ECP 2022 Abstract Book

Virchows Archiv (2022) 481 (Suppl 1):S1–S364 13 D. Damjanović*, J. Rajc, K. Marjanović, R. Gudelj, M. Bakula, R. Alaghehbandan *University Hospital Osijek, Croatia Background & objectives: Breast cancer is a heterogeneous dis- ease, with a spectrum of biological features and differences in clin- ical outcome. The aim of this study was to examine the prognostic factors of luminal breast cancer subtypes among Croatian breast cancer population. Methods: This is a large retrospective population-based study including 1127 primary breast cancer cases, during a six year period (2016–2020) in Osijek, Croatia. The clinico-pathologic and immunohistochemical (IHC) and in situ hybridization (ISH) data were extracted from pathology reports to examine the luminal subtypes A and B. The cross-tabulated statistics of the observed characteristics were performed between the two subtypes. Results: Luminal cancers comprised 86.9% (980/1127) of the total cohort, including 724 (64.2%) cases of luminal B and 256 (22.7%) luminal A. Age profile of Luminal A and B cancers were simi- lar (63.5 vs 62.3 years). Mean tumour size was higher in luminal B than luminal A cancers (19.6 vs 22.2 mm, p=0.03). Luminal B cancers were significantly associated with adverse prognostic features than luminal A cancer, including high histologic grade (14% grade III luminal B vs 3.5% luminal A, p<0.0001), vascular invasion (18% luminal B vs 7.5% luminal A, p<0.0001), and nodal metastasis (21.2% luminal B vs 15.1% luminal A, p=0.006). Conclusion: Luminal B is the most frequent subtype of breast cancer in Croatian patients. They were associated with adverse clinico-histologic parameters such as higher grade, vascular inva- sion, and nodal metastasis. Our findings suggest that, despite lack of molecular studies in routine practice, IHC/ISH-based typing are sufficient for prognostic and therapeutic stratifications in breast cancers. PS-01-024 Ki67 proliferative index in patients with early breast cancer and its association with clinicopathological factors D. Damjanović*, J. Rajc, E. Matuzalem Marinović, B. Dumenčić, R. Gudelj, M. Bakula, R. Alaghehbandan *University Hospital Osijek, Croatia Background & objectives: Standard cut-off for distinguishing low and high Ki67 index as a prognostic marker in early breast cancer do not exist. The aim of this study was to determine the role of Ki67 index and its association with other prognostic parameters. Methods: A large population-based retrospective study including 957 primary early breast cancers (pT2 or less) was conducted during a 5-year period (2016–2020) in Osijek, Croatia. The clinico- pathologic data were extracted from pathology reports. Multiple logistic regression analysis was used to evaluate the associations between Ki67 and other clinicopathological factors. Results: The median Ki67 was 30% (range 2–98%), with 251 (26.2%) patients had a Ki67 <20%. Triple-negative breast can- cers showed highest ki67 index (mean 72.7 ± 23.9%) followed by HER2-positive (mean 60.2 ± 21.3%) and luminal B cancers (mean 39.8 ± 19.9%) (p<0.0001). Metaplastic and medullary breast can- cers significantly showed higher Ki67 index compared to ductal carcinoma, NOS. Using a multivariable logistic regression with Ki67 (<20% vs. ≥20%) as binary dependent variable, younger age, positive nodal status, higher grading, negative HR status, and posi- tive HER2 status were shown to be significantly associated with a higher proliferative index (Ki67 ≥20%). Conclusion: Ki67 index is a valuable biomarker of breast cancer as higher ki67 correlates with more aggressive tumour biology. However, definition of low and high proliferation index itself is challenging. It is essential to interpret Ki67 indices carefully with regard to the own institutional values and other clinicopathologi- cal factors. PS-01-025 To determine the accuracy of axillary staging using ultra- sound-guided fine-needle aspiration cytology in breast cancer patients: a single institutional experience I. Aloglu*, M. Doğan, S. Aydın Aksu, F. Aker *Department of Pathology, Haydarpaşa Numune Training and Research Hospital, Turkey Background & objectives: Ultrasound-guided fine-needle aspi- ration cytology (US-FNAC) of axillary lymphadenopathy is a helpful tool in identifying candidates for axillary dissection and neoadjuvant chemotherapy for breast cancer patients. This study investigated the diagnostic value of evaluating the axillary lymph nodes with US-FNAC. Methods: Between 2011 and 2021, 284 cases who underwent the axillary US-FNAC procedure during the diagnosis of primary breast cancer and then underwent axillary / sentinel surgery were collected retrospectively. Cytological diagnoses and corresponding histological diagnoses were documented. Final histopathology was taken as gold standard. The diagnostic parameters, including sen- sitivity, specificity, positive (PPV), and negative predictive values (NPV), were calculated. Results: Hundred-fifty-two of 284 cases were evaluated as malig- nant cytology in FNAC. There were no malignant histopathologi- cal findings in 4 of them. Conversely, 132 cases were evaluated as benign cytology in FNAC. While 41 of them had malignant tumour metastases histopathologically, 91 of them did not have any malignancy findings. Overall sensitivity of lymph node FNAC was 78.3% and specificity was 95.7%. Positive predictive value (PPV) was 97.3% and negative predictive value (NPV) was 68.9%. Conclusion: Axillary FNAC is a diagnostic method that helps surgeons decide whether to perform sentinel node biopsies. This technique is favourable due to its minimally invasive nature. In addition, we suggest that FNAC can prevent unnecessary axillary dissection due to its high positive predictive value (PPV). The reason for the lower negative predictive value may be hypocellularity and micrometastasis. So FNAC has adequate sensitivity and high specificity in diagnosing axillary lymph node metastasis. PS-01-026 Predictive factors of lymph node metastasis in breast cancer patients: a Croatian population-based study Z. Radičević*, J. Rajc, D. Damjanović, R. Gudelj, M. Bakula, R. Alaghehbandan *University Hospital Osijek, Croatia Background & objectives: Breast cancers are heterogeneous groups of tumours, and its subtypes correlates with therapeutic response and overall survival. In this study, we assessed whether the subtype can predict the presence of nodal metastasis in a large cohort of breast cancer patients. Methods: A large population-based retrospective study includ- ing 1127 primary breast cancers was conducted during a 5-year period (2016–2020) in Osijek, Croatia. The clinico-pathologic data were extracted from pathology reports. The Pearson chi- square test was used to determine whether progesterone receptor (PR) status had an impact on the incidence of lymph node posi- tivity in oestrogen receptor (ER) positive patients. S67