PHYSICIAN PATIENT-DRIVEN RISK ASSIGNMENT IN RADIATION ONCOLOGY - REALITY OR FANCY/

Purpose: Treatment plan optimization in radiation oncology entails des igning multiple x-ray beams to irradiate a tumor to a dose that will a chieve locoregional control while minimizing normal tissue complicatio ns, For some anatomical sites, it is possible to estimate tumor contro l probabilities (TCP) and normal tissue complication probabilities (NT CP) as a function of radiation dose, Thus, treatment plan optimization can be based on biologic end points rather than on dose calculations alone, Given multiple plans with different NTCPs and TCPs, a tradeoff must be made between maximizing TCP and maintaining an acceptable NTCP , How do physicians reach these decisions? Can the process be quantifi ed? Should patients participate in the process? Methods and Materials: Physicians and patients were asked to rank a series of treatment plan s having different combinations of TCP and NTCP, Responses were parame trized into a figure of merit (FM) equation which quantifies predilect ions of TCP and NTCP. Results: Physician-based FM equations are site- and patient-specific. Variations exist among physicians, but treatment plan selection is often conservative in accordance with the primum no n nocere dictum, FM equations generated from the responses of patients suggest that some patients may be willing to accept higher treatment toxicity in exchange for increased TCP. Conclusion: The term ''optimiz ed treatment plan'' contains inherently subjective criteria which refl ect one's willingness to accept treatment morbidity in exchange for pr obability of cure, These criteria may differ among patients and/or phy sicians, A quantifiable FM may permit the design of custom-made treatm ent plans that include physician and patient input, (C) 1997 Elsevier Science Inc.