KRAS mutations were detected in the PM of 4 from 35 (11%) patients, 3 of whom had previously received anti‐epidermal growth factor receptor (EGFR) therapy. Evaluation of Cohen's κ statistic demonstrated moderate to perfect correlation among evaluated genes.ConclusionsBecause high intertumoral genomic homogeneity exists, it may be reasonable to use primary CRC mutational profiles to guide prognostication and targeted therapy for PM. However, the possibility of de novo KRAS‐mutant PM should be considered, particularly among patients previously treated with anti‐EGFR therapy.
Abstract 3626: Inflammation-related genetic variants predict radiation-induced toxicity following definitive radiotherapy for non-small cell lung cancer.
Abstract Definitive radiotherapy combined with chemotherapy is associated with enhanced locoregional control and clinical outcomes in non-small cell lung cancer (NSCLC) patients who are not candidates for surgery. However, radiation-induced pneumonitis and esophagitis are common dose-limiting inflammatory conditions that occur in these patients. These events can compromise the effect of the overall treatment and reduce quality of life in these patients. It is not clear what factors contribute to differences in the development of toxicities among patients with same clinical or dosimetric parameters. In this study, we conducted a large scale pathway-based analysis to identify inflammation-related genetic variants associated with radiation-induced pneumonitis or esophagitis. In the initial discovery phase, 11,930 inflammation-related genetic variants were genotyped in 243 stage I-III NSCLC patients who were treated with definitive radiotherapy at MD Anderson Cancer Center. A fast-track validation was performed for the top candidate SNPs in an additional 212 NSCLC cases following the same criteria. A total of 14 SNPs and 12 SNPs were validated for pneumonitis and esophagitis, respectively. Meta-analysis was used to summarize the results from two phases. The most significant SNPs for esophagitis and pneumonitis mapped to chromosome 18p (OR=9.05, 95%CI=2.68-30.59, P-meta=3.90×10−4) and 14q (OR=4.75, 95%CI=2.17-10.41, P-meta =9.61×10−5), respectively. To explore the potential underlying mechanisms, we analyzed radiation sensitivity and eQTL relationships of the identified SNPs and their host genes in 277 ethnically defined human lymphoblastoid cell lines. Among the 24 host genes for the 26 identified SNPs, three genes (DDX58, GZMB, CDC2) showed significant association with radiation responses in these cell lines (P<0.05). Moreover, a significant eQTL relationship was identified between CDC2 expression and the genotype of the identified CDC2 SNP (P=0.022). Interestingly, this CDC2 SNP is predicted to create a new miRNA binding site. Luciferase reporter assays to test the influence of this SNP on miRNA regulation is currently ongoing. Our results provide evidence that inflammation-related genetic variants contribute to the development of radiation-induced pneumonitis and esophagitis. The results also suggest that gene expression changes through altered miRNA binding may be an underlying mechanism for these events. Citation Format: Xia Pu, Liewei Wang, Michelle AT Hildebrandt, Yuanqing Ye, Joe Y. Chang, Charles Lu, Heath D. Skinner, Nifang Niu, Gregory D. Jenkins, Ritsuko Komaki, John D. Minna, Jack A. Roth, Richard M. Weinshilboum, Xifeng Wu. Inflammation-related genetic variants predict radiation-induced toxicity following definitive radiotherapy for non-small cell lung cancer. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 3626. doi:10.1158/1538-7445.AM2013-3626
Genome-Wide Association Study of Genetic Predictors of Overall Survival for Non–Small Cell Lung Cancer in Never Smokers
Abstract Lung cancer in never-smokers is increasingly recognized as distinct from that in ever-smokers owing to substantial differences in etiology, clinical characteristics, and prognosis. Therefore, we aimed to identify prognostic markers specific for lung cancer in never-smokers in a two-stage study. First, 11,930 single-nucleotide polymorphisms (SNPs) in 904 inflammation-related genes were genotyped, and their associations with overall survival in 411 never-smokers with lung cancer at The University of Texas MD Anderson Cancer Center were analyzed. Next, fast-track validation of the top 37 SNPs in 311 never-smokers with lung cancer at Mayo Clinic was performed. Three SNPs (interleukin 17 receptor A:rs879576, bone morphogenetic protein 8A:rs698141, and spleen tyrosine kinase:rs290229) were validated (p<0.05), and two more SNPs (CD74:rs1056400 and CD38:rs10805347) were borderline significant (p=0.08) in the Mayo Clinic population. In combined analysis of the MD Anderson and Mayo Clinic patients, IL17RA:rs879576 resulted in a 40% reduction in the risk of death (p=4.1 × 10−5 [p=0.61, heterogeneity test]). We successfully validated a survival tree created in MD Anderson population based on gene-gene interactions in the Mayo Clinic population. This survival tree stratified patients into subsets with significantly different risks of death: patients at MD Anderson with the rs1056400_GG/rs698141_GA+AA genotype had a 2.32-fold higher risk of death (p=1.72 × 10−5) and 9-month shorter median survival time (MST) (p=4.5 × 10−4, log-rank test) than did those with the rs1056400_GG/rs698141_GG or rs1056400_GA+AA genotype in the discovery phase. Also, the patients at Mayo Clinic with the former genotype had an approximately twofold higher risk of death (p=0.02) and a strikingly shorter (by 26 months) MST (p=0.029, log-rank test) than did those with the latter genotype in the validation phase. We evaluated these five SNPs in 996 ever-smokers and found no significant associations. To our knowledge, this is the first study to systematically evaluate the associations of genetic variations in major inflammation-related genes with outcome of lung cancer in never-smokers. It provides strong evidence that inflammation-related genetic variations can affect clinical outcomes in these patients, which may lead to significant biological insight into these outcomes. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 2929. doi:1538-7445.AM2012-2929
Long-Term Results of RTOG Trial 8911 (USA Intergroup 113): A Random Assignment Trial Comparison of Chemotherapy Followed by Surgery Compared With Surgery Alone for Esophageal Cancer
Purpose We update Radiation Therapy Oncology Group trial 8911 (USA Intergroup 113), a comparison of chemotherapy plus surgery versus surgery alone for patients with localized esophageal cancer. The relationship between resection type and between tumor response and outcome were also analyzed. Patients and Methods The chemotherapy group received preoperative cisplatin plus fluorouracil. Outcome based on the type of resection (R0, R1, R2, or no resection) was evaluated. The main end point was overall survival. Disease-free survival, relapse pattern, the influence of postoperative treatment, and the relationship between response to preoperative chemotherapy and outcome were also evaluated. Results Two hundred sixteen patients received preoperative chemotherapy, 227 underwent immediate surgery. Fifty-nine percent of surgery only and 63% of chemotherapy plus surgery patients underwent R0 resections (P = .5137). Patients undergoing less than an R0 resection had an ominous prognosis; 32% of patients with R0 resections were alive and free of disease at 5 years, only 5% of patients undergoing an R1 resection survived for longer than 5 years. The median survival rates for patients with R1, R2, or no resections were not significantly different. While, as initially reported, there was no difference in overall survival for patients receiving perioperative chemotherapy compared with the surgery only group, patients with objective tumor regression after preoperative chemotherapy had improved survival. Conclusion For patients with localized esophageal cancer, whether or not preoperative chemotherapy is administered, only an R0 resection results in substantial long-term survival. Even microscopically positive margins are an ominous prognostic factor. After a R1 resection, postoperative chemoradiotherapy therapy offers the possibility of long-term disease-free survival to a small percentage of patients.