Background: Epidermal growth factor receptor (EGFR) mutations are frequently found in non-small cell lung cancer (NSCLC) patients. Various EGFR mutations respond differently to EGFR tyrosine kinase inhibitors (TKIs), and several TKIs have been approved for use on common mutations but none have been approved for EGFR exon 20 insertions, indicating a need for targeted therapy for this subpopulation. A systematic literature review (SLR) and meta-analysis were conducted to synthesize epidemiological and outcome data for the uncommon EGFR exon 20 insertion mutation. Methods: An SLR was performed on August 7, 2018 following the Preferred Reporting Item for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, using the Population, Intervention Comparators, Outcomes and Study Design (PICOS) criteria. Studies were identified based on a systematic search using key biomedical literature databases: EMBASE, MEDLINE, and Cochrane. Relevant congress abstracts published between 2015–2018 were also identified. Two independent reviewers screened all citations and full-text articles using PICOS-based criteria; any discrepancies were resolved by a third independent reviewer. Data were extracted into a predefined template for meta-analysis and summarized using the PRISMA flow diagram. Results: A total of 61 studies reporting the number of EGFR mutation−positive patients and/or NSCLC patients were identified. A meta-analysis found that 3.7% of EGFR mutation−positive patients and 0.8% of NSCLC patients harbored the EGFR exon 20 insertion, with geographic variations in epidemiology. There were 12, 10, and 12 studies, respectively, that reported overall survival, progression-free survival, and overall response rates in 2 cohorts, patients with EGFR exon 20 insertions and patients without EGFR exon 20 mutations. A Most patient populations in these studies included a mixture of treatment at various lines. A meta-analysis of outcomes across these studies showed that patients with EGFR exon 20 insertions experienced worse outcomes compared with those without the mutation (Table 1). Meta-analyses were weighted based on each study’s relevant population. No economic or quality of life studies were identified. Conclusions: Exon 20 insertion mutations represent an important subgroup of EGFR mutations in patients with NSCLC, and current therapies have limited efficacy. These relatively poor outcomes indicate a need for novel treatment strategies.
