Best practices in epidermal growth factor receptor T790M testing for advanced non-small-cell lung cancer in Hong Kong

The T790M mutation in the epidermal growth factor receptor gene causes most acquired resistance to firstor second-line epidermal growth factor receptor- tyrosine kinase inhibitors in advanced non-smallcell lung cancer. The results of T790M testing can guide subsequent treatment. Despite the availability of guidelines from international organisations, T790M testing practices in Hong Kong must be streamlined and adapted to the Hospital Authority setting. To address this issue, a panel of experts in oncology and pathology met for discussion of key topics regarding T790M testing practices in Hong Kong, including the appropriate timing of testing and re-testing, as well as optimal testing methods. All panel members voted on the results of the discussion to achieve consensus. Items supported by a majority vote were adopted as consensus statements regarding current best practices for T790M testing in Hong Kong. Among the topics discussed, the panel agreed that T790M testing should be initiated upon radiological progression, including symptomatic disease progression or central nervous system-only progression. The experts also preferred initial testing with liquid biopsy, using the widely available digital polymerase chain reaction platform. This document provides the final consensus statements, as well asa testing and treatment workflow, for clinicians in Hong Kong to use as guidance in T790M testing.