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

Abstract

Purpose To correlate MRI morphological response patterns with histopathological tumor regression grading system based on tumor cellularity in locally advanced breast cancer (LABC)-treated neoadjuvant with third-generation aromatase inhibitors. Methods Fifty postmenopausal patients with ER-positive/HER-2-negative LABC treated with neoadjuvant letrozole and exemestane given sequentially in an intra-patient cross-over regimen for at least 4 months with MRI response monitoring at baseline as well as after at least 2 and 4 months on treatment. The MRI morphological response pattern was classified into 6 categories: 0/complete imaging response; I/concentric shrinkage; II/fragmentation; III/diffuse; IV/stable; and V/progressive. Histopathological tumor regression was assessed based on the recommendations from The Royal College of Pathologists regarding tumor cellularity. Results Following 2 and 4 months with therapy, the most common MRI pattern was pattern II (24/50 and 21/50, respectively). After 4 months on therapy, the most common histopathological tumor regression grade was grade 3 (21/50). After 4 months an increasing correlation is observed between MRI patterns and histopathology. The overall correlation, between the largest tumor diameter obtained from MRI and histopathology, was moderate and positive (r = 0.50, P-value = 2e-04). Among them, the correlation was highest in type IV (r = 0.53). Conclusion The type II MRI pattern “fragmentation” was more frequent in the histopathological responder group; and types I and IV in the non-responder group. Type II pattern showed the best endocrine responsiveness and a relatively moderate correlation between sizes obtained from MRI and histology, whereas type IV pattern indicated endocrine resistance but the strongest correlation between MRI and histology.

MRI-based tumor shrinkage patterns after early neoadjuvant therapy in breast cancer: correlation with molecular subtypes and pathological response after therapy

“…The classification and definition of TSP at MRI have not been consistently recognized and unified. The CS or non-CS patterns after NAT and further refinement of non-CS pattern at mid-NAT were commonly used [ 11 , 17 , 20 ]. Based on Fukada et al’s study [ 11 ], we developed four-category TSP and subdivided CS and DD pattern to suit early NAT response.…”

“…In our study, the DD pattern after early NAT tended toward pCR in HR + /HER2 − subtype, mainly at 1st-timepoint, independent of size change. Reis et al [ 20 ] reported that early fragmentation pattern after 2 months neoadjuvant endocrine therapy suggested effective treatment in ER + /HER2 − subtype. The DD pattern may be the early manifestation of HR + /HER2 − subtype response to NAT earlier than size reduction.…”

“…It has been observed that concentric and fragmented shrinkage patterns are more commonly observed in patients achieving pCR, while stable disease is noted in those who do not achieve pCR during the middle stage and after NAT [ 16 , 17 ]. Furthermore, analyses have demonstrated variations in TSP among different subtypes [ 18 – 20 ]. However, the understanding of TSP following early treatment (i.e., the first or second cycle of NAT) and their association with treatment response remains limited.…”

Quantitative DCE-MRI for prediction of pathological complete response prior to neoadjuvant systemic therapy

“…The tumour shrinking pattern was de ned as tumour regression on MRI compared to that at baseline after two courses of NST. Tumour regression was classi ed into 6 categories [9]: 0 (complete imaging response), I (concentric shrinkage), II (fragmentation), III (diffuse contrast enhancement), IV (stable disease), and V (progressive disease). The preoperative MRI residual tumour status was de ned as the evaluation of the presence of a tumour based on MRI after treatment completion.…”

Ultrasound-assisted carbon nanoparticle labeling of neoadjuvant chemotherapy for breast-conserving surgery in breast cancer

“…Preoperative neoadjuvant chemotherapy can allow some patients to regain the opportunity for surgery and reduce tumor staging in some patients (4). However, tumor regression following chemotherapy can be a concern, as the remaining tumor cells cannot be located even under a microscope in some patients (5). Moreover, illness assessment focuses on axillary lymph node examination after treatment (6).…”