A catheter treatment apparatus comprises an elongate tubular member and an expandable support. The expandable support comprises a radioactive substance to treat cancerous tissue and is configured to expand from a narrow profile for insertion to a wide profile to engage and treat tissue remaining after resection. The expandable support can be sized to fit within a volume of removed tissue to place the radioactive substance in proximity to the capsule and remaining tissue, to spare the capsule and proximate nerves and vessels to treat tissue in proximity to the capsule. The elongate tubular member may comprise a channel such as a lumen to pass a bodily fluid such as urine when the expandable support engages the tissue to treat the patient for a plurality of days. The treatment apparatus can be used to resect and diagnose tissue concurrently. Based on the diagnosis, targeted segmental treatment may be given.