RESUMO

BACKGROUND: Previous studies have identified that patients with EGFR mutations tend to have better responses to targeted therapy, as well as chemotherapy; however, the effect of genetic alterations in terms of radiotherapy (RT)-related outcomes has not been fully assessed. We studied the impact of common non-small cell lung cancer (NSCLC) genetic alterations (EGFR, ALK and KRAS) in relation to objective response rate (ORR) to RT in patients with brain metastases. METHODS: From 2009-2015, 153 patients with an available genotyping status were treated with whole-brain irradiation (WBI) before receiving systemic therapy. Primary outcome was ORR; secondary outcomes included intracranial progression-free survival (IPFS) and overall survival (OS). RESULTS: Overall, ORR was 47.1%. ORR to RT varied significantly according to molecular status: EGFR (64.5%) ALK (54.5%) KRAS (20%) and WT (35.4%) (P = 0.001). EGFR mutation was the only independently associated factor for response to WBI (RR 3.52 [95% CI 1.6-7.7]; P = 0.002). Median IPFS was 10.8 months [95% CI 8.2-13.5] overall; however, IPFS also varied significantly according to molecular status: EGFR (18.2 months), ALK (18.4 months), KRAS (6.0 months) and WT (8.7 months) (P < 0.0001). OS for EGFR, ALK, KRAS and WT patients was 36.6, 32.2, 15.5 and 22.4 months, respectively (P = 0.014). Intracranial-ORR (HR 0.4 [95% CI 0.2-0.6], P < 0.001) and mutation status (HR 0.7 [95% CI 0.6-0.9], P < 0.042) were independently associated with a higher OS. CONCLUSIONS: RT response varies as per tumor molecular status. The presence of EGFR mutations favors the organ-specific response to RT, and is associated with longer OS in patients with NSCLC and BM. KEY POINTS: This study addressed for the first time the difference in radiotherapy-related outcomes in patients with different genotypes of non-small cell lung cancer (NSCLC) before they received systemic therapy. Results show that response to radiotherapy varies as per tumor molecular status, particularly EGFR-mutated tumors, have a favorable response to radiotherapy, contrary to KRAS-mutated tumors.

Assuntos

Quinase do Linfoma Anaplásico/genética , Neoplasias Encefálicas/mortalidade , Carcinoma Pulmonar de Células não Pequenas/mortalidade , Regulação Neoplásica da Expressão Gênica/efeitos da radiação , Mutação , Proteínas Proto-Oncogênicas p21(ras)/genética , Adenocarcinoma de Pulmão/genética , Adenocarcinoma de Pulmão/mortalidade , Adenocarcinoma de Pulmão/patologia , Adenocarcinoma de Pulmão/radioterapia , Idoso , Idoso de 80 Anos ou mais , Biomarcadores Tumorais/genética , Neoplasias Encefálicas/genética , Neoplasias Encefálicas/radioterapia , Neoplasias Encefálicas/secundário , Carcinoma Pulmonar de Células não Pequenas/genética , Carcinoma Pulmonar de Células não Pequenas/patologia , Carcinoma Pulmonar de Células não Pequenas/radioterapia , Receptores ErbB/genética , Feminino , Seguimentos , Rearranjo Gênico , Humanos , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/mortalidade , Neoplasias Pulmonares/patologia , Neoplasias Pulmonares/radioterapia , Masculino , Pessoa de Meia-Idade , Prognóstico , Estudos Prospectivos , Radioterapia/mortalidade , Taxa de Sobrevida