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P1.06 - Poster Session 1 - Prognostic and Predictive Biomarkers (ID 161)
- Event: WCLC 2013
- Type: Poster Session
- Track: Biology
- Presentations: 1
- Coordinates: 10/28/2013, 09:30 - 16:30, Exhibit Hall, Ground Level
P1.06-059 - Comparison of the characteristics and clinical course of patients with metastatic KRAS mutant lung cancers (ID 3484)
09:30 - 16:30 | Author(s): M.G. Kris
Patients (pts) with KRAS mutant lung cancers have a shorter survival compared to pts withKRAS/EGFR wild type tumors(Johnson et al, Cancer 2013). Whether outcomes for patients with KRASmutant metastatic lung cancers differ by smoking status or specific amino acid substitution is unknown. In order to understand the impact of KRAS mutation subtype in the metastatic setting, we analyzed a large cohort of patients with KRAS mutant metastatic lung cancer.
We identified all pts with KRAS mutant metastatic or recurrent lung cancers from Feb 2005 to Aug 2011. KRAS mutation type, clinical characteristics, and outcomes from diagnosis were obtained from the medical record. A multivariate cox proportion hazard model was used to identify factors associated with overall survival.
KRAS mutations were identified in 677 pts (53 at codon 13, 624 at codon 12). Median age: 66 (range 31-89), women: 62%, never smokers: 7%. Pts with transition mutations (n=157) were more likely to be never-smokers (p<0.0001). There was no difference in outcome for pts with KRAS transition versus transversion mutations (p=1) or when comparing current/former smokers to never smokers (p=0.33). There was no difference in overall survival (OS) when comparing specific amino acid substitutions (G12C=366, G12V=141, G12D=114, G12A=68, G13C=27, G13D=23, G12S=19, G12F=11)(p=0.20). Pts with KRAS codon 13 mutant tumors had inferior OS compared to pts with codon 12 mutant tumors, median 13 months (mo) (95% CI 13-17 mo) and 16 mo (95% CI 9-16 mo), respectively (p=0.009). There was no difference in frequency of receiving platinum-based chemotherapy or chemotherapy of any kind between pts with codon 12 and 13 mutant tumors. In a multivariate Cox model which included age, gender and smoking status, KRAS codon 13 mutation was associated with worse overall survival than KRAS codon 12 mutation (HR 1.52 95% CI 1.11-2.08 p=0.008).
Among pts with KRAS mutant metastatic lung cancers, smoking history, and specific amino acid substitution do not affect outcome. Among patients with KRAS mutant metastatic lung cancers, those with codon 13 mutations have shorter survival compared to pts with KRAS codon 12 mutations.