56P - Agreement between predicted response by imaging methods and pathological response by RCB in breast cancer patients treated with neoadjuvant chemothe...
|Date||08 May 2014|
|Session||Welcome reception and Poster Walk|
|Topics|| Breast Cancer
Imaging, Diagnosis and Staging
|Citation||Annals of Oncology (2014) 25 (suppl_1): i19-i20. 10.1093/annonc/mdu068|
C. Schermann1, B. Zurl2, P. Regitnig3, F. Moinfar1, F. Symmans4, V. Bjelic-Radisic5, P. Schrenk6, F. Peintinger1
Residual Cancer Burden (RCB) is a new measurement that quantifies the extent of residual disease after neoadjuvant chemotherapy for breast cancer combining both primary tumor bed features and axillary lymph node features. We evaluate the tumor response measured by routine imaging and examine the agreement between predicted tumor response and RCB.
In a prospective pilot study evaluating RCB in HER2 negative breast cancer, mammography, sonography and MRI were used at diagnosis and after completion neoadjuvant chemotherapy to assess tumor response for optimal surgical planning. RCB was classified as RCB-0 (pathologic complete response, pCR) or as Residual Disease (RCB-I, RCB-II, RCB-III). Tumor response by imaging was classified according to the RECIST criteria (Response Evaluation Criteria In Solid Tumors). We examined the agreement between predicted tumor response (in the breast and in the axilla) by imaging and actual pathological response by RCB.
A total of 24 patients were included. Two patients were staged as T1N0, 1 patient as T1N1, 8 as T2N0, 11 as T2N1 and 2 patients as T3N1 at diagnosis. Eight patients were treated by mastectomy and 16 had a breast conserving treatment. RCB-0 (pCR) was observed in 8 patients (33%), RCB-I in 3 patients (13%), RCB-II in 12 patients (50%) and RCB-III in one patient (4%). Tumor response according to RECIST was CR (complete response) in 8 patients (33%), PR (partial response) in 8 patients (33%) and SD (stable disease) in 8 patients (33%). The overall agreement between imaging and RCB was K = 0.45. Preliminary data show a higher agreement between MRI and RCB in comparison to mammography (K = 0.37 vs. K = 0.28). When proportions were analyzed, only the agreement between PR and RCB-II was lower than 60%.
The agreement between the pathological response evaluation using RCB categories and the radiological evaluation using RECIST criteria was moderate indicating the need for improvement in preoperative imaging. RCB may be used as a tool for testing predictive accuracy of future imaging technologies.
All authors have declared no conflicts of interest.