Accuracy of breast MRI in patients receiving neoadjuvant endocrine therapy: comprehensive imaging analysis and correlation with clinical and pathological assessments

Abstract

Purpose To assess the accuracy of magnetic resonance imaging (MRI) measurements in locally advanced oestrogen receptor-positive and human epidermal growth factor receptor 2-negative breast tumours before, during and after neoadjuvant endocrine treatment (NET) for evaluation of tumour response in comparison with clinical and pathological assessments. Methods This prospective study enrolled postmenopausal patients treated neoadjuvant with letrozole and exemestane given sequentially in an intra-patient cross-over regimen. Fifty-four patients were initially recruited, but only 35 fulfilled the inclusion criteria and confirmed to participate with a median age of 77. Tumours were scanned with MRI prior to treatment, during the eighth week of treatment and prior to surgery. Additionally, changes in longest diameter on clinical examination (CE) and tumour size at pathology were determined. Pre- and post-operative measurements of tumour size were compared in order to evaluate tumour response. Results The correlation between post-treatment MRI size and pathology was moderate and higher with a correlation coefficient (r) 0.64 compared to the correlation between CE and pathology r = 0.25. Post-treatment MRI and clinical results had a negligible bias towards underestimation of lesion size. Tumour size on MRI and CE had 0.82 cm and 0.52 cm lower mean size than tumour size measured by pathology, respectively. Conclusions The higher correlation between measurements of residual disease obtained on MRI and those obtained with pathology validates the accuracy of imaging assessment during NET. MRI was found to be more accurate for estimating complete responses than clinical assessments and warrants further investigation in larger cohorts to validate this finding.

Prognostic value of breast MRI characteristics before and during neoadjuvant endocrine therapy in patients with ER+/HER2- breast cancer

“…The agreement in radiologic response was substantial between the radiologists. Remarkably, three patients showed a radiologic complete response, two of whom had a poor prognosis (PEPI-2/3) at histopathological evaluation, a similar observation made by Reis et al 9 All three patients were diagnosed with an ILC, which are known to grow diffusely without significant desmoplastic reaction ( i.e. show non-mass enhancement), and are often ill-defined on imaging.…”

“…Similar to our study, however, several patients (7 out of 35) were discordantly classified as complete responders on MRI with residual disease at pathology. 9 …”

Correlation between MRI morphological response patterns and histopathological tumor regression after neoadjuvant endocrine therapy in locally advanced breast cancer: a randomized phase II trial

“…The 50 eligible participants had to be postmenopausal to benefit from neoadjuvant aromatase inhibitors (NAAI) with no or limited distant metastasis. The inclusion and exclusion criteria are given in Supplementary † [ 14 ]. Patient selection for neoadjuvant treatment was determined by the multidisciplinary breast cancer team at the Akershus University Hospital.…”

“…Breast magnetic resonance imaging (MRI) is the most accurate and recommended modality, often considered as the gold standard [ 1 , 13 ]. However, tumor extent is often more challenging to assess after neoadjuvant therapy and MRI might both over- and underestimate the residual tumor size [ 14 ]. There are two main patterns of tumor size response following neoadjuvant systemic therapy: some tumors can show a concentric shrinkage pattern, while others may fragment into scattered islands of tumor cells embedded in connective and fatty tissue [ 15 , 16 ].…”

The Present and Future of Neoadjuvant Endocrine Therapy for Breast Cancer Treatment

“…Estimating final pathology size after treatment is crucial when employing neoadjuvant therapies, since it allows a surgical approach to be planned. Correlation between post-treatment size and final pathology size is better with MRI than with clinical exploration [ 67 ], but no studies comparing MRI accuracy with US or US-mammography are available in the NET setting, although in the NCT scenario some authors have found US to be as accurate as MRI [ 68 ]. On the other hand, MRI could provide not only data on responsiveness to therapy but could also predict which patients would benefit most from it.…”