USEFULNESS OF PREOPERATIVE BREAST MAGNETIC RESONANCE IMAGING (MRI) IN PRESURGICAL STAGING OF BREAST CANCER M. Ave-Seijas M. Arias A. Iglesias B. Nieto A. Tilve C. García-Durán HospitalXeral-CíesVigo/ES

INTRODUCTION Breast cancer is the most frequent malignant tumor in women Nowadays breast tumor treatment is reaching a more conservative approach This new situation urges us to develop new diagnostic techniques to obtain an accurate local staging A better presurgical local staging of these patients is allowed with MRI

MAIN PURPOSE To assess the influence of preoperative bilateral breast magnetic resonance imaging (MRI) in surgical management of patients with infiltrative breast cancer susceptible of conservative surgery, comparing the sensibility, specificity and positive and negative predictive values for lesion detection in breast MRI, mammography and ultrasonography (US) 3

SECONDARY PURPOSES To check the validity of MRI as a breast size tumor predictor in invasive breast carcinomas To determine the role of breast MRI in the detection of multifocality/multicentricity and contralateral breast cancer To evaluate mammography, ultrasound and breast MRI sensitivity, specificity and predictive values in the determination of multifocality and multicentricity in breast tumors To identify causes that may influence false positive and false negative results in breast MRI studies for local staging

METHODS AND MATERIALS TYPE OF STUDY: Descriptive retrospective RM EQUIPMENT 1.5-T magnet (Signa Horizont, General Electric, Milwakee USA) Dedicated phased-array breast-MR coil

METHODS AND MATERIALS IMAGING PROTOCOL : Bilateral study with fat suppression Temporal resolution <1 min and spatial resolution 2.5mm Power injector and gadolinium contrast (0.15 mmol / kg) Axial STIR and T2-weighted MR images Dynamic axial 3D T1-weighted fat suppressed spoiled gradient-echo images before and after injection of gadolinium (multiple runs over 5-8 minutes, each run <2 min for kinetics) Sagittal T1-weighted fat suppressed images before and after administration of gadolinium Kuhl; Radiology August 2007

Dynamic 3D GRE T1 Axial STIR Axial SE T1 Sagittal SE T1 fat-sat with fat saturation after injection of 0.15 mmol / kg of gadolinium

METHOD AND MATERIALS PATIENTS Eighty patients with core needle biopsy diagnosis of infiltrative breast cancer studied between June 2007 and May 2008, susceptible of conservative surgical treatment after clinical examination, mammography and US, sent for preoperative contrast-enhanced MRI imaging “Second look” US and us-guided biopsy were made in suspicious lesions only detected with RM that involved a change in surgical treatment VARIABLES Tumor median size and multifocality, multicentricity or contralateral disease were assessed and correlated with histopathology findings 8

Average difference (p) RESULTS AGE: 58,88 ±13,05 years. HISTOLOGIC TYPE: Infiltrating Ductal 77 (91,25%) Lobular 7 (8,75%) TUMOR MEDIAN SIZE   Ductal Lobular Total Average difference (p) Histopathology 1,97 ± 0,76 2,70 ± 0,75 2,04 ± 0,78 Mammography 1,56±1,12 0,450 ±1,04 (p< 0.05) US 1,66 ± 0,67 1,87 ± 0,76 1,68 ± 0,68 0,036 ± 0,85 MRI 1,87±0,76 3,18 ± 1,01 1,98 ± 0,79 -0,63 ± 0,49 (p>0.05)

Results Multicentricity, multifocality Single Multifocal Multicentric Histopatology 56 (70,0%) 14 (17,5%) 10 (2,5%) Mammograhy 77 (86,3%) 3 (3,8%) 0 (0%) US 69 (86,2%) 9(11,25) 2(2,5) MRI 13 (16,2%) 11 (13,7%) THERE WERE NOT CONTRALATERAL BREAST PATHOLOGICAL FINDINGS IN THIS STUDY   Sensibility Specifity PPV NPV Mammography 14% 100% 75% US 42% 98% 91% 79% MRI 92% 96%

RESULTS MRI detected additional suspicious previously unsuspected lesions in 11 patients (21%) MRI detected multifocality undetected on mamography/US in 8 patients (10%): Surgical management was changed into a LARGER LUMPECTOMY C A B FIGURE 1: There is a single mass in mammography (A) and US (B), resulting in multifocal lesions in MRI (C).

RESULTS MRI detected multicentricity undetected on mamography/US in 9 patients (11%): Surgical management was changed into MASTECTOMY C A Figure 2: Mammogram (A) and US (B) detected a single mass which was multicentric on MRI (C). B

RESULTS MRI detected additional suspicious previously unsuspected lesions in 11 patients (21%). They all were confirmed as malignant MRI showed a higher sensitivity (92%) and negative predictive value (96%) to detect multifocal and multicentric tumor when compared to mammography (sensibility 14% and negative predictive value 75%) and US (sensibility 42% and negative predictive value 79%)

RESULTS False positives in MRI (n =2) False negatives in MRI (n=2) Complex sclerosing adenosis: Initial lumpectomy was extended Mastopathic focus: Treatment was not changed False negatives in MRI (n=2) Small foci of lobular carcinoma: Treatment did not need any change Small foci of Infiltrating carcinoma: Treatment was converted into a mastectomy

RESULTS B A C Figure 3: False positive MRI (A, B): A small focus of complex sclerosing adenosis (0,4mm) located 2 cm away from the main nodule (C) histopathology B A Figure 4: False positive MRI (A, B). Close to the main lesion MRI depicted some small enhancing nodules, that finally corresponded to pathologically proven mastopatic areas.

RESULTS B A Figure 5: False negative: (A) MRI depicted the main lesion that corresponded to lobular carcinoma, but (B) failed to show a small peripheral lobular carcinoma focus in the same quadrant B A Figure 6: False negative: (A) MRI showed the infiltrating tumor with small areas of intraductal carcinoma extension. (B) Histopathology proved extensive intraductal extension. Management changed from quadrantectomy to mastectomy

DISCUSSION   European Guidelines: 80% breast tumors are subsidiary of conservative surgery and radiotherapy Accurate local staging PREVENTS RECURRENCY DECREASES REOPERATION   THE MOST SENSITIVE PREOPERATIVE DIAGNOSTIC TECNIQUE IS MRI Tumor size “Unseen” focus in the same breast: 6-27% “Hidden” contralateral breast tumor: 3-9% Intraductal extension Cleavage plane with the chest wall Schell et al. AJR May 2009

DISCUSSION MRI influences patient management (15-27%) Larger local surgery (5-9%) Mastectomy (9-17%) Schell et al AJR Mayo 2009 Kuhl Radiology September 2007 Bedrosian et al Cancer August 2003 NOWADAYS DISCUSSION False positives? Overtreatment? Cost-benefit? Comstock et al RSNA 2007

MAIN CONCLUSION 1- Breast MRI depicts additional tumoral foci unsuspected with other techniques, so it improves the surgical management . Breast MRI showed a higher sensitibility and negative predictive value when compared to mammography and breast US

CONCLUSION 2- Breast MR imaging is the best preoperative technique to make a local staging in breast tumors 3- Breast MRI is superior to ultrasound and mammography to depict multifocality / multicentricity 4- Breast MRI is a technique with high sensitivity, specificity,PPV and NPV in the diagnosis of multicentricity / multifocality in invasive breast cancer 5- To minimize the number of false positives and negatives in breast MRI it is essential to use a proper technique

CONCLUSION 6- Preoperative breast MRI should not lead to a delay in surgical planning but to a better planning 7- Preoperative breast MRI should permit a more appropriate therapeutic management and reduce the rate of reoperation 8- There should be a careful management and individualized treatment decisions in patients with lesions detected only with MRI in order to avoid overtreatment

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