Methods of treating bladder cancer

A method of treating bladder cancer in an individual or preserving bladder in an individual, comprising intravesically administering to the individual an effective amount of an oncolytic virus once per week for six weeks during an induction phase, and subsequently intravesically administering to the individual an effective amount of the oncolytic virus once per week for three weeks every three or six months during a maintenance phase, wherein the start of the induction phase and the start of the maintenance phase are separated by about three months or about six months, and wherein the oncolytic virus comprises a viral vector comprising a tumor cell-specific promoter operably linked to a viral gene essential for replication of the oncolytic virus, and a heterologous gene encoding an immune-related molecule.