In one embodiment, the invention provides a new design of nanocarrier compositions that release their therapeutic load specifically at intraperitoneal cancers' site. These nanocarriers are administered intraperitoneally and comprise a plurality of porous nanoparticulates that (a) are loaded with one or more pharmaceutically-active agents alone or in combination with imaging agents thus providing a theranostic value and (b) that are encapsulated by and that support a lipid bilayer which is disrupted upon contact with a reactive oxygen species generated within the environment of the cancer. In other embodiments, the invention provides methods of treatment and pharmaceutical compositions comprising nanocarriers as described herein.