When Is CT-Based Postoperative Seroma Most Useful to Plan Partial Breast Radiotherapy? Evaluation of Clinical Factors Affecting Seroma Volume and Clarity

The optimal time to obtain the planning CT scan for PBI is within 8 weeks after surgery. During Weeks 9-14, the seroma might remain adequately defined in some patients; however, after 14 weeks, alternate strategies are needed to identify the PBI target. The lack of correlation between the seroma volume and tumor size suggests that the CT-based seroma should not be the sole guide for PBI target volume definition.