The present invention relates to the field of cancer treatment, in particular to the treatment of carcinoma in situ bladder cancer and the provision of pharmaceutical compositions for use in the treatment thereof. The pharmaceutical compositions of the present invention comprise imiquimod, at least one pharmaceutically acceptable excipient, at least one organic acid and at least one thermo-sensitive agent. The present invention further relates to methods of treatment for carcinoma in situ bladder cancer and methods of administering the invention pharmaceutical composition.