Exons 19 and 21 of epidermal growth factor receptor are highly conserved in squamous cell cancer of the head and neck

Cost-effectiveness analysis comparing companion diagnostic tests for EGFR, ALK, and ROS1 versus next-generation sequencing (NGS) in advanced adenocarcinoma lung cancer patients

BACKGROUND

The treatment of choice for advanced non-small cell lung cancer is selected according to the presence of specific alterations. Patients should undergo molecular testing for relevant modifications and the mutational status of EGFR and translocation of ALK and ROS1 are commonly tested to offer the best intervention. In addition, the tests costs should also be taken in consideration. Therefore, this work was performed in order to evaluate the cost-effectiveness of a unique exam using NGS (next generation sequencing) versus other routinely used tests which involve RT-PCR and FISH.

METHODS

The target population was NSCLC, adenocarcinoma, and candidates to first-line therapy. Two strategies were undertaken, strategy 1 corresponded to sequential tests with EGFR RT-PCR, then FISH for ALK and ROS1. Strategy 2 differed from 1 in that ALK and ROS1 translocation testing were performed simultaneously by FISH. Strategy 3 considered single test next-generation sequencing, a platform that includes EGFR, ALK and ROS1 genes. A decision tree analysis was used to model genetic testing options. From the test results, a microsimulation model was nested to estimate survival outcomes and costs of therapeutic options.

RESULTS

The use of NGS added 24% extra true cases as well as extra costs attributed to the molecular testing. The ICER comparing NGS with sequential tests was US$ 3479.11/correct case detected. The NGS improved a slight gain in life years and QALYs.

CONCLUSION

Our results indicated that, although precise, the molecular diagnosis by NGS of patients with advanced stage NSCLC adenocarcinoma histology was not cost-effective in terms of quality-adjusted life years from the perspective of the Brazilian supplementary health system.

Prevalence of EGFR Tyrosine Kinase Domain Mutations in Head and Neck Squamous Cell Carcinoma: Cohort Study and Systematic Review

BACKGROUND

Mutations in the epidermal growth factor receptor (EGFR) tyrosine kinase domain (TKD) are associated with response and resistance to targeted therapy. The EGFR mutation status in patients with advanced oral and oropharyngeal squamous cell carcinoma (OOSCC) was evaluated. A systematic literature review was undertaken to summarize current evidence and estimate the overall prevalence of EGFR TKD mutations in patients with head and neck squamous cell carcinoma (HNSCC).

MATERIALS AND METHODS

Genomic DNA was extracted from formalin-fixed, paraffin-embedded tumor samples of 113 patients with OOSCC. Pyrosequencing was performed to investigate mutations in EGFR exons 18 to 21. Medline databases were searched for relevant studies. Studies reporting mutations in the EGFR TKD in HNSCC were eligible for inclusion in the systematic review.

RESULTS

No mutations in the EGFR TKD were observed in 113 samples of OOSCC. A total of 53 eligible studies were included in the systematic review. In total, from the review, 117 patients harboring a total of 159 EGFR TKD mutations were reported among 4122 patients with HNSCC. The overall prevalence of EGFR TKD mutations in HNSCC was 2.8%.

CONCLUSION

Large-scale studies are warranted to provide further evidence regarding the mutation status of EGFR in patients with HNSCC.

Clinical significance of genetic alterations and expression of epidermal growth factor receptor (EGFR) in head and neck squamous cell carcinomas

The significance of epidermal growth factor receptor (EGFR) signaling is well studied in a number of different tumors, but limited data is available with regard to head and neck squamous cell carcinoma (HNSCC). Since anti-EGFR therapies are currently under investigation in these malignancies as well, comprehensive information about the alteration of EGFR in HNSCC is necessary to design the most appropriate therapeutic protocols. We examined retrospectively the gene copy number of EGFR by FISH and the protein expression by immunohistochemistry using different epitope-specific antibodies in paraffin-embedded primary tumors of five different regions, from 71 HNSCC patients who had not been treated with anti-EGFR therapy. In seven cases corresponding lymph node metastases were also available for comparative analyses. We also determined the mutational status of tyrosine kinase (TK) domain (exon 19 and 21) and the extracellular deletion mutation (vIII) of EGFR, the KRAS mutation at codon 12 and the presence of HPV infection. Eight of the 71 cases (11.3%) showed EGFR gene amplification (most of them localized into the hypopharyngeal region) and the increased gene copy number (amplification+polysomy) was 43.7%. Despite pronounced intratumoral heterogeneity of EGFR protein expression being found, the high EGFR expression correlated with poor prognosis. On the other hand, the phosphorylation of EGFR was associated with prolonged survival. No mutations in the TK domain of EGFR were found in any of the HNSCC patients and only two cases were KRAS mutant at codon 12. We detected vIII deletion mutation of EGFR in 21% of the samples, but there was no statistically significant correlation between the presence of vIII mutant form and patient survival. EGFR vIII mutation was, however, associated with increased gene copy number. Fourteen of 71 cases (19.7%) were HPV-positive and the incidence of infection showed a decreasing tendency from the oral cavity towards the larynx. Interestingly, in contrast to previous findings, we could not observe improved survival in HPV-positive patients compared to non-infected patients, most probably due to the fact that the majority of these HNSCC patients were smokers and alcohol consumers. In conclusion, we found that increased EGFR protein levels and gene copy numbers (not gene amplification alone) have prognostic significance in the investigated HNSCC patient population. However, the relatively high incidence of the EGFR-vIII mutant form warrants careful therapeutic decision-making when choosing between different anti-EGFR treatment options.