(I) An etoposide, or analogue of an etoposide, for use in a treatment comprising the inhibition of and/or prevention of the growth and/or survival of cancer stem cells. An etoposide analogue of formula (I) wherein X is selected from O, NH and S n is 0, 1 or 2 and R1 and R2 are independently selected from the group consisting of H, methyl or ethyl, or together form a group CR3R4 wherein R3 and R4 are independently selected from the group consisting of H, methyl and ethyl, or a pro-drug, derivative solvate or salt thereof, for use in a treatment comprising the inhibition of and/or prevention of the growth and/or survival of cancer stem cells is outlined. Preferably the cancer disease is selected from a chemo or radiation therapy resistant cancer, a metastatic cancer, an aggressive cancer, a refractory cancer, a recurrent cancer or a non-resectable tumour. In particular, the cancer is a drug resistant cancer disease characterised by a tumour expressing a protein of the multidrug resistant ABC transporter type, preferably by a tumour having the MDR1 phenotype.
