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Evaluating the role of magnetic resonance imaging post‐neoadjuvant therapy for breast cancer in the NEONAB trial
Author(s) -
Murphy Caitlin,
Mukaro Violet,
Tobler Robert,
Asher Rebecca,
Gibbs Emma,
West Linda,
Giuffre Bruno,
BaronHay Sally,
Khasraw Mustafa
Publication year - 2018
Publication title -
internal medicine journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.596
H-Index - 70
eISSN - 1445-5994
pISSN - 1444-0903
DOI - 10.1111/imj.13617
Subject(s) - medicine , breast cancer , magnetic resonance imaging , neoadjuvant therapy , epirubicin , trastuzumab , breast mri , cancer , pathological , oncology , nuclear medicine , radiology , mammography
Background Magnetic resonance imaging ( MRI ) accuracy after neoadjuvant systemic therapy ( NST ) for breast cancer varies according to hormone receptor ( HR ), human epidermal growth factor receptor type‐2 ( HER2 ) subtype and Ki‐67 proliferation index. Whether MRI accuracy varies by genomic signatures is unknown. We examined the accuracy of MRI in the NEONAB trial ( Clinicaltrials.gov #: NCT01830244 ). Aim To examine the accuracy of MRI to predict pathological response to neoadjuvant therapy for breast cancer in the NEONAB trial. Methods Patients with stages II–III breast cancer received sequential epirubicin, cyclophosphamide and nab‐ paclitaxel and trastuzumab if they were HER2 +. Sensitivity, specificity, positive predictive value ( PPV ) and negative predictive value ( NPV ) were calculated to assess the utility of preoperative MRI to predict pathological complete response ( pCR ). Bland‐Altman plots were used to assess agreement between MRI and pathological assessment of residual disease. Results MRI correctly predicted pCR in 64.1% of the cohort. Sensitivity and specificity were 52% and 78%, respectively; PPV 73% and NPV 58%. MRI predicted pCR most accurately in HER2 ‐positive patients; sensitivity 58%, specificity 100%, PPV 100% and NPV 38%. MRI had higher PPV and NPV in tumours with Ki‐67 ≥ 15% than tumours with Ki‐67 < 15%, 75% versus 50% and 57.5% versus 50%, respectively. In this study, MRI underestimated residual tumour size by 1.65 mm (limits of agreement: 43.07–39.77 mm). Conclusions MRI appears more accurate for predicting pCR in HER2 + disease than other subtypes and in cancers with Ki‐67 ≥ 15% compared to those with Ki‐67 < 15%. Accuracy of MRI in our HR +, RS ≥ 25 cohort is comparable to previous reports of unselected HR + disease. MRI post‐ NST should be interpreted in conjunction with HER2 status and Ki‐67 index of the primary.