EP031/#958 Is the extemporaneous pathological examination reliable for the evaluation of surgical margins during conservative treatment for breast cancer?

Objectives

We aim to compare the performance of the extemporaneous pathological examination (EPE) with the definitive pathology examination (DPE) of the surgical margins in conservative surgery for breast cancer.

Methods

It is a retrospective single-center study including all the breast cancer patients who underwent a conservative breast surgery with EPE of the surgical margins in our department of gynecology and obstetrics from 2007 to 2017. The uninterpretable samples because totally necrotic, crushed, electro-coagulated, and/or poorly preserved were excluded. We did evaluate the performances of the EPE of the surgical margins by calculating the sensitivity, specificity, false-positive (FP), false negative (FN), positive predictive value (PPV), negative predictive value (NPV), diagnostic efficacy, and the Youden index.

Results

The EPE was performed 366 times for the evaluation of surgical limits. DPE objectified 279 healthy limits (76.2%) and 87 tumoral limits (23.8%). Of the 366 EPE carried out, the EPE was concordant with the final examination in 321 cases and discordant in 45 cases including 27 FN and 18 FP. The FN rate was 4.9%. The statistical analysis has shown that the EPE for the evaluation of the surgical limits had a sensitivity of 68.97% and a specificity of 93.55%. The positive and negative predictive values were 76.92% and 90.63% respectively. The diagnostic efficiency of the EPE for the surgical margins in conservative breast surgery was 87.70% and the Youden index was 0.63.

Conclusions

Regarding the evaluation of the surgical margins in conservative breast surgery, the EPE has a low sensitivity and a high rate of false negatives.