A method for treating a tumor at least partially within an organ in a subject's body. The method comprises volumetrically compressing the tumor to increase a pressure within the tumor above a threshold level to cause ischemia of the tumor； and maintaining the pressure above the threshold level for a period sufficient to cause necrosis in the tumor. The method may include passing a tension member within the organ around a predetermined volumetric region encompassing at least a portion of the tumor. The method may include tightening the tension member to cause compression of the volumetric region, thereby directly increasing a pressure within the tumor. The method may include maintaining the increased pressure such that most or all tissues of the tumor undergo ischemia and/or necrosis resulting directly from the compression caused by the tightened tension member.
