br These differences in breast cancer risk
These differences in breast cancer risk factors, tumour
characteristics, and clinical outcomes suggest that breast cancer arising in very young and young women may be a distinct clinical entity. There is only limited data about the clinicopathological differences and outcomes between these subgroups.
The purpose of this study was to compare the clinicopatholog-ical characteristics and long-term clinical outcomes between the YWBC and VYWBC subgroups and present the evidence that younger age presents a worse prognosis.
Patients and methods
The current study was performed in accordance with the Research Ethics Committee of the National Institute of Oncology, Hungary (NIO). Written informed consent was always obtained for data collection. The inclusion period was from 1 January 2000 through 31 May 2014. Data were collected from the prospectively led database of the NIO, Budapest. Patients aged 35 years were grouped into the VYWBC group, and patents aged between 36 and 45 years were grouped into the YWBC group in a prospectively led database.
According to the updated international European Society of Medical Oncology (ESMO) Clinical Practice Guidelines for diagnosis, treatment and follow-up, all patients received multimodality oncology treatments and a follow-up at the NIO during the inves-tigation period [20e25]. The diagnosis of breast cancer was based on clinical examination in combination with imaging (mammo-gram, breast and regional Solasodine node ultrasound) and was confirmed via pathological (core biopsy or fine-needle aspiration cytology) assessment. MRI was used in most cases because the sensitivity of a mammogram is low in these populations due to the increased density of a young woman's breasts . MRI was also used in cases of breast implants, invasive lobular carcinoma (ILC), the suspicion of multifocality/multicentricity, or large discrep-ancies between conventional imaging and the clinical examination.
For surgical procedures, breast-conserving surgery (BCS), mas-tectomy, and sentinel lymph node biopsy (SLNB) with the dual radio-colloid/blue dye technique were used. In sentinel lymph node (SLN)-positive cases or for clinically positive axillary lymph nodes, axillary lymph node dissection (ALND) was performed. In the case of BCS, palpable tumours were resected via a wide excision, and non-palpable tumours were resected via a wide excision using the radio-guided occult lesion localization (ROLL) technique, with a minimum microscopic surgical margin of 1 mm for both invasive and in situ breast cancers. Postoperative pathological assessments included the number, location and size of the tumours removed, the total number of removed and positive lymph nodes, and the extent of metastases in the lymph nodes, such as isolated tumour cells, micrometastases (0.2e2 mm) and macrometastases. The report included the histological type and grade of the tumour, evaluation of the resection margins, vascular invasion, and a biomarker analysis, which included an immunohistochemical (IHC) evaluation of oestrogen receptors (ERs), progesterone receptors (PRs) and HER2 gene expression. HER2 gene amplification for tu-mours with an ambiguous (2þ) IHC score was evaluated using a fluorescent in situ hybridization (FISH) technique. The institutional breast cancer classification into surrogate intrinsic subtypes was based on the IHC assessment of ER, HER2 and Ki67, with a 20% cut-off during the investigation period. Surrogate breast cancer sub-types were classified according to the description of Perou et al. For the purposes of prognostication and treatment decision making, tumours were grouped into surrogate intrinsic subtypes, as defined by routine histology and IHC data .