A fatty acid analogue of the general formula: R.sub.1-[x.sub.i-CH.sub.2].sub.n--COOR.sub.2, wherein R.sub.1 is: a C.sub.2-C.sub.24 alkene with one or more double bonds and/or with one or more triple bonds, and/or a C.sub.2-C.sub.24 alkyne, and/or a C.sub.1-C.sub.24 alkyl, or a C.sub.1-C.sub.24 alkyl substituted in one or several positions with one or more compounds selected from the group comprising fluoride, chloride, hydroxy, C.sub.1-C.sub.4 alkoxy, C.sub.1-C.sub.4 alkylthio, C.sub.2-C.sub.5 acyloxy or C.sub.1-C.sub.4 alkyl, and wherein R2 represents hydrogen or C.sub.1-C.sub.4 alkyl, and wherein n is an integer from 1 to 12, and wherein i is an odd number and indicates the position relative to COOR.sub.2, and wherein X.sub.i independent of each other are selected from the group comprising O, S, SO, SO.sub.2, Se and CH.sub.2, and with the proviso that at least one of the X.sub.i is not CH.sub.2, and or a salt, prodrug or complex thereof is used in the treatment and/or prevention of primary and secondary metastatic neoplasms.