br Written informed consent was obtained from all patients a
Written informed consent was obtained from all patients according to the Declaration of Helsinki principles. MR examinations were per-formed in the second week of menstrual SCH 58261 in case of premenopausal women.
Definitive lesion characterization was obtained by the histological examination and surgical specimen in patient with breast cancer, by histological examination in suspected breast lesions on mammography or ultrasonography and by 12 months follow-up evaluation in negative MR exams. Twelve month follow-up evaluation consisted of clinical, mammographic and ultrasound examinations.
As result, we finally selected a total of 82 breast cancer affected patients (34 premenopausal, 48 postmenopausal).
Inclusion criteria for the molecular cancer subtype evaluation were:
- Unilateral lesion detected at DCE-MRI;
- Absence of BRCA1/2 gene mutation;
- Histologically proven cancer.
2.2. Receptor expression analysis
In order to classify cancer subtypes, ER, PR, HER2 and Ki67 ex-pression was assessed by immuno-histochemical analysis performed on formalin-fixed, paraffine-embedded tissue sections [36–38]. European Journal of Radiology 113 (2019) 148–152
As already reported by M.Y. Kim et al. , the ER and PR status was evaluated using Allred score, and considered positive when the total score (sum of proportion and the immune-intensity score) was ≥
MR examinations were performed on a 1.5 TMR device (Achieva, Philips Medical Systems, Best, The Netherlands) by using a four channel breast coil. The protocol consisted of:
with 3-mm slice thickness and without gaps, 3 averages, turbo factor
• Three-dimensional (3D) dynamic, contrast-enhanced (CE) T1-weighted high resolution isotropic volume (THRIVE) sequences (TR/TE = 4.4/mm3);
SENSE factor 1.6, 6 dynamic acquisitions, resulting in 1.5-mm3 isotropic voxels, a dynamic data acquisition time of 1 min 30 s, and a total se-quence duration of 9 min). Gadobutrol (Gadovist, Bayer Shering, Berlin, Germany) was intravenously injected at a dose of 0.1 mmol/kg of body weight and flow rate of 1.5 ml/s followed by 20 ml of saline solution.
After the dynamic series, image subtraction sequences were created in order to suppress the signal from fat tissue and enhancing lesions were identified on the subtracted images.
All MRI data were transferred to and analyzed on a diagnostic workstation equipped with dedicated software for MRI (View-ForumR5.1 V1L1 2006). Two radiologists with more than 5 years of experience in the field of breast MRI retrospectively evaluated all subtracted enhanced images for classifying BPE. In order to standardize the image interpretation, the third dynamic sequence (about after 180 s from the intravenous injection of contrast material) was used for this purpose. BPE was classified into 4 categories: minimal (< 25% of glandular tissue enhancement), mild (25%–50% enhancement), mod-erate (50%–75% enhancement) and marked (75–100% enhancement). In case of suspected MR lesions, BPE was evaluated on the contralateral breast in order to avoid any increased vascularization caused by breast cancer. The post-processing mean duration time was of about 10 min for MR post-contrast imaging.
2.5. Statistical analysis
Patients were classified into 5 groups of cancer subtypes according to St Gallen International Expert Consensus on the Primary Therapy of Early Breast Cancer 2013 : Luminal A, Luminal B HER2 negative, Luminal B HER2 positive, HER2 positive non luminal, triple negative. The χ2 test was used in order to evaluate the significance of BPE type distribution among the five groups of tumor subtypes. The χ2 test
G. Dilorenzo, et al.
was also performed for investigating the distribution of the five breast cancer subtypes among every single BPE type.
A multivariate regression analysis including patient age, meno-pausal status and tumor diameter was used searching for any con-founding effect to BPE measurement and distribution among the dif-ferent groups of lesions. A dichotomized approach on BPE with logistic regression was also performed.
Cohen's kappa statistics was used in order to assess inter-observer agreement for classifying BPE. A k value of m6re than 0.81 was con-sidered to represent almost perfect agreement and values of 0.61–0.80 and 0.41–0.60 to represent substantial and moderate agreement, re-spectively. All calculations were performed using NCSS2007® statistical soft-ware.
3.1. BPE distribution among tumor subtypes
Mild BPE pattern was significantly more prevalent (p = 0.0001) than other BPE types only in the luminal B (HER-) tumors (Fig. 1). No other significant distribution difference was found in other breast cancer subtypes. In fact, BPE had casual distribution into the remaining four groups, with mild and moderate types being respectively the first and second most common patterns, and marked BPE the rarest one in almost all categories. The only exception was represented by triple negative group, in which an inversion of this trend occurred, with moderate and marked BPE prevailing on minimal and mild (Table 1; Fig. 2).