Abstract 86P
Background
Frozen section (IFS) assessment enables intraoperative assessment of resection margins, however, its accuracy is subjected to interobserver variability. This study evaluated factors that affect efficacy of resection margin evaluation using IFS in a cohort of breast cancer patients and its impact on disease free and overall survival.
Methods
All patients presenting with primary operable breast carcinoma who received IFS between 2016 and 2018 at the Breast Health Centre of the Medical University Vienna were included in the study. Patients received standard adjuvant treatment as indicated by current guidelines. Data were collected retrospectively. Cox regression was used to test for a difference in survival between patients with incorrect and correct IFS.
Results
The study cohort consisted of 997 female patients with a mean age of 58.8 (± 12.9). IFS assessment was true positive in 222 cases (21.3%), false positive in 158 (15.2%), true negative in 629 (60.5%) and false negative in 31 cases (3%), translating into a sensitivity of 0.87 and a specificity of 0.8 of IFS. 152 patients (14.6%) received a follow up resection after a false positive IFS and in 5 cases (0.5%) a false negative IFS led to no follow up resection. 73 patients (7.3%) had at least 1 reoperation, with residual tumor tissue in 29 (39.7%) of these. Factors associated with incorrect IFS were intrinsic subtype luminal B HER2 negative (p<0.001), and refrainment from neoadjuvant treatment (p=0.002). Lymph node metastasis was associated with residual tumor in subsequent resection specimens (p=0.03). Correctness of IFS did not impact local recurrence (p=0.39), progression free survival (PFS; p=0.7) and overall survival (OS; p=0.17). Also, no difference was detected in true negative vs false negative IFS regarding PFS (p=0.6); but interestingly there was a difference in OS (p<0.001), in favor of patients with true negative IFS.
Conclusions
Our study shows that resection margin assessment using IFS does not affect local recurrence or progression free survival of breast cancer patients, regardless of its correctness. The results of our study indicate that intrinsic subtype has an impact on resection margin assessment and extended local surgery might not ameliorate adverse prognosis despite negative margins.
Legal entity responsible for the study
The authors.
Funding
Has not received any funding.
Disclosure
All authors have declared no conflicts of interest.