System for treating cancer or tumors by thermotherapy, comprising an expandable implant device, an excitation catheter and an electric power source, wherein the implant device is configured to circumferentially subtend a vessel upon expansion of the implant device in said vessel, the implant device comprising a set of cross-connected conductors forming a circumferential structure with openings in between the conductors, said openings having a minimal opening distance of at least 2 mm when the implant device is expanded, wherein the excitation catheter comprises a longitudinal shaft with a distal end a proximal end, and a longitudinal body in between, whereby the catheter comprises a longitudinal axis along the longitudinal shaft, and whereby the catheter further comprises an emitter coil at or near the distal end, and whereby the longitudinal body of the catheter further comprises a wiring lumen comprising electrical wiring extending from the distal end to the proximal end, and whereby the electrical wiring is connected at or near the distal end with the emitter coil, and wherein the electric power source is configured to be connected to the wiring via the proximal end of the catheter shaft for the generation of a time-varying magnetic field with the emitter coil, further comprising a set of bioprobes, each bioprobe comprising a magnetic susceptor and at least one ligand, wherein the implant device comprises cavities at an outer surface of the implant device, said cavities provided with the set of bioprobes, and said cavities closed off with a thermodegradable cover, such that the bioprobes are released from the cavities upon heating of the implant device. wherein the implant device is configured to circumferentially subtend a vessel upon expansion of the implant device in said vessel, the implant device comprising a set of cross-connected conductors forming a circumferential structure with openings in between the conductors, said openings having a minimal opening distance of at least 2 mm when the implant device is expanded, wherein the excitation catheter comprises a longitudinal shaft with a distal end a proximal end, and a longitudinal body in between, whereby the catheter comprises a longitudinal axis along the longitudinal shaft, and whereby the catheter further comprises an emitter coil at or near the distal end, and whereby the longitudinal body of the catheter further comprises a wiring lumen comprising electrical wiring extending from the distal end to the proximal end, and whereby the electrical wiring is connected at or near the distal end with the emitter coil, and wherein the electric power source is configured to be connected to the wiring via the proximal end of the catheter shaft for the generation of a time-varying magnetic field with the emitter coil, further comprising a set of bioprobes, each bioprobe comprising a magnetic susceptor and at least one ligand, wherein the implant device comprises cavities at an outer surface of the implant device, said cavities provided with the set of bioprobes, and said cavities closed off with a thermodegradable cover, such that the bioprobes are released from the cavities upon heating of the implant device.