This was a retrospective study in which the authors selected (unclear what the selection criteria was) 64 patients with primary urothelial malignancy and 6 patients with normal bladder mucosa as a control group. pT1/Ta specimens were obtained from TURBT while pT2+ samples were obtained from RC specimens. IHC was completed on all these specimen – presence or absence of EGFR on IHC was classified as 0 (not present or <10% staining), 1 (minimal staining and >10% of tumor cells stained), 2 (moderate staining and >10% of cells), 3 (strong staining and >10% of tumor cells). Patients with 2-3 score were considered high EGFR expression.
Of the 64 patients, 50% were pT2, 10% pT3/4, and rest were pTa/pT1. In the 6 normal bladder specimens, there were 4 patients with no staining and 2 patients with a score of 1 (weak EGFR). In the bladder cancer specimens, 83% had a score of 1 while 17% had a score 2+. While there is weak staining in all the stages of bladder cancer, the proportion with high EGFR expression increased with pT stage.
Based on this single series, they find an association between EGFR mutation and pT stage at treatment. However, this study is a cross-sectional analysis and does not associate EGFR with disease progression or response to therapy. As such, it is unclear if this is an association or a causative mutation. There are numerous genomic alterations seen with more aggressive cancer, but that doesn’t imply causation.
Presented by: Walid Kerkeni
Written by: Thenappan Chandrasekar, MD, Clinical Fellow, University of Toronto, twitter: @tchandra_uromd, at the 37th Congress of Société Internationale d’Urologie - October 19-22, 2017- Lisbon, Portugal