PhD Scientific Days 2022

Pathology and Oncology III. (Poster discussion will take place in the Aula during the Coffee Break)

Tumor-Stroma Ratio in Breast Cancer: Comparison of Findings in Core Biopsies and Resection Specimens

Text of the abstract

Introduction: Tumor-stroma ratio (TSR) is considered an important prognostic and predictive factor in several tumor types. In our previous study we found that the TSR of the core biopsy can be used as a predictive factor in planning neoadjuvant chemotherapy.
Aims: We aim to analyse whether TSR measured on breast cancer core biopsy is representative of the whole tumor and how is it associated with prognosis. Only few scientifically substantiated data describe the scoring method in core biopsies compared with resections specimens, thus we analysed different scoring methods and their reproducibility and aimed to find the most suitable method.
Methods: 178 core biopsies and the corresponding resection specimens from 174 patients treated with primary surgical therapy were investigated. Patients with median age of 63.5 year (28-90) were diagnosed between 2010-2021. Clinicopathological data were obtained from the medical database of Semmelweis University (Permission SE RKEB: 244/2019). Recurrence-free survival (RFS) was defined as the time from surgery to the occurrence of any breast cancer related event. Hematoxylin-eosin-stained, digital slides were analyzed based on the methodology recommended by Mesker et al., at x100 and x200 magnification by two trained scientists (ZsK-Budapest and SH-Leiden University). On the most stroma rich area TSR was visually determined by tenfold percentage steps and the cases were divided into two groups: ≤50% stromal area as stroma low (SL) and >50% stromal area as stroma high (SH).
Results: The interobserver variability of TSR was low (core biopsy, x100: κ =0.91, x200: κ =0.79, resection specimen: x100: κ =0.89, x200: κ=0.73). Looking at the similarities of the scores in biopsy and resection specimen, the highest correlation was found using x100 magnification. Discrepancies were more frequent if the biopsy contained small amount of tumor or if the resection specimen had only one stroma high area. There were 21 recurrencies during the follow-up period. Among 162 (91%) hormone receptor positive (HR+) tumors stroma high cases were associated with significantly shorter RFS (p=0.046 at 60% cut-off point).
Conclusions: Based on our findings scoring TSR on core biopsies is reproducible and mostly representative of the whole tumor and can be used as a prognostic factor in HR+ cases.
Funding: 3.6.3-VEKOP-16-2017-00009