S. Costa (Porto, Portugal)
Instituto Portugues de Oncologia - PortoAuthor Of 1 Presentation
81P - Is there a benefit for nodal evaluation as part of the post-lumpectomy imaging study before Radiotherapy?
Abstract
Background
Post-lumpectomy imaging (PLI) studies can contribute to the detection of residual tumor before radiotherapy (RT) is started. However, there is no solid evidence it confers any significant clinical benefit, which explains why some centers don’t integrate it. In our institution, most patients undergoing breast-conserving surgery (BCS) do mammogram + breast/axillary US. US allows to study regional nodal breast areas and detect nodal residual disease. However, the lack of studies that include US as an integral exam of PLI leads to the paucity of data regarding its value. This study intends to evaluate the value of PLI before adjuvant RT regarding the nodal regional investigation in women after BCS.
Methods
Retrospective study. Included patients after BCS, with negative margins, referred to our RT department between 01/2018 and 12/2019. Routine digital mammogram and breast and axillary US performed between surgery and RT in all patients. Imaging findings divided into suspect and not suspect. Clinicopathological and demographic information was collected and analyzed using IMB® SPSS® v26.
Results
1262 breasts (1252 woman) were included, with a mean age of 57.2 (±11.0) years. Most tumors were infiltrating ductal carcinoma associated with ductal carcinoma in situ (54.8%), grade II or III (88.3%), pT1 (60.1%), and hormone receptors positive (86.4%). The median time interval between surgery and PLI was 128.3 (±68.2) days. Among the 1262 breasts analyzed, 30 (2.4%) had suspicious findings for nodal residual disease and 24 were evaluated with cytology. Only 1/24 (4.1%) was positive for malignancy, 0.1% cases overall. No further statistical analysis was possible. Our results show the vast majority corresponds to benign lymph nodes. Only 0.1% of the overall cases proved to be malignant. The low positive predictive value of 4.1% may result from the major limitation radiologists face distinguishing malignant and reactional changes. Further nodal investigation won’t be necessary for almost every patient after BCS.
Conclusions
In most cases with suspicious findings for nodal disease, no findings for malignancy were found. Most patients had post-surgery reactional changes, and histologic confirmation may be mitigated.
Legal entity responsible for the study
André Pires.
Funding
Has not received any funding.
Disclosure
All authors have declared no conflicts of interest.