Identification of intraductal component by core-biopsy in invasive breast cancer and its impact on pCR achievement.

Abstract

e12554 Background: Core biopsy is considered to be a highly accurate method of gaining a preoperative histological diagnosis of invasive breast cancer (IBC). Intraductal component (IC) is often an accompanying element of IBC. Due to the growing interest in the use of minimally invasive interventions in IBC treatment, in particular vacuum-aspiration biopsy, the accurate determination of the presence of an IC before surgery becomes crucial, since the presence of IC is an exclusion criterion in many trials. Methods: We retrospectively analyzed data from 505 patients treated in 2020-2022 for whom information about diagnostic core biopsy and postoperative histology were available with an indication of IC presence. 274 patients received neoadjuvant systemic therapy (NST) and we assessed the role of IC in achieving pCR in this subgroup. Results: In the overall population (505 pts), intraductal component was found in 167 (33.1%) pts by core-biopsy and in 294 (58.2%) pts on postoperative histology. For the overall population, sensitivity was 44.56% (95% CI 38.79 to 50.44%), specificity was 82.94% (95% CI 77.17to 87.75%), positive predictive value was 78.44% (95% CI 72.47 to 83.42%), negative predictive value was 51.78% (95% CI 48.79 to 54.75%) and false negative rate was 55.4%. The presence of an intraductal component was significantly associated with the status of receptors on the surface of tumor according to core-biopsy (HR+/HER2- = 123 from 347 pts, HER2+ = 32 from 84 pts, HR-/HER2- = 15 from 74 pts. p=0.003) and according to postoperative histology with exception of patients achieved pCR (HR+/HER2- = 66 from 102 pts, HER2+ = 9 from 18 pts, HR-/HER2- = 12 from 33 pts. p=0.014). In the population without NST (231 pts), intraductal component was found in 85 (36.7%) pts by core-biopsy and in 188 (81.4%) pts on postoperative histology. For this population, sensitivity was 44.15% (95% CI 36.93 to 51.56%), specificity was 95.56% (95% CI 84.85 to 99.46%), positive predictive value was 97.65% (95% CI 91.38 to 99.39%), negative predictive value was 29.05% (95% CI 26.22 to 32.06%) and false negative rate was 55.8%. In the population which underwent NST (274 pts), intraductal component was found in 81 (29.6%) pts by core-biopsy and in 106 (38.8%) pts on postoperative histology. For this population, sensitivity was 45.28% (95% CI 35.59 to 55.25%), specificity was 79.76% (95% CI 72.88 to 85.56%), positive predictive value was 58.54% (95% CI 49.47 to 67.06%), negative predictive value was 69.79% (95% CI 65.66 to 73.63%) and false negative rate was 53.7%. pCR rate was 44.3% (121 pts). Presence of intraductal component in core-biopsy specimen did not significantly impact pCR achievement (p=0.374). Conclusions: Core-biopsy is not very effective tool in diagnosis of intraductal component preoperatively. pCR achievement is not dependent on presence of IC in core-biopsy specimen. Presence of IC is significantly associated with receptor status of the tumor.