Dummy run of quality assurance program in a phase 3 randomized trial investigating the role of internal mammary lymph node irradiation in XXXX @entity1 : korean radiation oncology group 08-06 study.

@entity1 @entity0 @entity1161 @entity487 @entity1445 @entity489
PURPOSE: The  Korean Radiation Oncology Group (KROG) 08-06 study protocol allowed @entity1161 ( @entity1161 ) technique to include or exclude @entity0 @entity1 from receiving @entity1161 to the internal mammary lymph node (IMN). The purpose of this study was to assess dosimetric differences between the 2 groups and potential influence on clinical outcome by a dummy run procedure. METHODS AND MATERIALS: All participating institutions were asked to produce @entity1161 plans without irradiation ( @entity487 ) and with irradiation to the IMN ( @entity489 ) for 1 breast-conservation treatment case (breast-conserving surgery [BCS]) and 1 mastectomy case (modified radical mastectomy [MRM]) whose computed tomography images were provided. We assessed interinstitutional variations in IMN delineation and evaluated the dose-volume histograms of the IMN and normal organs. A reference IMN was delineated by an expert panel group based on the study guidelines. Also, we analyzed the potential influence of actual dose variation observed in this study on @entity1 survival. RESULTS: Although physicians intended to exclude the IMN within the @entity1161 field, the data showed almost 59.0% of the prescribed dose was delivered to the IMN in @entity487 . However, the mean doses covering the IMN in @entity487 and @entity489 were significantly different for both cases (P<.001). Due to the probability of @entity1445 in @entity487 , the estimated gain in 7-year disease-free survival rate would be reduced from 10% to 7.9% for BCS cases and 7.1% for MRM cases. The radiation doses to the ipsilateral lung, heart, and coronary artery were lower in @entity487 than in @entity489 . CONCLUSIONS: Although this dummy run study indicated that a substantial dose was delivered to the IMN, even in the nonirradiation group, the dose differences between the 2 groups were statistically significant. However, this dosimetric profile should be studied further with actual @entity1 samples and be taken into consideration when analyzing clinical outcomes according to IMN irradiation.
