A pilot study of a comprehensive financial navigation program in cancer survivors

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Background: Although financial toxicity is associated with poorer clinical outcomes in cancer survivors, few studies have attempted to address this toxicity. We developed a financial navigation program in collaboration with our partners (Consumer Education and Training Services (CENTS) and Patient Advocate Foundation (PAF)) to improve patients’ knowledge about cancer treatment costs, provide financial counseling, and help with out-of-pocket expenses. We conducted a pilot study to assess feasibility and early impact of this program. Methods: Patients (pts) within 1 year of a solid tumor diagnosis and 6 months of chemotherapy and/or radiation were recruited at the Seattle Cancer Care Alliance. Pts received a financial education course followed by monthly contact with a CENTS financial counselor and PAF case manager for 6 months. We measured program adherence, self-reported financial burden, anxiety about costs, program satisfaction, and type and amount of assistance provided. Results: We consented 34 pts (median age 60.5), the majority of whom were white (85%) and commercially insured (50%). Participants (n = 20) and non-participants (n = 14 who withdrew or were lost to follow up early on) did not differ in age, race, gender, education, income, or insurance type. Debt, income declines, and loans were reported by 55%, 55%, and 30% of pts. High financial burden and anxiety about costs (4 or 5; Likert scale) were reported by 37% and 47% of pts. High satisfaction with the education course, CENTS counselors, and PAF case managers were reported by 73%, 80%, and 91% of pts. CENTS counselors assisted pts most often with budgeting, retirement planning, and medical bill questions. PAF case managers assisted pts with gaps in insurance, debt or cost of living issues, and employment rights and disability applications. A total of $7,667 ($1,267 for pts and $6,400 for institutions) was obtained through charitable entities. Conclusions: Our findings confirm that a financial navigation program is feasible to implement, associated with high satisfaction, and provides concrete assistance to pts in navigating the cost of cancer care. Future work will focus on improving program adherence and measuring its impact on financial and clinical outcomes.

The use of 18F-fluoroestradiol (FES) and 18F-fluorodeoxyglucose (FDG) PET in the evaluation of breast cancer heterogeneity

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Background: 18F-Fluoroestradiol (FES) is an estrogen analogue that has been shown to be a promising biomarker in ER imaging of breast cancer. FES uptake correlates to ER expression, provides qualitative and quantitative assessment of multiple tumor sites simultaneously, and can predict response to endocrine therapies. Tumor heterogeneity is a known feature of metastatic breast cancer. Our work and others has shown that patients that have tumors with high FDG-PET SUV and low FES-PET SUV uptake have a poorer prognosis. Biopsies of metastatic disease may be done initially for diagnosis of metastatic disease, but are generally only performed in the setting of target identification for clinical trials. A change in ER or HER2 expression, however, can result in a change in therapy. FES-PET imaging offers a virtual biopsy and can reveal heterogeneity of the entire tumor burden. Methods: We reviewed our prior evaluations of tumor heterogeneity with FES-PET from 3 different studies. 46 breast cancer patients with metastatic disease (de novo or recurrent) who had biopsy proven ER+ primary breast cancer underwent FES-PET and FDG-PET imaging and a biopsy of a metastatic lesion prior to therapy initiation. ER and HER-2 expression was reviewed. Results: Of the 46 patients, 5 (11%) had ER- metastatic biopsies. One (2%) biopsy changed from ER+/HER-2 neg to ER-/HER-2+, and one (2%) biopsy changed from ER+/HER-2+ to ER+/HER-2-. All 5 patients (11%) with changes in ER/HER2 expression underwent a change in therapy due to the unexpected findings by metastatic biopsy. FDG findings helped to guide selection of biopsy sites. FES quantitative measures correlated with biopsy findings. Conclusions: Biopsy resulted in a change in therapy for > 10 % of patients enrolled in trials of FES imaging. Imaging can help identify heterogeneous tumor locations to assist identification of evolving tumor targets in breast cancer. In addition, FES imaging may reveal a change in tumor phenotype that can ultimately affect choice of therapy. Research Support: P01CA42045, R01CA72064

Impact of DNA repair deficiency signature on outcomes in triple negative breast cancer (TNBC) patients treated with AC chemotherapy (SWOG S9313)

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Background: Biomarkers of response and resistance to adjuvant chemotherapy for TNBC are needed. Deficiency in DNA damage response (DDR) and repair pathways have been reported in TNBC and may impact response to chemotherapy. Aims: To investigate DNA damage response deficiency (DDRD) molecular signature, BRCA1mRNA expression and Tumor Infiltrating Lymphocytes (TILs) as prognostic markers in TNBC patients treated with adjuvant AC on S9313. Methods: S9313 accrued 3125 early stage BC patients to two alternative schedules of AC with no difference in outcomes between the two arms. We identified 425 (14%) patients with centrally determined TNBC with tissue availability. DDRD signature (44 gene signature, Almac Inc.) and BRCA1expression (NanoString nCounter) were performed on RNA isolated from pre-treatment FFPE tumor tissue. DDRD score was classified in quartiles. TILs evaluation was performed using previously described criteria. Markers were tested for prognostic effect on DFS and OS using Cox regression model with adjustment for randomized treatment assignment. Results: For 425 TNBC patients median age: 45 yrs, and 5 year DFS and OS = 74% and 82%, respectively. DDRD signature was successfully evaluated in 89.6% (381/425) but only 267 (62.8%) met 60% tumor content criterion for inclusion. DDRD score quartiles were associated with DFS (5 year DFS 59% & 82% in the lowest & highest quartiles respectively, p = 0.0005) and OS (5 year OS 74% and 86% in lowest and highest quartiles respectively, p = 0.008). BRCA1 expression and TILs were successfully determined in 78% and 99% samples, respectively. BRCA1expression was not associated with DFS. TILs were associated with DFS (10% increase HR = 0.88; 95% CI 0.79-0.97; p = 0.016) and OS (HR = 0.84; 95% CI 0.74-0.94; p = 0.0005). DDRD score and TILs were highly correlated (Pearson = 0.62). In multivariate model of DFS including TILs and DDRD quartiles, only DDRD remains significant (p = 0.018). Conclusions: DDRD signature was prognostic in TNBC patients treated with AC chemotherapy and has the potential to be used as a selection criterion to identify TNBC patients whose prognosis is sufficiently poor to justify evaluation of alternative treatment.

Abstract P4-22-11: Combined targeted therapies for advanced triple negative breast cancer: A phase II trial of nab-paclitaxel and bevacizumab followed by maintenance targeted therapy with bevacizumab and erlotinib

Background: Chemotherapy remains the mainstay of therapy for patients with metastatic triple negative breast cancer (TNBC). We hypothesized that the addition of biologic agents targeting key pathways (bevacizumab targeting angiogenesis and erlotinib directed against EGFR) may prolong progression free survival (PFS) and offer a novel treatment strategy free from chemotherapy for patients with metastatic TNBC.

Methods: Patients with TNBC receiving initial therapy for metastatic disease were eligible for this multicenter phase II trial (NCT00733408) conducted at an academic center and affiliated, community practice sites. Induction therapy included nab-paclitaxel 100 mg/m2 IV Qweek (wk) and Bevacizumab 10 mg/kg IV Q2wks x 24 weeks. Patients free of progression at 24 wks began maintenance therapy with bevacizumab 10 mg/kg IV Q2wks and erlotinib 150 mg po daily until progression with radiographic assessment every 8 wks. Primary objective was PFS with secondary objectives of response rate, overall survival (OS) and safety. All eligible patients were included in the analysis of PFS and OS. Response was evaluated among patients with measurable disease by RECIST 1.1 with central review. Patients with inadequate disease assessments were coded as non-responders. Kaplan-Meier method was used to estimate PFS and OS with patients censored at date of last tumor assessment (PFS) or date of last follow up (OS).

Results: From April 2009 – December 2015, 58 patients (median age 54, range 33-83) were enrolled; 56 (97%) had measurable disease, and all had metastatic TNBC by local assessment. 33 (57%) patients completed induction; 22 (38%) came off study during induction; 3 (5%) continue on maintenance therapy. 4 patients discontinued therapy prior to first assessment. As of June 8, 2016, 53 patients (91%) have progressed. Median follow up for surviving patients is 14.5 months (range 4.1-65.4). Median PFS is 7.7 months (95% CI 5.7, 9.5). Of 56 patients with measurable disease, 38 (66%) had partial response (PR); 10 (17%) with stable disease for clinical benefit rate (CBR) of 86%. Median OS is 18.2 months (95% CI 16.3, 24.5). Most common grade 3-4 toxicities during induction were neutropenia [17 (29%), 1 grade 4], fatigue [13 (22%), all grade 3], leukopenia [7 (12%), all grade 3], and neuropathy [7 (12%), all grade 3]. Rash was most common ≥ grade 3 toxicity during maintenance [4 (7%), grade 3]. One patient experienced clinical CHF during maintenance month 16 requiring bevacizumab discontinuation. Conclusions: Nab-paclitaxel and bevacizumab followed by maintenance targeted therapy with bevacizumab and erlotinib was well tolerated. While the observed PFS did not meet pre-specified criteria of interest, the majority of patients experienced clinical benefit (86%) with 30 (57%) receiving maintenance targeted therapy. Correlative studies are ongoing. Supported by Genentech (OSI4266s), Celegene (AX-CL-BRST-PI-003828) and Janssen.

Citation Format: Specht JM, Gadi VK, Gralow JR, Korde LA, Linden HM, Salazar LG, Rodler ET, Cundy A, Buening BJ, Baker KK, Redman MW, Kurland BF, Garrison MA, Smith JC, vanHaelst C, Anderson JE. Combined targeted therapies for advanced triple negative breast cancer: A phase II trial of nab-paclitaxel and bevacizumab followed by maintenance targeted therapy with bevacizumab and erlotinib [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P4-22-11.

Abstract P4-02-05: Test-retest fidelity of FDG SUVmax in bone and non-boney metastatic breast cancer lesions in local area network PET/CT scanners

Background: Metabolic activity in lesions, measured by FDG-PET, is often used for assessing tumor aggressiveness and response to therapy. Patients may be scanned on different machines, so quantitative measurements should be reproducible. Reducing SUV variability in PET machines throughout a local network can aid in monitoring patient response to therapy and increase access to clinical trials.

Methods: Eighteen female patients with advanced or metastatic breast cancer underwent paired FDG PET/CT test-retest studies with 1-15 days between scans, and without interim change in treatment. Ten patients were studied in the same scanner and 8 patients were studied in 2 different scanners. Five different PET/CT scanners were used (2 GE DSTE, 2 Siemens (BioGraph 6 and mCT), 1 Philips Ingenuity TF). Each PET/CT scanner was calibrated using NIST-traceable reference sources to characterize and reduce variability. All of the images were interpreted by two separate reviewers. SUVmax values in lesions, corresponding normal tissue, and normal liver were collected. Linear mixed models with random intercept (patient effects) were fitted to compare differences in log(|SUVmax % difference|+.01) in multiple lesions per patient.

Results: SUVmax was assessed in a total of 130 lesions (75 bone). The median number of lesions per patient was 5 (range 1-17). Average SUVmax ranged from 1.0 to 18.2 (mean±SD = 6.0±3.2). The median SUVmax difference was 0.4 (8%) for 47 lesions imaged twice in the same scanner, and was 0.6 (13%) for 83 lesions imaged in two different scanners. In a multivariable linear mixed effects model, SUVmax for different scanners within the same institution did not differ more than for the same scanner (p=0.39), but repeat scans with different scanners and site personnel at had an average of 78% greater percentage difference in SUVmax than for the same scanner (p=0.009). In the same model, the average percent difference in SUVmax for bone lesions was estimated as 30% lower than for other sites (p=0.06, 95% confidence interval 0-50%). Examining normal liver uptake, the median SUVmean was 2.5 (range 1.9-3.1) with an median 6.5% difference between measurements (range 1.1%-23.7%) that did not appear to differ based on scanners used for repeat measurements (p=0.47).

Conclusions: The variability in quantitative FDG SUVmax between scans is modest, suggesting reliable reproducibility in appropriately calibrated settings. In our study, bone lesions had somewhat higher fidelity than other tumor sites. Additional studies will address variability in other cancer types. Careful calibration and monitoring of PET/CT scanners, and consistent imaging protocols are necessary in clinical trials that utilize quantitative PET/CT imaging in order to confidently interpret results.

Research Support: NIH grant U01-CA148131 and NCI-SAIC Contract 24XS036-004.

Citation Format: Linden HM, Peterson LM, Kurland B, Roberts T, Specht J, Shields AT, Novakova A, Christopfel R, Byrd D, Muzi M, Mankoff DA, Kinahan P. Test-retest fidelity of FDG SUVmax in bone and non-boney metastatic breast cancer lesions in local area network PET/CT scanners [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P4-02-05.

A virtual clinical trial comparing static versus dynamic PET imaging in measuring response to breast cancer therapy

We developed a method to evaluate variations in the PET imaging process in order to characterize the relative ability of static and dynamic metrics to measure breast cancer response to therapy in a clinical trial setting. We performed a virtual clinical trial by generating 540 independent and identically distributed PET imaging study realizations for each of 22 original dynamic fluorodeoxyglucose (¹⁸F-FDG) breast cancer patient studies pre- and post-therapy. Each noise realization accounted for known sources of uncertainty in the imaging process, such as biological variability and SUV uptake time. Four definitions of SUV were analyzed, which were SUVmax, SUVmean, SUVpeak, and SUV50%. We performed a ROC analysis on the resulting SUV and kinetic parameter uncertainty distributions to assess the impact of the variability on the measurement capabilities of each metric. The kinetic macro parameter, K _i , showed more variability than SUV (mean CV K _i   =  17%, SUV  =  13%), but K _i pre- and post-therapy distributions also showed increased separation compared to the SUV pre- and post-therapy distributions (mean normalized difference K _i   =  0.54, SUV  =  0.27). For the patients who did not show perfect separation between the pre- and post-therapy parameter uncertainty distributions (ROC AUC  <  1), dynamic imaging outperformed SUV in distinguishing metabolic change in response to therapy, ranging from 12 to 14 of 16 patients over all SUV definitions and uptake time scenarios (p  <  0.05). For the patient cohort in this study, which is comprised of non-high-grade ER+  tumors, K _i outperformed SUV in an ROC analysis of the parameter uncertainty distributions pre- and post-therapy. This methodology can be applied to different scenarios with the ability to inform the design of clinical trials using PET imaging.

Accrual Patterns for Clinical Studies Involving Quantitative Imaging: Results of an NCI Quantitative Imaging Network (QIN) Survey

Patient accrual is essential for the success of oncology clinical trials. Recruitment for trials involving the development of quantitative imaging biomarkers may face different challenges than treatment trials. This study surveyed investigators and study personnel for evaluating accrual performance and perceived barriers to accrual and for soliciting solutions to these accrual challenges that are specific to quantitative imaging-based trials. Responses for 25 prospective studies were received from 12 sites. The median percent annual accrual attained was 94.5% (range, 3%–350%). The most commonly selected barrier to recruitment (n = 11/25, 44%) was that “patients decline participation,” followed by “too few eligible patients” (n = 10/25, 40%). In a forced choice for the single greatest recruitment challenge, “too few eligible patients” was the most common response (n = 8/25, 32%). Quantitative analysis and qualitative responses suggested that interactions among institutional, physician, and patient factors contributed to accrual success and challenges. Multidisciplinary collaboration in trial design and execution is essential to accrual success, with attention paid to ensuring and communicating potential trial benefits to enrolled and future patients.

Estrogen Receptor Binding (18F-FES PET) and Glycolytic Activity (18F-FDG PET) Predict Progression-Free Survival on Endocrine Therapy in Patients with ER+ Breast Cancer

PURPOSE

18F-fluoroestradiol (FES) PET scans measure regional estrogen binding, and 18F-fluorodeoxyglucose (FDG) PET measures tumor glycolytic activity. We examined quantitative and qualitative imaging biomarkers of progression-free survival (PFS) in breast cancer patients receiving endocrine therapy.

EXPERIMENTAL DESIGN

Ninety patients with breast cancer from an estrogen receptor-positive (ER+), HER2- primary tumor underwent FES PET and FDG PET scans prior to endocrine therapy (63% aromatase inhibitor, 22% aromatase inhibitor and fulvestrant, 15% other). Eighty-four had evaluable data for PFS prediction.

RESULTS

Recursive partitioning with 5-fold internal cross-validation used both FES PET and FDG PET measures to classify patients into three distinct response groups. FDG PET identified 24 patients (29%) with low FDG uptake, suggesting indolent tumors. These patients had a median PFS of 26.1 months (95% confidence interval, 11.2-49.7). Of patients with more FDG-avid tumors, 50 (59%) had high average FES uptake, and 10 (12%) had low average FES uptake. These groups had median PFS of 7.9 (5.6-11.8) and 3.3 months (1.4-not evaluable), respectively. Patient and tumor features did not replace or improve the PET measures' prediction of PFS. Prespecified endocrine resistance classifiers identified in smaller cohorts did not individually predict PFS.

CONCLUSIONS

A wide range of therapy regimens are available for treatment of ER+ metastatic breast cancer, but no guidelines are established for sequencing these therapies. FDG PET and FES PET may help guide the timing of endocrine therapy and selection of targeted and/or cytotoxic chemotherapy. A multicenter trial is ongoing for external validation. Clin Cancer Res; 23(2); 407-15. ©2016 AACR.

Evaluation of Cross-Calibrated 68Ge/68Ga Phantoms for Assessing PET/CT Measurement Bias in Oncology Imaging for Single- and Multicenter Trials

Quantitative PET imaging is an important tool for clinical trials evaluating the response of cancers to investigational therapies. The standardized uptake value, used as a quantitative imaging biomarker, is dependent on multiple parameters that may contribute bias and variability. The use of long-lived, sealed PET calibration phantoms offers the advantages of known radioactivity activity concentration and simpler use than aqueous phantoms. We evaluated scanner and dose calibrator sources from two batches of commercially available kits, together at a single site and distributed across a local multicenter PET imaging network. We found that radioactivity concentration was uniform within the phantoms. Within the regions of interest drawn in the phantom images, coefficients of variation of voxel values were less than 2%. Across phantoms, coefficients of variation for mean signal were close to 1%. Biases of the standardized uptake value estimated with the kits varied by site and were seen to change in time by approximately ±5%. We conclude that these biases cannot be assumed constant over time. The kits provide a robust method to monitor PET scanner and dose calibrator biases, and resulting biases in standardized uptake values.

Functional Estrogen Receptor Imaging Before Neoadjuvant Therapy for Primary Breast Cancer

Estrogen receptor α (ERα) is a critical prognostic and predictive biomarker in breast cancer. ERα expression is used to determine whether patients should be treated with endocrine therapy, which is designed to block ERα signaling. Endocrine therapy given for 5-10 y after surgery improves progression-free and overall survival for patients with ER-positive primary breast cancer. However, disease recurrence and development of metastatic disease can occur despite appropriate treatment with endocrine therapy. Thus, a functional test performed at the time of initial diagnosis that can identify which patients would do well with endocrine therapy alone versus those who require adjuvant chemotherapy would be impactful for improving patient outcomes.

Quantitative Imaging in Cancer Clinical Trials

As anticancer therapies designed to target specific molecular pathways have been developed, it has become critical to develop methods to assess the response induced by such agents. Although traditional, anatomic CT, and MRI examinations are useful in many settings, increasing evidence suggests that these methods cannot answer the fundamental biologic and physiologic questions essential for assessment and, eventually, prediction of treatment response in the clinical trial setting, especially in the critical period soon after treatment is initiated. To optimally apply advances in quantitative imaging methods to trials of targeted cancer therapy, new infrastructure improvements are needed that incorporate these emerging techniques into the settings where they are most likely to have impact. In this review, we first elucidate the needs for therapeutic response assessment in the era of molecularly targeted therapy and describe how quantitative imaging can most effectively provide scientifically and clinically relevant data. We then describe the tools and methods required to apply quantitative imaging and provide concrete examples of work making these advances practically available for routine application in clinical trials. We conclude by proposing strategies to surmount barriers to wider incorporation of these quantitative imaging methods into clinical trials and, eventually, clinical practice. Our goal is to encourage and guide the oncology community to deploy standardized quantitative imaging techniques in clinical trials to further personalize care for cancer patients and to provide a more efficient path for the development of improved targeted therapies.

Imaging Diagnostic and Therapeutic Targets: Steroid Receptors in Breast Cancer

Estrogen receptor alpha (ERα) and progesterone receptor (PR) are important steroid hormone receptor biomarkers used to determine prognosis and to predict benefit from endocrine therapies for breast cancer patients. Receptor expression is routinely measured in biopsy specimens using immunohistochemistry, although such testing can be challenging, particularly in the setting of metastatic disease. ERα and PR can be quantitatively assayed noninvasively with PET. This approach provides the opportunity to assess receptor expression and function in real time, within the entire tumor, and across distant sites of metastatic disease. This article reviews the current evidence of ERα and PR PET imaging as predictive and early-response biomarkers for endocrine therapy.

Comparison of prone versus supine 18F-FDG-PET of locally advanced breast cancer: Phantom and preliminary clinical studies

PURPOSE

Previous studies have demonstrated how imaging of the breast with patients lying prone using a supportive positioning device markedly facilitates longitudinal and/or multimodal image registration. In this contribution, the authors' primary objective was to determine if there are differences in the standardized uptake value (SUV) derived from [(18)F]fluorodeoxyglucose (18F-FDG) positron emission tomography (PET) in breast tumors imaged in the standard supine position and in the prone position using a specialized positioning device.

METHODS

A custom positioning device was constructed to allow for breast scanning in the prone position. Rigid and nonrigid phantom studies evaluated differences in prone and supine PET. Clinical studies comprised 18F-FDG-PET of 34 patients with locally advanced breast cancer imaged in the prone position (with the custom support) followed by imaging in the supine position (without the support). Mean and maximum values (SUVpeak and SUVmax, respectively) were obtained from tumor regions-of-interest for both positions. Prone and supine SUV were linearly corrected to account for the differences in 18F-FDG uptake time. Correlation, Bland-Altman, and nonparametric analyses were performed on uptake time-corrected and uncorrected data.

RESULTS

SUV from the rigid PET breast phantom imaged in the prone position with the support device was 1.9% lower than without the support device. In the nonrigid PET breast phantom, prone SUV with the support device was 5.0% lower than supine SUV without the support device. In patients, the median (range) difference in uptake time between prone and supine scans was 16.4 min (13.4-30.9 min), which was significantly-but not completely-reduced by the linear correction method. SUVpeak and SUVmax from prone versus supine scans were highly correlated, with concordance correlation coefficients of 0.91 and 0.90, respectively. Prone SUVpeak and SUVmax were significantly lower than supine in both original and uptake time-adjusted data across a range of index times (P < < 0.0001, Wilcoxon signed rank test). Before correcting for uptake time differences, Bland-Altman analyses revealed proportional bias between prone and supine measurements (SUVpeak and SUVmax) that increased with higher levels of FDG uptake. After uptake time correction, this bias was significantly reduced (P < 0.01). Significant prone-supine differences, with regard to the spatial distribution of lesions relative to isocenter, were observed between the two scan positions, but this was poorly correlated with the residual (uptake time-corrected) prone-supine SUVpeak difference (P = 0.78).

CONCLUSIONS

Quantitative 18F-FDG-PET/CT of the breast in the prone position is not deleteriously affected by the support device but yields SUV that is consistently lower than those obtained in the standard supine position. SUV differences between scans arising from FDG uptake time differences can be substantially reduced, but not removed entirely, with the current correction method. SUV from the two scan orientations is quantitatively different and should not be assumed equivalent or interchangeable within the same subject. These findings have clinical relevance in that they underscore the importance of patient positioning while scanning as a clinical variable that must be accounted for with longitudinal PET measurement, for example, in the assessment of treatment response.

Abstract P5-01-02: Multimodality molecular imaging with dynamic 18F-fluorodeoxyglucose positron emission tomography (FDG PET) and MRI to evaluate response and resistance to neoadjuvant chemotherapy (NAC)

Background: Using quantitative FDG PET to measure glucose metabolism and perfusion, and dynamic contrast-enhanced (DCE) MRI to measure perfusion, we previously identified a metabolic signature for breast cancer resistant to NAC. This imaging signature is (1) persistent or increased tumor perfusion despite treatment, (2) an altered pattern of glucose kinetics in response to therapy, and (3) pre-therapy mismatch between tumor metabolism (MRFDG) and glucose delivery (K1) (high ratio of MRFDG/K1). These patterns predict poor response, early relapse and death independent of established prognostic factors, including pathologic response. Identification of factors associated with resistance or response to therapy is the translational goal of "Quantitative Dynamic PET and MRI in Breast Cancer Therapy," part of the Seattle Breast SPORE (1P50CA138293).

Methods: Patients (Pts) undergoing NAC for histologically confirmed breast cancer (stage II-III) were approached for this trial (CCIRB# 7587). FDG PET and DCE-MRI were obtained pre-therapy, 2-12 weeks after start of NAC (mid-therapy) and after completion of NAC. Breast biopsies were obtained pre-therapy and post-NAC. FDG PET included a dynamic scan with kinetic analysis. PET measures included SUVmax, MRFDG, K1, Ki, and Patlak. 3T DCE-MRI measurements included semi-quantitative vascular parameters of peak enhancement (PE), signal enhancement ratio (SER), washout fraction, functional tumor volume, and apparent diffusion coefficient (ADC) from diffusion-weighted MRI (DWI). Breast biopsies were assayed by immunohistochemistry and gene expression profiling. NAC was per physician's choice with most pts receiving weekly paclitaxel (with trastuzumab if HER2+) followed by doxorubicin/cyclophosphamide.

Results: 32 pts have completed the study. Pathologic complete response (pCR), defined as absence of invasive cancer in the breast, was observed in 9 (28%); near pCR defined as only microscopic residual invasive cancer in 3 (9%) more pts. Mid-therapy decline in SUVmax and K1 was associated with near pCR; (p-value 0.06, 0.04, respectively). Pre-therapy PET measures of MRFDG and K1 were not predictive of pCR. On MRI, pre-therapy PE (p=0.009), SER (p=0.01), washout fraction (p=0.02), ADC (p=0.08, trend) and mid-therapy change in volume (p=0.05) were each predictive of pCR. Gene profiling of pre-therapy biopsies showed correlation between high MRFDG/K1 ratio in basal and luminal B tumors.

Conclusions: Assessment of serial changes in tumor metabolism and perfusion by FDG PET and DCE-MRI is feasible in the clinic. Mid-therapy decline in metabolism and glucose delivery was predictive of pCR; consistent with prior retrospective series. Baseline DCE-MRI and DWI measures show promise to predict response, and associations of mid-therapy change in MR functional tumor volume with pCR agree with findings of another multisite clinical trial (ISPY). These imaging parameters may serve as useful biomarkers to inform future neoadjuvant trials. Integration of imaging data with gene expression profiling revealed that the pattern of metabolism in luminal B tumors was closer to that of the basal subtype compared to other ER-positive tumors.

Citation Format: Specht JM, Partridge S, Chai X, Novakova A, Peterson L, Shields A, Guenthoer J, Linden HM, Gralow JR, Gadi V, Korde L, Hills D, Hsu L, Hockenbery DM, Kinahan P, Mankoff DA, Porter PL. Multimodality molecular imaging with dynamic 18F-fluorodeoxyglucose positron emission tomography (FDG PET) and MRI to evaluate response and resistance to neoadjuvant chemotherapy (NAC). [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 P5-01-02.

Abstract P5-13-07: An investigator-initiated registry trial of simple oral therapy for low risk breast cancer

Background: Across multiple studies performed in several countries with widely instituted screening mammography programs at different intervals between exams, up to 19% of breast cancer identified is in patients whose disease would otherwise go undetected and not have caused any ill effect if left untreated. Recent advances in pathologic and multigene assays have demonstrated promise to better identify low risk breast cancer and appropriately tailor treatments. Nonetheless, most women who may have such low-risk, estrogen receptor expressing lesions continue to be offered only an aggressive treatment paradigm. This most commonly includes surgery and lymph node evaluation and, in the case of breast conservation, breast irradiation following surgery, with the option of endocrine therapy for 5-10 years.

Trial design: We propose a multi-center US registry study of post-menopausal, female breast cancer patients age 60 and older who will be managed 5 years with oral endocrine therapy for mammographically screen-detected, node-negative, unifocal invasive disease with low clinical grade, high estrogen/progesterone receptor expression, negative Her2 expression, Ki67 rate &lt;20%, and low-risk multigene expression analysis with Mammaprint Breast Cancer Recurrence Assay. Target lesions will be confirmed with a pre-treatment bilateral breast MRI and imaged routinely with standard mammography or ultrasound at 3-month intervals during months 1-36 and at 6-month intervals during months 37-60 to assess for disease response. Enrolled patients will have an ECOG performance status of 0-2. Medication history will be documented at routine follow-up visits.

Our primary objective will be to determine the frequency of conversion from a low-toxicity approach with oral endocrine therapy to conventional care with surgery +/- radiation therapy as a result of progression of disease or patient/provider choice. Progression of disease will be quantified objectively as &gt;20% growth of the target lesion as compared to baseline in imaging measurements. After 5 years of endocrine therapy sans disease progression, patients may elect to continue or stop treatment or convert to standard care.

Statistical methods: We will determine the conversion rate from oral therapy for any cause to conventional management (compliance). Compared to the most pessimistic assumed true-rate for compliance of 0.5, we predict &gt;90% power to detect a decrease of 0.1 in outcomes with an alpha of 5% (corresponds to a 95% Confidence Interval). Using descriptive statistics, we will also quantify for disease responses and progression-free survival. Our sample size will be ample for multiple sub-analyses including measurement of differences emanating from tertiary care versus local oncologic management, advanced imaging outcomes (if performed on any subset of patients), effect of type of endocrine therapy type (SERM vs AI), and effect of age and/or comorbidity severity interaction.

Accrual: Clinic sites with large patient cohorts are now being selected nationwide to enroll and manage patients' disease with endocrine treatment only. We will select up to 20 sites and enroll 300 patients with low-risk disease.

Citation Format: Gadi VK, Preusse C, Calhoun KE, Kim J, Linden HM, Rendi M, Etzioni RB, Gooley T, Lyman G, Stork L, van der Baan B, Barth N, Rahbar H. An investigator-initiated registry trial of simple oral therapy for low risk 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 P5-13-07.

Phase I Study of Veliparib (ABT-888) Combined with Cisplatin and Vinorelbine in Advanced Triple-Negative Breast Cancer and/or BRCA Mutation-Associated Breast Cancer

PURPOSE

Cisplatin is synergistic with vinorelbine and the PARP inhibitor veliparib, and has antineoplastic activity in triple-negative breast cancer (TNBC) and BRCA mutation-associated breast cancer. This phase I study assessed veliparib with cisplatin and vinorelbine.

EXPERIMENTAL DESIGN

A 3+3 dose-escalation design evaluated veliparib administered twice daily for 14 days with cisplatin (75 mg/m(2) day 1) and vinorelbine (25 mg/m(2) days 1, 8) every 21 days, for 6 to 10 cycles, followed by veliparib monotherapy. Pharmacokinetics, measurement of poly(ADP-ribose) in peripheral blood mononuclear cells, and preliminary efficacy were assessed. IHC and gene-expression profiling were evaluated as potential predictors of response.

RESULTS

Forty-five patients enrolled in nine dose cohorts plus five in an expansion cohort at the highest dose level and recommended phase II dose, 300 mg twice daily. The MTD of veliparib was not reached. Neutropenia (36%), anemia (30%), and thrombocytopenia (12%) were the most common grade 3/4 adverse events. Best overall response for 48 patients was radiologic response with 9-week confirmation for 17 (35%; 2 complete, 15 partial), and stable disease for 21 (44%). Germline BRCA mutation presence versus absence was associated with 6-month progression-free survival [PFS; 10 of 14 (71%) vs. 8 of 27 (30%), mid-P = 0.01]. Median PFS for all 50 patients was 5.5 months (95% confidence interval, 4.1-6.7).

CONCLUSIONS

Veliparib at 300 mg twice daily combined with cisplatin and vinorelbine is well tolerated with encouraging response rates. A phase II randomized trial is planned to assess veliparib's contribution to cisplatin chemotherapy in metastatic TNBC and BRCA mutation-associated breast cancer. Clin Cancer Res; 22(12); 2855-64. ©2016 AACR.

Multicenter Clinical Trials Using 18F-FDG PET to Measure Early Response to Oncologic Therapy: Effects of Injection-to-Acquisition Time Variability on Required Sample Size

Uptake time (interval between tracer injection and image acquisition) affects the SUV measured for tumors in (18)F-FDG PET images. With dissimilar uptake times, changes in tumor SUVs will be under- or overestimated. This study examined the influence of uptake time on tumor response assessment using a virtual clinical trials approach.

METHODS

Tumor kinetic parameters were estimated from dynamic (18)F-FDG PET scans of breast cancer patients and used to simulate time-activity curves for 45-120 min after injection. Five-minute uptake time frames followed 4 scenarios: the first was a standardized static uptake time (the SUV from 60 to 65 min was selected for all scans), the second was uptake times sampled from an academic PET facility with strict adherence to standardization protocols, the third was a distribution similar to scenario 2 but with greater deviation from standards, and the fourth was a mixture of hurried scans (45- to 65-min start of image acquisition) and frequent delays (58- to 115-min uptake time). The proportion of out-of-range scans (<50 or >70 min, or >15-min difference between paired scans) was 0%, 20%, 44%, and 64% for scenarios 1, 2, 3, and 4, respectively. A published SUV correction based on local linearity of uptake-time dependence was applied in a separate analysis. Influence of uptake-time variation was assessed as sensitivity for detecting response (probability of observing a change of ≥30% decrease in (18)F-FDG PET SUV given a true decrease of 40%) and specificity (probability of observing an absolute change of <30% given no true change).

RESULTS

Sensitivity was 96% for scenario 1, and ranged from 73% for scenario 4 (95% confidence interval, 70%-76%) to 92% (90%-93%) for scenario 2. Specificity for all scenarios was at least 91%. Single-arm phase II trials required an 8%-115% greater sample size for scenarios 2-4 than for scenario 1. If uptake time is known, SUV correction methods may raise sensitivity to 87%-95% and reduce the sample size increase to less than 27%.

CONCLUSION

Uptake-time deviations from standardized protocols occur frequently, potentially decreasing the performance of (18)F-FDG PET response biomarkers. Correcting SUV for uptake time improves sensitivity, but algorithm refinement is needed. Stricter uptake-time control and effective correction algorithms could improve power and decrease costs for clinical trials using (18)F-FDG PET endpoints.

Effect of 18F-FDG uptake time on lesion detectability in PET imaging of early stage breast cancer

Prior reports have suggested that delayed FDG-PET oncology imaging can improve the contrast-to-noise ratio (CNR) for known lesions. Our goal was to estimate realistic bounds for lesion detectability for static measurements with one to four hours between FDG injection and image acquisition. Tumor and normal tissue kinetic model parameters were estimated from dynamic PET studies of patients with early stage breast cancer. These were used to generate time-activity curves (TACs) out to four hours, for which we assumed both nonreversible and reversible models with different rates of FDG dephosphorylation (k4). For each pair of tumor and normal tissue TACs, 600 PET sinogram realizations were generated, and images were reconstructed using OSEM. Test statistics for each tumor and normal tissue region of interest were output from the computer model observers and evaluated using an ROC analysis with the calculated AUC providing a measure of lesion detectability. For the nonreversible model (k4 = 0), the AUC increased in 11/23 (48%) of patients for one to two hours after the current standard post-radiotracer injection imaging window of one hour. This improvement was driven by increased tumor/normal tissue contrast before the impact of increased noise due to radiotracer decay began to dominate the imaging signal. As k4 was increased from 0 to 0.01 min-1, the time of maximum detectability shifted earlier, as the decreasing FDG concentration in the tumor lowered the CNR. These results imply that delayed PET imaging may reveal low-conspicuity lesions that would have otherwise gone undetected.