Evaluation of the accuracy of the study on diverse techniques of planning radiotherapy of breast tumors

: The authors report the results of the analysis of several factors contributing to the accuracy of treatment planning in the radiation therapy of breast cancer. Different techniques (non-radiological vs CT-based) were used for the acquisition of patients' data; different methods (manual vs computerized) were employed for dose calculation. As for geometric parameters describing the external outline and target volume, mean differences were lower than 4%. Switching from a completely manual method to a CT-based one with computerized calculation, a 3.56% mean decrease in the value of reference isodose (p less than 0.01) was observed, together with a 3.87% mean increase in the estimated inhomogeneity (p less than 0.001). The non-CT-based outline of target volume exhibited geographic missing of inner portions of the target in 8/16 patients. Our results demonstrate that treatment planning procedures can be a significant source of clinically relevant inaccuracy, which may affect treatment outcome and tumor control.