Predicting response to neoadjuvant chemotherapy with liquid biopsies and multiparametric MRI in patients with breast cancer

Accurate prediction of response to neoadjuvant chemotherapy (NAC) can help tailor treatment to individual patients' needs. Little is known about the combination of liquid biopsies and computer extracted features from multiparametric magnetic resonance imaging (MRI) for the prediction of NAC response in breast cancer. Here, we report on a prospective study with the aim to explore the predictive potential of this combination in adjunct to standard clinical and pathological information before, during and after NAC. The study was performed in four Dutch hospitals. Patients without metastases treated with NAC underwent 3 T multiparametric MRI scans before, during and after NAC. Liquid biopsies were obtained before every chemotherapy cycle and before surgery. Prediction models were developed using penalized linear regression to forecast residual cancer burden after NAC and evaluated for pathologic complete response (pCR) using leave-one-out-cross-validation (LOOCV). Sixty-one patients were included. Twenty-three patients (38%) achieved pCR. Most prediction models yielded the highest estimated LOOCV area under the curve (AUC) at the post-treatment timepoint. A clinical-only model including tumor grade, nodal status and receptor subtype yielded an estimated LOOCV AUC for pCR of 0.76, which increased to 0.82 by incorporating post-treatment radiological MRI assessment (i.e., the "clinical-radiological" model). The estimated LOOCV AUC was 0.84 after incorporation of computer-extracted MRI features, and 0.85 when liquid biopsy information was added instead of the radiological MRI assessment. Adding liquid biopsy information to the clinical-radiological resulted in an estimated LOOCV AUC of 0.86. In conclusion, inclusion of liquid biopsy-derived markers in clinical-radiological prediction models may have potential to improve prediction of pCR after NAC in breast cancer.

MRI to assess response after neoadjuvant chemotherapy in breast cancer subtypes: a systematic review and meta-analysis

This meta-analysis aimed to estimate and compare sensitivity, specificity, positive- (PPV) and negative predictive value (NPV) of magnetic resonance imaging (MRI) for predicting pathological complete remission (pCR) after neoadjuvant chemotherapy (NAC) in patients with early-stage breast cancer. We stratified for molecular subtype by immunohistochemistry (IHC) and explored the impact of other factors. Two researchers systematically searched PUBMED and EMBASE to select relevant studies and extract data. For meta-analysis of sensitivity and specificity, we used bivariate random-effects models. Twenty-six included studies contained 4497 patients. There was a significant impact of IHC subtype on post-NAC MRI accuracy (p = 0.0082) for pCR. The pooled sensitivity was 0.67 [95% CI 0.58-0.74] for the HR-/HER2-, 0.65 [95% CI 0.56-0.73] for the HR-/HER2+, 0.55 [95% CI 0.45-0.64] for the HR+/HER2- and 0.60 [95% CI 0.50-0.70] for the HR+/HER2+ subtype. The pooled specificity was 0.85 [95% CI 0.81-0.88] for the HR-/HER2-, 0.81 [95% CI 0.74-0.86] for the HR-/HER2+, 0.88[95% CI 0.84-0.91] for the HR+/HER2- and 0.74 [95% CI 0.63-0.83] for the HR+/HER2+ subtype. The PPV was highest in the HR-/HER2- subtype and lowest in the HR+/HER2- subtype. MRI field strength of 3.0 T was associated with a higher sensitivity compared to 1.5 T (p = 0.00063). The accuracy of MRI for predicting pCR depends on molecular subtype, which should be taken into account in clinical practice. Higher MRI field strength positively impacts accuracy. When intervention trials based on MRI response evaluation are designed, the impact of IHC subtype and field strength on MR accuracy should be considered.

Population-based estimates of overtreatment with adjuvant systemic therapy in early breast cancer patients with data from the Netherlands and the USA

Purpose

Although adjuvant systemic therapy (AST) helps increase breast cancer-specific survival (BCSS), there is a growing concern for overtreatment. By estimating the expected BCSS of AST using PREDICT, this study aims to quantify the number of patients treated with AST without benefit to provide estimates of overtreatment.

Methods

Data of all non-metastatic unilateral breast cancer patients diagnosed in 2015 were retrieved from cancer registries from The Netherlands and the USA. The PREDICT tool was used to estimate AST survival benefit. Overtreatment was defined as the proportion of patients that would have survived regardless of or died despite AST within 10 years. Three scenarios were evaluated: actual treatment, and recommendations by the Dutch or USA guidelines.

Results

59.5% of Dutch patients were treated with AST. 6.4% (interquartile interval [IQI] = 2.5, 8.2%) was expected to survive at least 10 years due to AST, leaving 93.6% (IQI = 91.8, 97.5%) without AST benefit (overtreatment). The lowest expected amount of overtreatment was in the targeted and chemotherapy subgroup, with 86.5% (IQI = 83.4, 89.6%) overtreatment, and highest in the only endocrine treatment subgroup, with 96.7% (IQI = 96.0, 98.1%) overtreatment. Similar results were obtained using data from the USA, and guideline recommendations.

Conclusion

Based on PREDICT, AST prevents 10-year breast cancer death in 6.4% of the patients treated with AST. Consequently, AST yields no survival benefit to many treated patients. Especially improved personalization of endocrine therapy is relevant, as this therapy is widely used and is associated with the highest amount of overtreatment.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10549-022-06550-2.

Preoperative indication for systemic therapy extended to patients with early-stage breast cancer using multiparametric 7-tesla breast MRI

Purpose

To establish a preoperative decision model for accurate indication of systemic therapy in early-stage breast cancer using multiparametric MRI at 7-tesla field strength.

Materials and methods

Patients eligible for breast-conserving therapy were consecutively included. Patients underwent conventional diagnostic workup and one preoperative multiparametric 7-tesla breast MRI. The postoperative (gold standard) indication for systemic therapy was established from resected tumor and lymph-node tissue, based on 10-year risk-estimates of breast cancer mortality and relapse using Adjuvant! Online. Preoperative indication was estimated using similar guidelines, but from conventional diagnostic workup. Agreement was established between preoperative and postoperative indication, and MRI-characteristics used to improve agreement. MRI-characteristics included phospomonoester/phosphodiester (PME/PDE) ratio on 31-phosphorus spectroscopy (³¹P-MRS), apparent diffusion coefficients on diffusion-weighted imaging, and tumor size on dynamic contrast-enhanced (DCE)-MRI. A decision model was built to estimate the postoperative indication from preoperatively available data.

Results

We included 46 women (age: 43-74yrs) with 48 invasive carcinomas. Postoperatively, 20 patients (43%) had positive, and 26 patients (57%) negative indication for systemic therapy. Using conventional workup, positive preoperative indication agreed excellently with positive postoperative indication (N = 8/8; 100%). Negative preoperative indication was correct in only 26/38 (68%) patients. However, ³¹P-MRS score (p = 0.030) and tumor size (p = 0.002) were associated with the postoperative indication. The decision model shows that negative indication is correct in 21/22 (96%) patients when exempting tumors larger than 2.0cm on DCE-MRI or with PME>PDE ratios at ³¹P-MRS.

Conclusions

Preoperatively, positive indication for systemic therapy is highly accurate. Negative indication is highly accurate (96%) for tumors sized ≤2,0cm on DCE-MRI and with PME≤PDE ratios on ³¹P-MRS.

Abstract P4-02-07: Association between computer-derived features of the ipsilateral breast on DCE-MRI and the 70-gene signature in patients with invasive breast cancer

Introduction

Molecular assays such as the 70-gene signature are increasingly used as prognostic indicators to select chemotherapy in individual patients. These assays are typically derived from postoperative excision specimens and require several weeks to complete. Earlier assessment of the results of such assays could open up new therapeutic options in subgroups of patients, potentially avoiding overtreatment of early breast cancer. Although molecular assays may be derived from biopsied tissue, tumor heterogeneity may cause uncertainty. Dynamic contrast-enhanced MRI (DCE-MRI) depicts some of the hallmarks of cancer that are tested by these molecular essays. The goal of this study was to investigate the association between the postoperatively derived 70-gene signature and computer-derived DCE-MRI features of the ipsilateral breast prior to surgery.

Material and Methods

Sixty-nine patients with node-negative invasive breast cancer were enrolled between 2003 and 2006. These patients received a preoperative MRI in study setting and a postoperative 70-gene signature assay. Association between preoperative features and the 70-gene signature was evaluated using a computer prediction model combining clinical features and automatically extracted MRI features. The clinical features were age at diagnosis and largest tumor diameter on MRI. The MRI features were rate of contrast uptake in the tumor, rate of wash-out, tumor volume, and two features from the intramammary blood vessel tree (total length and mean rate of contrast uptake). The features were transformed into an orthogonal feature set using principal component analysis. Association with the 70-gene signature (positive or negative indication for systemic therapy) was evaluated using binary logistic regression. Model performance was measured using the area under the receiver operating characteristics curve (AUC) after bootstrap validation using 200 iterations. Two operating points were examined: one to predict a positive 70-gene signature with high certainty (i.e., at high positive-predictive value (PPV)) and one to predict a negative signature with high certainty (i.e., at high negative-predictive value (PPV)).

Results

The average patient age at diagnosis was 48 years (range: 32-58). The median largest tumor diameter on MRI was 17 mm (range: 5-40). The 70-gene signature was positive in 29/69 (42%) patients. The computer prediction model achieved an AUC of 0.72 after bootstrap validation. At high PPV, 10/29 (34.5%) positive 70-gene signatures were identified preoperatively at the expense of 2/40 (5.0%) false-positive. The PPV was 10/12 (83.3%). At high NPV, 12/40 (30.0%) negative 70-gene signatures were identified at the expense of 1/29 (3.5%) false-negative signature. The NPV was 12/13 (92.3%).

Conclusion

Computer-derived DCE-MRI features from the ipsilateral breast in combination with clinical parameters show potential to preoperatively assess a negative outcome of the 70-gene signature in approximately one-third of the total patient group.

Citation Format: van der Velden BHM, Schmitz AMTh, Loo CE, Gilhuijs KGA. Association between computer-derived features of the ipsilateral breast on DCE-MRI and the 70-gene signature in patients with invasive breast cancer. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P4-02-07.

Dual-head gamma camera system for intraoperative localization of radioactive seeds

Breast-conserving surgery is a standard option for the treatment of patients with early-stage breast cancer. This form of surgery may result in incomplete excision of the tumor. Iodine-125 labeled titanium seeds are currently used in clinical practice to reduce the number of incomplete excisions. It seems likely that the number of incomplete excisions can be reduced even further if intraoperative information about the location of the radioactive seed is combined with preoperative information about the extent of the tumor. This can be combined if the location of the radioactive seed is established in a world coordinate system that can be linked to the (preoperative) image coordinate system. With this in mind, we propose a radioactive seed localization system which is composed of two static ceiling-suspended gamma camera heads and two parallel-hole collimators. Physical experiments and computer simulations which mimic realistic clinical situations were performed to estimate the localization accuracy (defined as trueness and precision) of the proposed system with respect to collimator-source distance (ranging between 50 cm and 100 cm) and imaging time (ranging between 1 s and 10 s). The goal of the study was to determine whether or not a trueness of 5 mm can be achieved if a collimator-source distance of 50 cm and imaging time of 5 s are used (these specifications were defined by a group of dedicated breast cancer surgeons). The results from the experiments indicate that the location of the radioactive seed can be established with an accuracy of 1.6 mm  ±  0.6 mm if a collimator-source distance of 50 cm and imaging time of 5 s are used (these experiments were performed with a 4.5 cm thick block phantom). Furthermore, the results from the simulations indicate that a trueness of 3.2 mm or less can be achieved if a collimator-source distance of 50 cm and imaging time of 5 s are used (this trueness was achieved for all 14 breast phantoms which were used in this study). Based on these results we conclude that the proposed system can be a valuable tool for (real-time) intraoperative breast cancer localization.

Association of primary tumour FDG uptake with clinical, histopathological and molecular characteristics in breast cancer patients scheduled for neoadjuvant chemotherapy

PURPOSE

The aim of this study was to evaluate the association of primary tumour (18)F-fluorodeoxyglucose (FDG) uptake with clinical, histopathological and molecular characteristics of breast cancer patients scheduled for neoadjuvant chemotherapy. Second, we wished to establish for which patients pretreatment positron emission tomography (PET)/CT could safely be omitted because of low FDG uptake.

METHODS

PET/CT was performed in 214 primary stage II or III breast cancer patients in the prone position with hanging breasts. Tumour FDG uptake was qualitatively evaluated to determine the possibility of response monitoring with PET/CT and was quantitatively assessed using maximum standardized uptake values (SUV(max)). FDG uptake was compared with age, TNM stage, histology, hormone and human epidermal growth factor receptor 2 status, grade, Ki-67 and molecular subtype in univariable and multivariable analyses.

RESULTS

In 203 tumours (95 %) FDG uptake was considered sufficient for response monitoring. No subgroup of patients with consistently low tumour FDG uptake could be identified. In a univariable analysis, SUV(max) was significantly higher in patients with distant metastases at staging examination, non-lobular carcinomas, tumours with negative hormone receptors, triple negative tumours, grade 3 tumours, and in tumours with a high proliferation index (Ki-67 expression). After multiple linear regression analysis, triple negative and grade 3 tumours were significantly associated with a higher SUV(max).

CONCLUSION

Primary tumour FDG uptake in breast cancer patients scheduled for neoadjuvant chemotherapy is significantly higher in tumours with prognostically unfavourable characteristics. Based on tumour characteristics associated with low tumour FDG uptake, this study was unable to identify a subgroup of patients unlikely to benefit from pretreatment PET/CT.

P5-10-02: Relevance of Magnetic Resonance Imaging To Predict Disease-Free Survival after Neoadjuvant Chemotherapy of Breast Cancer

Purpose: To explore the relevance of magnetic resonance imaging (MRI) to predict disease free survival (DFS) after neoadjuvant chemotherapy (NAC) of breast cancer.

Patients and Methods

Between July 2000 and December 2007, MRI examinations were performed in 188 women before, during and after NAC in the context of a single-institution review board approved study. Patients were consecutively included after informed consent. Interpretation of MRI was revised by an experienced breast MR radiologists and included assessment of lesion morphology, changes in morphology, size, and contrast uptake kinetics (initial and late enhancement).

MRI features and known prognostic markers of breast cancer (age, tumor response at pathology, tumor size at baseline, immunohistochemistry-derived breast cancer subtype (triple-negative; HER2−positive or ER-positive/HER2−negative)) were correlated with DFS. Multivariate Cox regression analysis was used with forward LR feature selection. Kaplan Meier curves were obtained to explore the impact of relevant associations.

Results: Follow-up data were available of 184 women. The median follow-up time was 57,6 months (range 32,4 — 125). In 30 women events were found (26 breast cancer related deaths; 29 distant metastasis and 12 local/regional recurrences).

At multivariate analysis, only breast cancer subtype (p=0.004) and largest diameter of late enhancement at MRI after NAC (p=0.006) retained prognostic value in favour of response at final pathology, age and tumor size at baseline. Cumulative survival at 60 months (kaplanmeier curves) was 70%, 86.7%, and 89.7% for triple-negatives, HER2−positive and ER-positive/HER2−negative subtypes [figure 1], respectively, and 88.5%, 81.4 % and 55.1% for absence of washout/plateau after NAC, between 0 and 30 mm washout/plateau, and ≥ 30 mm washout/plateau, respectively [figure 2].

Conclusions MRI after NAC in conjunction with breast cancer subtype has potential as complementary predictor for DFS. Larger diameters of residual late enhancement at MRI after NAC are associated with inferior DFS at 60 months.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P5-10-02.

P2-08-04: Computer-Derived Breast MRI Features Have Complementary Value for Preoperative Selection of Systemic Drug Therapy in Node-Negative Stage-I/II Breast Cancer Patients

Background: Typical guidelines for adjuvant systemic drug therapy require assessment of lymph node status, tumor extent and grade. Increasing interest exists, however, for preoperative therapy (neoadjuvant drug therapy and preoperative partial breast irradiation). Here, representative excision specimens are not available to assess eligibility for systemic therapy. Moreover, tumor grade may be difficult to assess in core biopsies resulting in underestimation rates up to 40%. Contrast-enhanced MRI has been shown to correlate with underlying tumor biology, but it is unknown whether it can complement eligibility criteria for systemic drug therapy.

Purpose: To assess the complementary value of MRI to determine eligibility for systemic drug therapy prior to breast-conserving surgery in node-negative stage-I/II breast cancer patients.

Materials and methods: Patients with preoperative node-negative invasive breast cancer ≥1.0 cm and eligible for breast-conserving therapy after conventional breast imaging and MRI were consecutively included between February 2000 and March 2007. Informed consent was obtained from all patients. Eligibility to systemic therapy was determined on the basis of national guidelines using age, size, tumor grade, as well as axillary lymph node status at final pathology. Twenty temporal and morphological features of contrast uptake at MRI were automatically analyzed by a previously build CAD workstation1,2. Preoperative lymph node status was derived from ultrasound-guided fine-needle aspiration. Multivariate logistic regression and receiver-operating characteristics (ROC) analysis was used to assess associations between preoperative features (age, ER status, computer-extracted MRI features) and eligibility to systemic therapy based on post-operative features (tumor size, grade, lymph node status).

Results: Three-hundred-and-eighty-six patients were included. The mean patient age was 58 years. The mean tumor size at pathology was 1.6 cm. Tumor grade was I, II and III in 128 (33%), 163 (42%), and 94 (24%) of tumors, respectively. Post-operative lymph node status was positive in 115/386 (30%) patients. In total, 262/386 (68%) patients were eligible for systemic drug therapy based on post-operative pathology. Multivariate analysis of preoperatively available features yielded ER status, and principle components 1, 6, 8 and 15 of the computer-extracted features. These components describe tumor volume and shape, heterogeneity of contrast uptake, late-enhancement kinetics, and probability of malignancy. The resulting model correlated with the Adjuvant! program (R=0.55, p<0.0001). The area under the ROC curve was 0.82 (p<0.0001). Without the model, agreement between preoperative and postoperative assessment of eligibility to drug therapy was 232/386 (60%) at 15/124 (12%) overestimation rate. With the MRI model, it increased to 258/386 (67%) (p=0.004) without increasing overestimation rate.

Conclusion: Computer-analysis of contrast-enhanced MRI has potential to complement preoperative selection of stage I/II node-negative breast-cancer patients for systemic drug therapy.

Ref:

1. Gilhuijs et al., Radiology 2002; 225: 907–916

2. Deurloo et al., Radiology 2005; 234: 693–701

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P2-08-04.

Excised and irradiated volumes in relation to the tumor size in breast-conserving therapy

In early-stage breast cancer and DCIS patients, breast-conserving therapy is today's standard of care. The purpose of this study was to evaluate the relation between the microscopic tumor diameter (mTD), the excised specimen (ES) volume, and the irradiated postoperative complex (POC) volume, in patients treated with breast-conserving therapy. In 186 patients with pTis-2N0 breast cancer, the mTDs, ES, and POC volumes (as delineated on the radiotherapy-planning CT scan), were retrospectively determined. Linear regression analysis was performed to study the association between the mTD, and the ES and POC volumes. The explained variance (r (2)) was calculated to establish the proportion of variation in the outcome variable that could be explained by the determinant (P ≤ 0.05). Moreover, the influence of tumor characteristics, age, surgical procedures, and breast size was studied. Median mTD was 1.2 cm (range 0.1-3.6 cm), median ES volume was 60 cm(3) (range 6-230 cm(3)) and median POC volume was 15 cm(3) (range 0.5-374 cm(3)). The POC was not clearly visible on the majority of the CT scans, based on a median assigned cavity visualization score of 3 (range 1-5). The explained variance for the mTD on the ES volume was low (r(2) = 0.08, P < 0.001). A slightly stronger association was observed in palpable tumors (r(2) = 0.23, P < 0.001) and invasive lobular carcinomas (r(2) = 0.39, P = 0.01). Furthermore, weak associations were observed between POC volume and mTD (r(2) = 0.04, P = 0.01), and POC and ES volume (r(2) = 0.23, P < 0.001). A weak association was observed between breast volume and ES volume (r(2) = 0.27, P < 0.001). In conclusion, both the excised and the irradiated POC volumes did not show a clinically relevant association with the mTD in women with early-stage breast cancer treated with breast-conserving therapy. Future studies should focus on improvement of surgical localization, development of image-guided, minimally invasive operation techniques, and more accurate image-guided target volume delineation in radiotherapy.

The impact of preoperative breast MRI on the re-excision rate in invasive lobular carcinoma of the breast

Re-excision rates after breast conserving surgery(BCS) of invasive lobular carcinoma (ILC) are high.Preoperative breast MRI has the potential to reduce re-excision rates, but may lead to an increased rate of mastectomies. Hence, we assessed the influence of preoperative breast MRI on the re-excision rate and the rate of mastectomies. We performed a retrospective cohort study of a consecutive series of patients with ILC who presented in one of two dedicated tertiary cancer centers between 1993 and 2005. We assessed the initial type of surgery(BCS or mastectomy), the re-excision rate and the final type of surgery. Patients were stratified into two groups:those who received preoperative MRI (MR? group) and those who did not (MR- group). In the MR- group, 27%of the patients underwent a re-excision after initial BCS. In the MR? group, this rate was significantly lower at 9%.The odds ratio was 3.64 (95% CI: 1.30-10.20, P = 0.010).There was a trend towards a lower final mastectomy rate in the MR? group compared to the MR- group (48 vs. 59%,P = 0.098). In conclusion, preoperative MRI in patients with ILC can reduce re-excision rates without increasing the rate of mastectomies.

Reduction in the number of sentinel lymph node procedures by preoperative ultrasonography of the axilla in breast cancer

Currently, breast cancer patients without clinically suspicious lymph nodes are candidates for sentinel lymph node procedures (SLNPs). The aims of this study were to investigate whether preoperative axillary ultrasonography and fine-needle aspiration cytology (FNA) can reduce the number of the more time-consuming SLNPs, and to identify a subset of quantitative nodal features to predict metastatic involvement. 268 axillae were ultrasonographically examined. FNA was performed on suspicious nodes (smallest diameter > or =5 mm or atypical cortex appearance). SLNP was omitted if a tumour-positive node was found on FNA. Length, width, maximum cortex thickness and appearance of cortex and hilus were ultrasonographically established. In 93 axillae (35%), at least one node was detected with ultrasound. FNA was performed once per axilla on 66 nodes; 37 (56%) contained tumour cells. 31% of all tumour-positive axillae (macro-+micrometastases) was found by ultrasound and FNA (37/121). 41% of all axillae containing macrometastases was found by ultrasound and FNA (36/87). SLNPs were reduced by 14% (37/268). Maximum cortex thickness is the main feature to predict metastatic involvement (area under Receiver Operating Characteristic (ROC) curve (A(Z))=0.87).