A pharmaceutical composition for inhibition of tumors containing an effective dose of a compound of formula (I), wherein Q is CO, CH(OH) or C(OH)CH3, M1 is halogen, M2 is halogen or hydrogen, p is 0 or 1 and one of the groups x and x' is hydrogen and the other is a hydroxyalkyl, methoxyalkyl, ethoxyalkyl or oxoalkyl wherein the alkyl contains 2-9 carbon atoms, the group x preferably being in the exo position.