There exists the controversy about internal mammary radiation. Multiple studies consistently show that a significant minority of patients with breast cancer have pathologic IMN involvement, and the risk of IMN involvement increases in patients with medial tumors and/or positive axillary nodes. Some recommend lymphoscintigraphy to identify such patients. While it seems reasonable based on these data to consider IMN irradiation for patients with medial tumors and/or positive axillary nodes, evidence directly linking IMN treatment to a survival benefit is not currently available. Randomized trials evaluating IMN dissection did not show a survival benefit, although they were largely underpowered, and retrospective studies evaluating patients with versus without IMN treatment have shown mixed results.
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