Is subareolar intraoperative biopsy still necessary to predict nipple involvement?

OBJECTIVE

To predict the occult tumor involvement of nipple-areola complex (NAC) using preoperative MR imaging and to investigate whether the intraoperative histopathological examination of the subareolar tissue is still necessary.

PATIENTS AND METHODS

Out of 712 patients submitted to nipple-sparing mastectomy (NSM) between 2014 and 2019, we selected 188 patients who underwent preoperative breast MRI. Breast MRI and intraoperative histopathological examination of the subareolar tissue were performed to predict NAC involvement at permanent pathology. All parameters were correlated with final pathological NAC assessment by univariate and multivariate analysis.

RESULTS

Forty-three patients (22.9%) had tumor involvement of the NAC. At univariate analysis, non-mass enhancement type (p = 0.009), multifocality/multicentricity (p = 0.002), median tumor size (p < 0.001), median tumor-NAC distance measured by MRI (p < 0.001), tumor-NAC distance ≤ 10 mm (p < 0.001) and tumor-NAC distance ≤ 20 mm (p < 0.001), and lymphovascular invasion (p = 0.001) were significantly correlated with NAC involvement. At multivariate analysis, only tumor-NAC distance ≤ 10 mm retained statistical significance. The sensitivity and specificity of MRI tumor-NAC distance ≤ 10 mm were 79.1% and 97.2% and those of intraoperative pathologic assessment were 74,4% and 100%, respectively.

CONCLUSIONS

Tumor-NAC distance is the only reliable MRI characteristic that can predict NAC involvement in breast cancer patients. Although several cut-offs showed promising performances, intraoperative pathologic assessment is still mandatory.

Association between background parenchymal enhancement and tumor response in patients with breast cancer receiving neoadjuvant chemotherapy

PURPOSE

To analyze the relationships between background parenchymal enhancement (BPE) of the contralateral healthy breast and tumor response after neoadjuvant chemotherapy (NAC) in women with breast cancer.

MATERIALS AND METHODS

A total of 228 women (mean age, 47.6 years±10 [SD]; range: 24-74 years) with invasive breast cancer who underwent NAC were included. All patients underwent breast magnetic resonance imaging (MRI) before and after NAC and 127 patients underwent MRI before, during (after the 4th cycle of NAC) and after NAC. Quantitative semi-automated analysis of BPE of the contralateral healthy breast was performed. Enhancement level on baseline MRI (baseline BPE) and MRI after chemotherapy (final BPE), change in enhancement rate between baseline MRI and final MRI (total BPE change) and between baseline MRI and midline MRI (early BPE change) were recorded. Associations between BPE and tumor response, menopausal status, tumor phenotype, NAC type and tumor stage at diagnosis were searched for. Pathologic complete response (pCR) was defined as the absence of residual invasive cancer cells in the breast and ipsilateral lymph nodes.

RESULTS

No differences were found in baseline BPE, final BPE, early and total BPE changes between pCR and non-pCR groups. Early BPE change was higher in non-pCR group in patients with stages 3 and 4 breast cancers (P=0.019) and in human epidermal growth factor receptor 2 (HER2)-negative patients (P=0.020).

CONCLUSION

Early reduction of BPE in the contralateral breast during NAC may be an early predictor of loss of tumor response, showing potential as an imaging biomarker of treatment response, especially in women with stages 3 or 4 breast cancers and in HER2 - negative breast cancers.

Role of DWI assessing nodal involvement and response to neoadjuvant chemotherapy in advanced breast cancer

OBJECTIVE

To explore the role of diffusion-weighted imaging (DWI) in the staging of axillary lymph nodes and the restaging after neoadjuvant chemotherapy (NAD) in advanced breast cancer.

PATIENTS AND METHODS

MRI examinations of forty-two patients diagnosed with advanced breast cancer addressed to NAD and axillary lymph node dissection (ALND) were reviewed. Apparent diffusion coefficients (ADC) of each visible node in DWI in the pathologic axilla (PA) and healthy axilla (HA) were measured at the time of diagnosis (t0) and after chemotherapy (t1); mean values of the ADC were calculated. Patients were classified as responders (R), non-responders (NR), macrometastasis (MA), micrometastasis (Mi).

RESULTS

Mean ADC was 0.92 ± 0.07 x 10-3 mm2/sec at t0 and 0.97 ± 0.06 x 10-3 mm2/sec at t1 (p = 0.284) in PA, 0.89 ± 0.06 x 10-3 mm2/sec at t0 and 0.92 ± 0.06 x 10-3 mm2/sec at t1 (p = 0.403) in HA, 0.95 ± 0.111 x 10-3 mm2/sec at t0 and 0.95 ± 0.14 x 10-3 mm2/sec at t1 (p = 0.954) in R group, 0.90 ± 0.09 x 10-3 mm2/sec at t0 and 0.97 ± 0.07 x 10-3 mm2/sec at t1 (p = 0.085) in NR group, 0.86 ± 0.10 x 10-3 mm2/sec at t0 and 0.99 ± 0.09 x 10-3 mm2/sec at t1 (p = 0.055) in MA, and 0.99 ± 0.23 x 10-3 mm2/sec at t0 and 0.95 ± 0.15 x 10-3 mm2/sec at t1 in Mi (p = 0.667).

CONCLUSIONS

Mean ADC between PA and HA, R and NR, MA and Mi did not significantly differ at t0 and t1 (p > 0.05). Variation in mean ADC between t0 and t1 was not significant in all groups (p > 0.05), except for a trend toward significance (p = 0.055) in MA. DWI has a potential role in restaging of macrometastatic axillary nodes after NAD.

Unenhanced breast magnetic resonance imaging: detection of breast cancer

OBJECTIVE

To evaluate the diagnostic performance of unenhanced MRI (UE-MRI) for malignant breast lesions and its reproducibility.

PATIENTS AND METHODS

We retrospectively included 118 patients who had breast MRI. DWI and STIR images were read in combination and referred to as UE-MRI; the presence or absence of the malignant lesion was noted by two observers. Their results were compared with those of final histopathology or with a two-year negative follow-up for diagnostic performance assessment; ROC curves were built. Diagnostic performance was stratified according to lesion site and size. Interobserver agreement was evaluated through the Cohen's k statistic.

RESULTS

Specificity of STIR and DWI was 99.3% and 95.7% for Reader 1; 99.3% and 96.4% for Reader 2. Sensitivity was 76.5% and 76.5% for Reader 1; 77.5% and 77.6% for Reader 2. The ROC AUC (Reader 1) was 0.869 and 0.844 for STIR and DWI, respectively (p<0.001 both); for Reader 2, values were 0.874 and 0.853 respectively (p<0.001 both). Lesion dimension ≤10 mm was associated with lower AUC values. Lesion site didn't influence the diagnostic performance. Interobserver agreement was very good for STIR and DWI (k=0.887, p <0.001, and k=0.867, p <0.001).

DISCUSSION

UE-MRI has a good overall diagnostic performance in the detection of breast cancer and a very good specificity for both STIR and DWI sequences. We observed reduced diagnostic performance for lesions ≤10 mm in size. Lesion's site isn't associated with a significantly decreased diagnostic performance of UE-MRI. There's a good interobserver agreement for both sequences (STIR and DWI).

CONCLUSIONS

UE-MRI may be employed in patients with contraindication to gadolinium. It has considerable specificity and positive predictive value and good reproducibility.

MRI evaluation of neoadjuvant low-dose fractionated radiotherapy with concurrent chemotherapy in patients with locally advanced breast cancer

OBJECTIVES

We address the diagnostic performance of breast MRI and the efficacy of neoadjuvant radiochemotherapy (NRC) treatment (NRC protocol) vs conventional neoadjuvant chemotherapy (NAC) in patients with locally advanced breast cancer.

METHODS

The NRC protocol consists of six anthracycline/taxane cycles and concomitant low-dose radiotherapy on breast tumour volume. Breast MRI was performed at baseline and after the last therapy cycle in 18 and 36 patients undergoing the NRC protocol or conventional NAC (propensity matching).

RESULTS

In both groups, we observed reduced tumour dimensions after the last cycle (p<0.001), and the response evaluation criteria in solid tumours (RECIST) class directly correlated with the tumour regression grade class after the last cycle (p<0.001). Patients in the NRC group displayed a higher frequency of complete/partial response than those in the NAC group (p=0.034). 17 out of 18 patients in the NRC group met the criteria for avoiding mastectomy based on final MRI evaluation. The RECIST classification displayed a superior diagnostic performance in the prediction of the response to treatment [area under the receiver operating characteristic curve (AUC)=0.72] than time-to-intensity curves and apparent diffusion coefficient (AUC 0.63 and 0.61). The association of the three above criteria yielded a better diagnostic performance, both in the general population (AUC=0.79) and in the NRC and the NAC group separately (AUC=0.82 and AUC=0.76).

CONCLUSIONS

The pathological response is predicted by MRI performed after the last cycle, if both conventional MRI and diffusion imaging are integrated. The NRC treatment yields oncological results superior to NAC. Advances in knowledge MRI could be used to establish the neoadjuvant protocol in breast cancer patients.

Extra-mammary findings in breast MRI

OBJECTIVES

Incidental extra-mammary findings in breast Magnetic Resonance Imaging (MRI) may be benign in nature, but may also represent a metastasis or another important lesion. We aimed to analyse the prevalence and clinical relevance of these unexpected findings.

METHODS

A retrospective review of 1535 breast MRIs was conducted. Only axial sequences were reassessed. Confirmation examinations were obtained in all cases.

RESULTS

285 patients had a confirmed incidental finding, which were located in the liver (51.9%), lung (11.2%), bone (7%), mediastinal lymph nodes (4.2%) or consisted of pleural/pericardial effusion (15.4%). 20.4% of incidental findings were confirmed to be malignant. Positive predictive value for MRI to detect a metastatic lesion was high if located within the bone (89%), lymph nodes (83%) and lung (59%), while it was low if located within the liver (9%) or if it consisted of pleural/pericardial effusion (6%). The axial enhanced sequence showed superior sensitivity to unenhanced images in detecting metastatic lesions, especially if only smaller (≤10 mm.) lesions were considered.

CONCLUSIONS

The prevalence of metastatic incidental extra-mammary findings is not negligible. Particular attention should be to incidental findings located within the lung, bone and mediastinal lymph nodes.

Diffusion-weighted imaging in breast cancer: relationship between apparent diffusion coefficient and tumour aggressiveness

AIM

To assess the utility of diffusion-weighted imaging in diagnosing and characterizing breast malignancy.

MATERIALS AND METHODS

From April 2006 to April 2009, all consecutive patients with breast cancer undergoing breast magnetic resonance imaging (MRI) and subsequent surgery in our hospital were enrolled in this study. MRI was performed using a 1.5 T MRI unit using a dedicated, bilateral, four-channel breast coil. The MRI protocol included a diffusion sequence acquired using b values of 0 and 1000 s/mm(2). For each malignant lesion the relationships between tumour grade and histology and the relative value of the apparent diffusion coefficient (ADC) were analysed.

RESULTS

There were 136 female patients with 162 lesions. Histology revealed 149 invasive carcinomas and 13 ductal carcinomas in situ. There were 34 grade 1, 61 grade 2, and 67 grade 3 lesions. The mean ADC value of all malignant lesions was 1.03×10(-3) mm(2)/s. The mean ADC values for invasive and in situ carcinomas were 1.03×10(-3) mm(2)/s and 1.05×10(-3) mm(2)/s, respectively. The mean ADC values for grade 1, 2, and 3 tumours were 1.25×10(-3) mm(2)/s, 1.02×10(-3) mm(2)/s, and 0.92×10(-3) mm(2)/s, respectively. A statistically significant (p<0.001) inverse correlation was disclosed between the ADC value and the tumour grading. The mean ADC value of the "less aggressive" group of disease (G1 and in situ lesions) was 1.19×10(-3) mm(2)/s, whereas the mean ADC value of the "more aggressive" group (G2-G3 invasive carcinomas) was 0.96×10(-3) mm(2)/s (p<0.001).

CONCLUSION

The study confirms the usefulness of diffusion imaging in assessing the aggressiveness of breast tumours. ADC appears to be a promising parameter in the evaluation of the degree of malignancy of breast cancer tissue.

Diffusion-weighted imaging in breast lesion evaluation

PURPOSE

The purpose of this study was to investigate the ability of diffusion-weighted imaging (DWI) and the apparent diffusion coefficient (ADC) in the detection and characterisation of breast lesions.

MATERIALS AND METHODS

From September 2005 to September 2007, 86 patients with breast lesions who underwent magnetic resonance imaging (MRI) in our department were included in our study. MRI was performed with a 1.5-T unit using a standard protocol including DWI sequence. For each breast lesion, the ADC value was calculated and compared with that of normal breast tissue and to the definitive pathological diagnosis. Mann-Whitney U and Kruskal-Wallis tests were used for statistical analysis.

RESULTS

A total of 126 breast lesions were detected. Pathology results revealed 100 malignant and 26 benign lesions. Mean diameter of lesions was 26.02 mm (range 4-90 mm), including 52 lesions <or=15 mm in size. Mean ADC value of normal glandular tissue was 1.55x10(-3) mm(2)/s. Mean ADC value of malignant lesions was 0.97x10(-3) mm(2)/s. Mean ADC value for benign lesions was 1.66x10(-3) mm(2)/s. Benign lesions showed ADC values significantly higher than malignant lesions (p<0.0001).

CONCLUSIONS

DWI provides reliable information to support MRI diagnosis of breast masses. ADC value appears a promising adjunctive parameter in distinguishing malignant from benign breast lesions.