[Use of genome-wide testing in oncology: French expert opinion based on the Delphi methodology].

In oncology, genome-wide testing is a major element in facilitating the implementation of precision medicine. However, current recommendations do not always specify the indication and utility of these tests according to the type of cancer. A national consensus approach based on a modified Delphi methodology was set up to provide expert opinion on the use of genome-wide testing in clinical practice in France. Four groups of experts - 4 each representing the following topics of interest - were defined: non-small cell lung cancer (NSCLC), breast cancer, melanoma, and cancer of unknown primary (CUP). In each group, assertions were formulated by a lead expert (8, 5, 7 and 6, respectively) and rated by five panellists involved in the management of these cancers, on a scale from 1 (strongly disagree) to 9 (strongly agree). Consensus was reached when 75% of the scores were above 7. In case of disagreement, the panellists were asked to justify their rate. In total, 24 statements reached consensus after two to four rounds of rating, depending on the group. While the experts advocated the routine use of genome-wide testing in the diagnostic management of NSCLC and CUP, they did not recommend the systematisation of these tests for breast cancer and melanoma. Nevertheless, access to innovation in France could soon remove certain barriers and allow greater standardisation of broad molecular screening in oncology.