MONDRIAN

This is a one-arm, single site, open-label phase II study. Patients will be enrolled in the screening step at the start of the second line of chemotherapy, and will undergo blood draws for ctDNA detection. Patients for whom ctDNA was successfully detected and found informative by the study executive board could then be included in the interventional step when starting a new line of therapy.;ctDNA will be quantified using the customized test, at baseline and day 15 (+/- 3 working day) of cycle #1, and results will be made available before the cycle 2 Day 1, together with a treatment management recommendation by the Study Executive Board (continuation or discontinuation of the corresponding chemotherapy)