Cost-effectiveness of MRI for breast cancer screening in BRCA1/2 mutation carriers

Improving signal-to-noise ratio by maximal convolution of longitudinal and transverse magnetization components in MRI: application to the breast cancer detection

PURPOSE

The extraction of information from images provided by medical imaging systems may be employed to obtain the specific objectives in the various fields. The quantity of signal to noise ratio (SNR) plays a crucial role in displaying the image details. The higher the SNR value, the more the information is available.

METHODS

In this study, a new function has been formulated using the appropriate suggestions on convolutional combination of the longitudinal and transverse magnetization components related to the relaxation times of T1 and T2 in MRI, where by introducing the distinct index on the maximum value of this function, the new maps are constructed toward the best SNR. Proposed functions were analytically simulated using Matlab software and evaluated with respect to various relaxation times. This proposed method can be applied to any medical images. For instance, the T1- and T2-weighted images of the breast indicated in the reference [35] were selected for modelling and construction of the full width at x maximum (FWxM) map at the different values of x-parameter from 0.01 to 0.955 at 0.035 and 0.015 intervals. The range of x-parameter is between zero and one. To determine the maximum value of the derived SNR, these intervals have been first chosen arbitrarily. However, the smaller this interval, the more precise the value of the x-parameter at which the signal to noise is maximum.

RESULTS

The results showed that at an index value of x = 0.325, the new map of FWxM (0.325) will be constructed with a maximum derived SNR of 22.7 compared to the SNR values of T1- and T2-maps by 14.53 and 17.47, respectively.

CONCLUSION

By convolving two orthogonal magnetization vectors, the qualified images with higher new SNR were created, which included the image with the best SNR. In other words, to optimize the adoption of MRI technique and enable the possibility of wider use, an optimal and cost-effective examination has been suggested. Our proposal aims to shorten the MRI examination to further reduce interpretation times while maintaining primary sensitivity.

SIGNIFICANCE

Our findings may help to quantitatively identify the primary sources of each type of solid and sequential cancer.

Economic evaluation of breast MRI in screening - a systematic review and basic approach to cost-effectiveness analyses

Background

Economic evaluations have become an accepted methodology for decision makers to allocate resources in healthcare systems. Particularly in screening, where short-term costs are associated with long-term benefits, and adverse effects of screening intermingle, cost-effectiveness analyses provide a means to estimate the economic value of screening.

Purpose

To introduce the methodology of economic evaluations and to review the existing evidence on cost-effectiveness of MR-based breast cancer screening.

Materials and methods

The various concepts and techniques of economic evaluations critical to the interpretation of cost-effectiveness analyses are briefly introduced. In a systematic review of the literature, economic evaluations from the years 2000-2022 are reviewed.

Results

Despite a considerable heterogeneity in the reported input variables, outcome categories and methodological approaches, cost-effectiveness analyses report favorably on the economic value of breast MRI screening for different risk groups, including both short- and long-term costs and outcomes.

Conclusion

Economic evaluations indicate a strongly favorable economic value of breast MRI screening for women at high risk and for women with dense breast tissue.

Health Benefits and Cost-Effectiveness of Children's Oncology Group Breast Cancer Screening Guidelines for Chest-Irradiated Hodgkin Lymphoma Survivors

PURPOSE

To evaluate the outcomes and cost-effectiveness of the Children's Oncology Group Guideline recommendation for breast cancer (BC) screening using mammography (MAM) and breast magnetic resonance imaging (MRI) in female chest-irradiated childhood Hodgkin lymphoma (HL) survivors. Digital breast tomosynthesis (DBT), increasingly replacing MAM in practice, was also examined.

METHODS

Life years (LYs), quality-adjusted LYs (QALYs), BC mortality, health care costs, and false-positive screen frequencies of undergoing annual MAM, DBT, MRI, MAM + MRI, and DBT + MRI from age 25 to 74 years were estimated by microsimulation. BC risks and non-BC mortality were estimated from female 5-year survivors of HL in the Childhood Cancer Survivor Study and the US population. Test performance of MAM and MRI was synthesized from HL studies, and that of DBT from the general population. Costs (2017 US dollars [USD]) and utility weights were obtained from the medical literature. Incremental cost-effectiveness ratios (ICERs) were calculated.

RESULTS

With 100% screening adherence, annual BC screening extended LYs by 0.34-0.46 years over no screening. If the willingness-to-pay threshold to gain a quality-adjusted LY was ICER < $100,000 USD, annual MAM at age 25-74 years was the only cost-effective strategy. When nonadherence was taken into consideration, only annual MAM at age 30-74 years (ICER = $56,972 USD) was cost-effective. Supplementing annual MAM with MRI costing $545 USD was not cost-effective under either adherence condition. If MRI costs were reduced to $300 USD, adding MRI to annual MAM at age 30-74 years could become more cost-effective, particularly in the reduced adherence condition (ICER = $133,682 USD).

CONCLUSION

Annual BC screening using MAM at age 30-74 years is effective and cost-effective in female chest-irradiated HL survivors. Although annual adjunct MRI is not cost-effective at $545 USD cost, it could become cost-effective as MRI cost is reduced, a plausible scenario with the emergent use of abbreviated MRI.

Cost-Effectiveness Analysis of Imaging Modalities for Breast Cancer Surveillance Among BRCA1/2 Mutation Carriers: A Systematic Review

Background

BRCA1/2 mutation carriers are suggested with regular breast cancer surveillance screening strategies using mammography with supplementary MRI as an adjunct tool in Western countries. From a cost-effectiveness perspective, however, the benefits of screening modalities remain controversial among different mutated genes and screening schedules.

Methods

We searched the MEDLINE/PubMed, Embase, Cochrane Library, Scopus, and Web of Science databases to collect and compare the results of different cost-effectiveness analyses. A simulated model was used to predict the impact of screening strategies in the target group on cost, life-year gained, quality-adjusted life years, and incremental cost-effectiveness ratio (ICER).

Results

Nine cost-effectiveness studies were included. Combined mammography and MRI strategy is cost-effective in BRCA1 mutation carriers for the middle-aged group (age 35 to 54). BRCA2 mutation carriers are less likely to benefit from adjunct MRI screening, which implies that mammography alone would be sufficient from a cost-effectiveness perspective, regardless of dense breast cancer.

Conclusions

Precision screening strategies among BRCA1/2 mutation carriers should be conducted according to the acceptable ICER, i.e., a combination of mammography and MRI for BRCA1 mutation carriers and mammography alone for BRCA2 mutation carriers.

Systematic Review Registration

PROSPERO, identifier CRD42020205471.

Cost-Effectiveness of Magnetic Resonance Imaging Screening for Women With Extremely Dense Breast Tissue

BACKGROUND

Extremely dense breast tissue is associated with increased breast cancer risk and limited sensitivity of mammography. The DENSE trial showed that additional magnetic resonance imaging (MRI) screening in women with extremely dense breasts resulted in a substantial reduction in interval cancers. The cost-effectiveness of MRI screening for these women is unknown.

METHODS

We used the MISCAN-breast microsimulation model to simulate several screening protocols containing mammography and/or MRI to estimate long-term effects and costs. The model was calibrated using results of the DENSE trial and adjusted to incorporate decreases in breast density with increasing age. Screening strategies varied in the number of MRIs and mammograms offered to women ages 50-75 years. Outcomes were numbers of breast cancers, life-years, quality-adjusted life-years (QALYs), breast cancer deaths, and overdiagnosis. Incremental cost-effectiveness ratios (ICERs) were calculated (3% discounting), with a willingness-to-pay threshold of €22 000.

RESULTS

Calibration resulted in a conservative fit of the model regarding MRI detection. Both strategies of the DENSE trial were dominated (biennial mammography; biennial mammography plus MRI). MRI alone every 4 years was cost-effective with €15 620 per QALY. Screening every 3 years with MRI alone resulted in an incremental cost-effectiveness ratio of €37 181 per QALY. All strategies with mammography and/or a 2-year interval were dominated because other strategies resulted in more additional QALYs per additional euro. Alternating mammography and MRI every 2 years was close to the efficiency frontier.

CONCLUSIONS

MRI screening is cost-effective for women with extremely dense breasts, when applied at a 4-year interval. For a willingness to pay more than €22 000 per QALY gained, MRI at a 3-year interval is cost-effective as well.

No Association of Early-Onset Breast or Ovarian Cancer with Early-Onset Cancer in Relatives in BRCA1 or BRCA2 Mutation Families

According to clinical guidelines, the occurrence of very early-onset breast cancer (VEO-BC) (diagnosed ≤ age 30 years) or VEO ovarian cancer (VEO-OC) (diagnosed ≤ age 40 years) in families with BRCA1 or BRCA2 mutation (BRCAm) prompts advancing the age of risk-reducing strategies in relatives. This study aimed to assess the relation between the occurrence of VEO-BC or VEO-OC in families with BRCAm and age at BC or OC diagnosis in relatives. We conducted a retrospective multicenter study of 448 consecutive families with BRCAm from 2003 to 2018. Mean age and 5-year–span distribution of age at BC or OC in relatives were compared in families with or without VEO-BC or VEO-OC. Conditional probability calculation and Cochran–Mantel–Haenszel chi-square tests were used to investigate early-onset cancer occurrence in relatives of VEO-BC and VEO-OC cases. Overall, 15% (19/245) of families with BRCA1m and 9% (19/203) with BRCA2m featured at least one case of VEO-BC; 8% (37/245) and 2% (2/203) featured at least one case of VEO-OC, respectively. The cumulative prevalence of VEO-BC was 5.1% (95% CI 3.6–6.6) and 2.5% (95% CI 1.4–3.6) for families with BRCA1m and BRCA2m, respectively. The distribution of age and mean age at BC diagnosis in relatives did not differ by occurrence of VEO-BC for families with BRCA1m or BRCA2m. Conditional probability calculations did not show an increase of early-onset BC in VEO-BC families with BRCA1m or BRCA2m. Conversely, the probability of VEO-BC was not increased in families with early-onset BC. VEO-BC or VEO-OC occurrence may not be related to young age at BC or OC onset in relatives in families with BRCAm. This finding—together with a relatively high VEO-BC risk for women with BRCAm—advocates for MRI breast screening from age 25 regardless of family history.

Canadian cost-effectiveness model of BRCA-driven surgical prevention of breast/ovarian cancers compared to treatment if cancer develops

OBJECTIVES

To assess the cost effectiveness from a Canadian perspective of index patient germline BRCA testing and then, if positive, family members with subsequent risk-reducing surgery (RRS) in as yet unaffected mutation carriers compared with no testing and treatment of cancer when it develops.

METHODS

A patient level simulation was developed comparing outcomes between two groups using Canadian data. Group 1: no mutation testing with treatment if cancer developed. Group 2: cascade testing (index patient BRCA tested and first-/second-degree relatives tested if index patient/first-degree relative is positive) with RRS in carriers. End points were the incremental cost-effectiveness ratio (ICER) and budget impact.

RESULTS

There were 29,102 index patients: 2,786 ovarian cancer and 26,316 breast cancer (BC). Using the base-case assumption of 44 percent and 21 percent of women with a BRCA mutation receiving risk-reducing bilateral salpingo-oophorectomy and risk-reducing mastectomy, respectively, testing was cost effective versus no testing and treatment on cancer development, with an ICER of CAD 14,942 (USD 10,555) per quality-adjusted life-year (QALY), 127 and 104 fewer cases of ovarian and BC, respectively, and twenty-one fewer all-cause deaths. Testing remained cost effective versus no testing at the commonly accepted North American threshold of approximately CAD 100,000 (or USD 100,000) per QALY gained in all scenario analyses, and cost effectiveness improved as RRS uptake rates increased.

CONCLUSIONS

Prevention via testing and RRS is cost effective at current RRS uptake rates; however, optimization of uptake rates and RRS will increase cost effectiveness and can provide cost savings.

Magnetic Resonance Imaging in Screening of Breast Cancer

Magnetic Resonance (MR) imaging is the most sensitive modality for breast cancer detection but is currently limited to screening women at high risk due to limited specificity and test accessibility. However, specificity of MR imaging improves with successive rounds of screening, and abbreviated approaches have the potential to increase access and decrease cost. There is growing evidence to support supplemental MR imaging in moderate-risk women, and current guidelines continue to evolve. Functional imaging has the potential to maximize survival benefit of screening. Leveraging MR imaging as a possible primary screening tool is therefore also being investigated in average-risk women.

Technique and clinical applications of dual-energy contrast-enhanced digital mammography (CEDM) in breast cancer evaluation: a pictorial essay

This pictorial essay illustrates an overview of the basic technique used in acquiring dual-energy contrast-enhanced digital mammography (CEDM) images and its potential clinical applications in regular practice. CEDM may be used as a low-cost alternative to magnetic resonance imaging (MRI), as a problem-solving tool in clinical practice and for therapeutic planning of breast cancer, which may include high-risk screening, dense breast evaluation, mammographically equivocal lesions, local staging, treatment response evaluation, and post treatment follow-up. We share our experience of CEDM at a tertiary care cancer hospital.

Cost-effectiveness of preoperative magnetic resonance imaging to optimize surgery in ductal carcinoma in situ of the breast

PURPOSE

Complete surgical excision is the main factor for successful breast-conserving surgery in patients with ductal carcinoma in situ (DCIS) of the breast. Preoperative magnetic resonance imaging (MRI) may allow surgery optimization in this indication. From an economic standpoint, systematic preoperative MRI is associated with an extra cost, which may be offset by a decrease in the number of re-interventions. We performed an economic evaluation alongside IRCIS randomised controlled trial (NCT01112254) to determine whether systematic preoperative MRI in DCIS is a cost-effective strategy.

METHODS

360 patients were included in IRCIS trial. Costs were assessed from the French national health insurance perspective. Resource use was prospectively collected during a 6-month period after randomisation. We estimated the mean cost per averted re-intervention.

RESULTS

Despite extra costs due to MRI and additional biopsies, difference in total costs between arms was not statistically significant (mean cost of €9980 in MRI arm and €9682 in no MRI arm, cost difference: €298 [CI95% : -470; 1063]). There was a non-significant decrease in the rate of re-hospitalisations for positive or close margins (20% in MRI arm versus 27% in No MRI arm, difference -7% [CI95% : -17; 3]). At a willingness to pay of €500 to avert a re-intervention, the probability that MRI strategy is cost-effective was 93%.

CONCLUSION

Systematic preoperative MRI in patients with DCIS of the breast may be a cost-effective strategy. However, the modest clinical benefit associated with such a strategy limits the interest for this procedure in routine practice given the current MRI techniques.

Screening in patients with increased risk of breast cancer (part 1): pros and cons of MRI screening

Screening plays an important role in women with a high risk of breast cancer. Given this population's high incidence of breast cancer and younger age of onset compared to the general population, it is recommended that screening starts earlier. There is ample evidence that magnetic resonance imaging (MRI) is the most sensitive diagnostic tool, and American and the European guidelines both recommend annual MRI screening (with supplementary annual mammography) as the optimum screening modality. Nevertheless, the current guidelines do not totally agree about the recommendations for MRI screening in some subgroups of patients. The first part of this article on screening in women with increased risk of breast cancer reviews the literature to explain and evaluate the advantages of MRI screening compared to screening with mammography alone: increased detection of smaller cancers with less associated lymph node involvement and a reduction in the rate of interval cancers, which can have an impact on survival and mortality (with comparable effects to other preventative measures). At the same time, however, we would like to reflect on the drawbacks of MRI screening that affect its applicability.

Recommendations for Advancing the Diagnosis and Management of Hereditary Breast and Ovarian Cancer in Brazil

PURPOSE

The objective of this review was to address the barriers limiting access to genetic cancer risk assessment and genetic testing for individuals with suspected hereditary breast and ovarian cancer (HBOC) through a review of the diagnosis and management steps of HBOC.

METHODS

A selected panel of Brazilian experts in fields related to HBOC was provided with a series of relevant questions to address before the multiday conference. During this conference, each narrative was discussed and edited by the entire group, through numerous drafts and rounds of discussion, until a consensus was achieved.

RESULTS

The authors propose specific and realistic recommendations for improving access to early diagnosis, risk management, and cancer care of HBOC specific to Brazil. Moreover, in creating these recommendations, the authors strived to address all the barriers and impediments mentioned in this article.

CONCLUSION

There is a great need to expand hereditary cancer testing and counseling in Brazil, and changing current policies is essential to accomplishing this goal. Increased knowledge and awareness, together with regulatory actions to increase access to this technology, have the potential to improve patient care and prevention and treatment efforts for patients with cancer across the country.

Combination of an ultrafast TWIST-VIBE Dixon sequence protocol and diffusion-weighted imaging into an accurate easily applicable classification tool for masses in breast MRI

OBJECTIVES

This study aimed to develop a tool for the classification of masses in breast MRI, based on ultrafast TWIST-VIBE Dixon (TVD) dynamic sequences combined with DWI. TVD sequences allow to abbreviate breast MRI protocols, but provide kinetic information only on the contrast wash-in, and because of the lack of the wash-out kinetics, their diagnostic value might be hampered. A special focus of this study was thus to maintain high diagnostic accuracy in lesion classification.

MATERIALS AND METHODS

Sixty-one patients who received breast MRI between 02/2014 and 04/2015 were included, with 83 reported lesions (60 malignant). Our institute's standard breast MRI protocol was complemented by an ultrafast TVD sequence. ADC and peak enhancement of the TVD sequences were integrated into a generalised linear model (GLM) for malignancy prediction. For comparison, a second GLM was calculated using ADC and conventional DCE curve type. The resulting GLMs were evaluated for standard diagnostic parameters. For easy application of the GLMs, nomograms were created.

RESULTS

The GLM based on peak enhancement of the TVD and ADC was as equally accurate as the GLM based on conventional DCE and ADC, with no significant differences (sensitivity, 93.3%/93.3%; specificity, 91.3%/87.0%; PPV, 96.6%/94.9%; NPV, 84.0%/83.3%; all, p ≥ 0.315).

CONCLUSIONS

This study presents a method to integrate ultrafast TVD sequences into a breast MRI protocol, allowing a reduction of the examination time while maintaining diagnostic accuracy. A GLM based on the combination of TVD-derived peak enhancement and ADC provides high diagnostic accuracy, and can be easily applied using a nomogram.

KEY POINTS

• Ultrafast TWIST-VIBE Dixon sequence protocols in combination with diffusion-weighted imaging allow to shorten breast MRI examinations, while diagnostic accuracy is maintained. • Integrating peak enhancement from the TWIST-VIBE Dixon sequence and the apparent diffusion coefficient into a generalised linear model provides a comprehensible image evaluation approach. • This approach is further facilitated by nomograms.

The cost-effectiveness of mammography-based female breast cancer screening in Canadian populations: a systematic review.. [DOI: 10.1101/2020.01.18.20018044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0]

Introduction

Mammography-based breast cancer screening is an important aspect of female breast cancer prevention within the Canadian healthcare system. The current literature on female breast cancer screening is largely focused on the health outcomes that result from screening. There is comparatively little data on the cost-effectiveness of the screening. Therefore, this paper sought to conduct a systematic review of the literature on the cost effectiveness of mammography-based breast cancer screening within female Canadian populations.

Materials and methods

A systematic review was performed in the PubMed database to identify all studies published within the last 10 years that addressed breast cancer screening and evaluate cost-effectiveness in a Canadian population.

Results

The search yielded five studies for inclusion, only three of which were applicable to average-risk Canadian women. The benefits of mortality reduction rose approximately linearly with costs, while costs were linearly dependent on the number of lifetime screens per woman. Moreover, triennial screening for average-risk women aged 50-69 years was found to be the most cost-effective in terms of cost per quality adjusted life year. The use of MRI in conjunction with mammography for women with the BRCA 1/2 mutation was found to be cost-effective while annual mammography-based screening for women with dense breasts was found to be cost-ineffective.

Conclusion

In spite of the growing interest to enhance breast cancer screening programs, analyses of the cost-effectiveness of mammography-based screening within Canadian populations are scarcely reported and have heterogeneous methodologies. The existing data suggests that Canada’s current breast cancer screening policy to screen average-risk women aged 50-74, biennially or triennially is cost-effective. These findings could be of interest to health policy makers when making decisions regarding resource allocation; however, further studies in this field are required in order to make stronger recommendations regarding cost-effectiveness.

Cost-Utility of Early Breast Cancer Surveillance in Survivors of Thoracic Radiation-Treated Adolescent Hodgkin Lymphoma

BACKGROUND

Adolescent women treated for Hodgkin lymphoma (HL) are at increased risk of breast cancer (BC). We evaluate the cost-utility of eight high-risk BC surveillance strategies for this population, including the Children's Oncology Group guideline of same-day annual mammography and magnetic resonance imaging (MRI) beginning at age 25 years.

METHODS

A discrete event simulation model was used to simulate the life histories of a cohort of 500 000 25-year-old women treated for HL at age 15 years. We estimated BC incidence and mortality, life expectancy, quality-adjusted life-years (QALYs), health-care costs, and the relative cost-utility (incremental cost-utility ratio [ICUR]) under the eight assessed surveillance strategies. One-way sensitivity analysis enabled modeling of uncertainty evaluation. A publicly funded health-care payer perspective was adopted.

RESULTS

Costs across the eight screening strategies ranged from $32 643 to $43 739, whereas QALYs ranged from 24.419 to 24.480. In an incremental cost-effectiveness analysis, annual mammography beginning at age 25 years was associated with an ICUR of $43 000/QALY gained, annual MRI beginning at age 25 years with a switch to annual mammography at age 50 years had an ICUR of $148 000/QALY, and annual MRI beginning at age 25 years had an ICUR of $227 222/QALY. Among all assessed surveillance strategies, the differences in life expectancy were small.

CONCLUSIONS

Current high-risk BC surveillance guidelines do not reflect the most cost-effective strategy in survivors of adolescent HL. The results suggest that groups at high risk of BC may require high-risk surveillance guidelines that reflect their specific risk profile.

Abbreviated Magnetic Resonance Imaging (MRI) for Breast Cancer Screening: Rationale, Concept, and Transfer to Clinical Practice

Given the increasing understanding of cancer as a heterogeneous group of diseases, detection methods should offer a sensitivity profile that ensures perfect sensitivity for biologically important cancers while screening out self-limiting pseudocancers. However, mammographic screening is biased toward detection of ductal carcinoma in situ and slowly growing cancers-and thus frequently fails to detect biologically aggressive cancers. This explains the persistently high rates of interval cancers and high rates of breast cancer mortality observed in spite of decades of mammographic screening. Magnetic resonance imaging (MRI), in contrast, has a sensitivity profile that matches clinical needs. Conventional MRI is not suitable for population-wide screening due to high cost, limited tolerability, and lack of availability. We introduced abbreviated MRI in 2014. Abbreviated MRI will change the way MRI is used in clinical medicine. This article describes the rationale to use MRI in general, and abbreviated MRI in particular, for breast cancer screening.

Association of Retrospective Peer Review and Positive Predictive Value of Magnetic Resonance Imaging-Guided Vacuum-Assisted Needle Biopsies of Breast

Objective

To evaluate the association between retrospective peer review of breast magnetic resonance imaging-guided vacuum-assisted needle biopsies and positive predictive value of subsequent magnetic resonance imaging-guided biopsies.

Materials and Methods

In January, 2015, a weekly conference was initiated in our institution to evaluate all breast magnetic resonance imaging-guided vacuum-assisted needle biopsies performed over January 1, 2014-December 31, 2015. During this weekly conferences, breast dynamic contrast-enhanced magnetic resonance imaging findings of 6 anonymized cases were discussed and then the faculty voted on whether they agree with the biopsy indication, accurate sampling and radiology-pathology correlation. We retrospectively reviewed and compared the magnetic resonance imaging indication, benign or malignant pathology rates, lesion types and the positive predictive value of magnetic resonance imaging-guided vacuum-assisted needle biopsy in the years before and after initiating this group peer review.

Results

The number of dynamic contrast-enhanced magnetic resonance imaging and magnetic resonance imaging-guided vacuum-assisted needle biopsies before and after initiating the review were 1447 vs 1596 (p=0.0002), and 253 (17.5%) vs 203 (12.7%) (p=0.04), respectively. There was a significant decrease in the number of benign biopsies in 2015 (n=104) compared to 2014 (n=154, p=0.04). The positive predictive value of magnetic resonance imaging-guided biopsy significantly increased after group review was implemented (Positive predictive value in 2014=%39.1 and positive predictive value in 2015=%48.8) (p=0.03), although the indications (p=0.49), history of breast cancer (p=0.14), biopsied magnetic resonance imaging lesion types (p=0.53) were not different. Less surgical excision was performed on magnetic resonance imaging-guided vacuum-assisted needle biopsy identified high-risk lesions in 2015 (p=0.25).

Conclusion

Our study showed an association between retrospective peer review of past biopsies and increased positive predictive value of magnetic resonance imaging-guided vacuum-assisted needle biopsies in our institution.

Multireader Study on the Diagnostic Accuracy of Ultrafast Breast Magnetic Resonance Imaging for Breast Cancer Screening

OBJECTIVES

Breast cancer screening using magnetic resonance imaging (MRI) has limited accessibility due to high costs of breast MRI. Ultrafast dynamic contrast-enhanced breast MRI can be acquired within 2 minutes. We aimed to assess whether screening performance of breast radiologist using an ultrafast breast MRI-only screening protocol is as good as performance using a full multiparametric diagnostic MRI protocol (FDP).

MATERIALS AND METHODS

The institutional review board approved this study, and waived the need for informed consent. Between January 2012 and June 2014, 1791 consecutive breast cancer screening examinations from 954 women with a lifetime risk of more than 20% were prospectively collected. All women were scanned using a 3 T protocol interleaving ultrafast breast MRI acquisitions in a full multiparametric diagnostic MRI protocol consisting of standard dynamic contrast-enhanced sequences, diffusion-weighted imaging, and T2-weighted imaging. Subsequently, a case set was created including all biopsied screen-detected lesions in this period (31 malignant and 54 benign) and 116 randomly selected normal cases with more than 2 years of follow-up. Prior examinations were included when available. Seven dedicated breast radiologists read all 201 examinations and 153 available priors once using the FDP and once using ultrafast breast MRI only in 2 counterbalanced and crossed-over reading sessions.

RESULTS

For reading the FDP versus ultrafast breast MRI alone, sensitivity was 0.86 (95% confidence interval [CI], 0.81-0.90) versus 0.84 (95% CI, 0.78-0.88) (P = 0.50), specificity was 0.76 (95% CI, 0.74-0.79) versus 0.82 (95% CI, 0.79-0.84) (P = 0.002), positive predictive value was 0.40 (95% CI, 0.36-0.45) versus 0.45 (95% CI, 0.41-0.50) (P = 0.14), and area under the receiver operating characteristics curve was 0.89 (95% CI, 0.82-0.96) versus 0.89 (95% CI, 0.82-0.96) (P = 0.83). Ultrafast breast MRI reading was 22.8% faster than reading FDP (P < 0.001). Interreader agreement is significantly better for ultrafast breast MRI (κ = 0.730; 95% CI, 0.699-0.761) than for the FDP (κ = 0.665; 95% CI, 0.633-0.696).

CONCLUSIONS

Breast MRI screening using only an ultrafast breast MRI protocol is noninferior to screening with an FDP and may result in significantly higher screening specificity and shorter reading time.

Intensive Surveillance with Biannual Dynamic Contrast-Enhanced Magnetic Resonance Imaging Downstages Breast Cancer in BRCA1 Mutation Carriers

PURPOSE

To establish a cohort of high-risk women undergoing intensive surveillance for breast cancer.Experimental Design: We performed dynamic contrast-enhanced MRI every 6 months in conjunction with annual mammography (MG). Eligible participants had a cumulative lifetime breast cancer risk ≥20% and/or tested positive for a pathogenic mutation in a known breast cancer susceptibility gene.

RESULTS

Between 2004 and 2016, we prospectively enrolled 295 women, including 157 mutation carriers (75 BRCA1, 61 BRCA2); participants' mean age at entry was 43.3 years. Seventeen cancers were later diagnosed: 4 ductal carcinoma in situ (DCIS) and 13 early-stage invasive breast cancers. Fifteen cancers occurred in mutation carriers (11 BRCA1, 3 BRCA2, 1 CDH1). Median size of the invasive cancers was 0.61 cm. No patients had lymph node metastasis at time of diagnosis, and no interval invasive cancers occurred. The sensitivity of biannual MRI alone was 88.2% and annual MG plus biannual MRI was 94.1%. The cancer detection rate of biannual MRI alone was 0.7% per 100 screening episodes, which is similar to the cancer detection rate of 0.7% per 100 screening episodes for annual MG plus biannual MRI. The number of recalls and biopsies needed to detect one cancer by biannual MRI were 2.8 and 1.7 in BRCA1 carriers, 12.0 and 8.0 in BRCA2 carriers, and 11.7 and 5.0 in non-BRCA1/2 carriers, respectively.

CONCLUSIONS

Biannual MRI performed well for early detection of invasive breast cancer in genomically stratified high-risk women. No benefit was associated with annual MG screening plus biannual MRI screening.See related commentary by Kuhl and Schrading, p. 1693.

Breast MRI ordering practices in a large health care network

The purpose of this study was to evaluate providers' ordering practices and perceptions of breast magnetic resonance imaging (MRI) in an academic network in order to better understand and educate a referral base. An online survey was distributed to primary care providers (PCPs) and specialists in our hospital and community practices. Questions included provider demographics, current ordering practices, challenges to ordering, and perceptions about breast MRI. Of 525 ordering providers, 134 responded (26% response rate). Of 134 providers, 57 (42%) order breast MRI in practice. Of those who do not, the most consistent reason was a lack of familiarity with the use of breast MRI (32/77 [42%] of cases). Of 57 cases, 45 (79%) order less than 10 exams annually. The most frequent indication is for high-risk screening (40/47 [84%]). PCPs order fewer breast MRI compared with specialists (P = 0.01). Both PCPs and specialists have mixed perceptions of the clinical utility of breast MRI. However, 30% of all providers are ordering more breast MRI since the enactment of breast density legislation in Massachusetts. Furthermore, 29% report they would order breast MRI more often to screen women with dense breasts if there was a low cost option. Referring provider surveys are useful tools for assessing a radiology practice. Our study suggests a growing clinical interest in breast MRI for screening; however, there is a need for provider education on the clinical utility of breast MRI. Increasing the radiologist's role in targeted educational interventions may help improve awareness and lead to more appropriate utilization of resources.

Contrast-enhanced MRI for breast cancer screening

Multiple studies in the first decade of the 21^st century have established contrast-enhanced breast MRI as a screening modality for women with a hereditary or familial increased risk for the development of breast cancer. In recent studies, in women with various risk profiles, the sensitivity ranges between 81% and 100%, which is approximately twice as high as the sensitivity of mammography. The specificity increases in follow-up rounds to around 97%, with positive predictive values for biopsy in the same range as for mammography. MRI preferentially detects the more aggressive/invasive types of breast cancer, but has a higher sensitivity than mammography for any type of cancer. This performance implies that in women screened with breast MRI, all other examinations must be regarded as supplemental. Mammography may yield ~5% additional cancers, mostly ductal carcinoma in situ, while slightly decreasing specificity and increasing the costs. Ultrasound has no supplemental value when MRI is used. Evidence is mounting that in other groups of women the performance of MRI is likewise superior to more conventional screening techniques. Particularly in women with a personal history of breast cancer, the gain seems to be high, but also in women with a biopsy history of lobular carcinoma in situ and even women at average risk, similar results are reported. Initial outcome studies show that breast MRI detects cancer earlier, which induces a stage-shift increasing the survival benefit of screening. Cost-effectiveness is still an issue, particularly for women at lower risk. Since costs of the MRI scan itself are a driving factor, efforts to reduce these costs are essential. The use of abbreviated MRI protocols may enable more widespread use of breast MRI for screening. Level of Evidence: 1 Technical Efficacy: Stage 5 J. Magn. Reson. Imaging 2019;50:377-390.

Cost-effectiveness and comparative effectiveness of cancer risk management strategies in BRCA1/2 mutation carriers: a systematic review

PURPOSE

To review the evidence for the effectiveness and cost-effectiveness of cancer risk management interventions for BRCA carriers.

METHODS

Comparative effectiveness and cost-effectiveness analyses were identified by searching scientific and health economic databases. Eligible studies modeled the impact of a cancer risk management intervention in BRCA carriers on life expectancy (LE), cancer incidence, or quality-adjusted life years (QALYs), with or without costs.

RESULTS

Twenty-six economic evaluations and eight comparative effectiveness analyses were included. Combined risk-reducing salpingo-oophorectomy and prophylactic mastectomy resulted in the greatest LE and was cost-effective in most analyses. Despite leading to increased LE and QALYs, combined mammography and breast magnetic resonance imaging (MRI) was less likely to be cost-effective than either mammography or MRI alone, particularly for women over 50 and BRCA2 carriers. Variation in patient compliance to risk management interventions was incorporated in 11/34 studies with the remaining analyses assuming 100% adherence.

CONCLUSION

Prophylactic surgery and intensive breast screening are effective and cost-effective in models of BRCA carrier risk management. Findings were based predominantly on assuming perfect adherence to recommendations without assessment of the health-care resource use and costs related to engaging patients and maximizing compliance, meaning the real-world impact on clinical outcomes and resource use remains unclear.

Simulation modeling for stratified breast cancer screening - a systematic review of cost and quality of life assumptions

BACKGROUND

The economic evaluation of stratified breast cancer screening gains momentum, but produces also very diverse results. Systematic reviews so far focused on modeling techniques and epidemiologic assumptions. However, cost and utility parameters received only little attention. This systematic review assesses simulation models for stratified breast cancer screening based on their cost and utility parameters in each phase of breast cancer screening and care.

METHODS

A literature review was conducted to compare economic evaluations with simulation models of personalized breast cancer screening. Study quality was assessed using reporting guidelines. Cost and utility inputs were extracted, standardized and structured using a care delivery framework. Studies were then clustered according to their study aim and parameters were compared within the clusters.

RESULTS

Eighteen studies were identified within three study clusters. Reporting quality was very diverse in all three clusters. Only two studies in cluster 1, four studies in cluster 2 and one study in cluster 3 scored high in the quality appraisal. In addition to the quality appraisal, this review assessed if the simulation models were consistent in integrating all relevant phases of care, if utility parameters were consistent and methodological sound and if cost were compatible and consistent in the actual parameters used for screening, diagnostic work up and treatment. Of 18 studies, only three studies did not show signs of potential bias.

CONCLUSION

This systematic review shows that a closer look into the cost and utility parameter can help to identify potential bias. Future simulation models should focus on integrating all relevant phases of care, using methodologically sound utility parameters and avoiding inconsistent cost parameters.

Estimating personalized diagnostic rules depending on individualized characteristics

There is an increasing demand for personalization of disease screening based on assessment of patient risk and other characteristics. For example, in breast cancer screening, advanced imaging technologies have made it possible to move away from 'one-size-fits-all' screening guidelines to targeted risk-based screening for those who are in need. Because diagnostic performance of various imaging modalities may vary across subjects, applying the most accurate modality to the patients who would benefit the most requires personalized strategy. To address these needs, we propose novel machine learning methods to estimate personalized diagnostic rules for medical screening or diagnosis by maximizing a weighted combination of sensitivity and specificity across subgroups of subjects. We first develop methods that can be applied when competing modalities or screening strategies that are observed on the same subject (paired design). Next, we present methods for studies where not all subjects receive both modalities (unpaired design). We study theoretical properties including consistency and risk bound of the personalized diagnostic rules and conduct simulation studies to examine performance of the proposed methods. Lastly, we analyze data collected from a brain imaging study of Parkinson's disease using positron emission tomography and diffusion tensor imaging with paired and unpaired designs. Our results show that in some cases, a personalized modality assignment is estimated to improve empirical area under the receiver operating curve compared with a 'one-size-fits-all' assignment strategy. Copyright © 2016 John Wiley & Sons, Ltd.

Identification et prise en charge des femmes ayant des antécédents familiaux de cancer du sein

Objectif

Résumer les meilleures données portant sur les stratégies d’identification et de prise en charge des femmes qui présentent des antécédents familiaux de cancer du sein.

Sources d’information

Une recherche a été effectuée sur PubMed à l’aide des mots-clés anglais suivants : breast cancer, guidelines, risk, family history, management et magnetic resonance imaging screening, entre 2000 et 2016. La plupart des données sont de niveau II.

Message principal

Une bonne anamnèse familiale est essentielle lors de l’évaluation du risque de cancer du sein afin d’identifier les femmes qui sont candidates à une recommandation en counseling génétique pour un éventuel test génétique. On peut sauver des vies en offrant aux femmes porteuses d’une mutation au gène BRCA des interventions chirurgicales de réduction des risques (mastectomie bilatérale prophylactique, salpingo-ovariectomie bilatérale). Il faut encourager toutes les femmes qui présentent des antécédents familiaux de cancer du sein à demeurer actives et à limiter leur consommation d’alcool à moins de 1 verre par jour; certaines femmes sont admissibles à la chimioprévention. Il faut offrir aux femmes dont le risque à vie de cancer du sein est de 20 à 25 % ou plus un dépistage poussé par imagerie par résonance magnétique en plus d’une mammographie.

Conclusion

Une vie saine et la chimioprévention (chez les candidates) pourraient réduire l’incidence du cancer du sein; le dépistage poussé pourrait entraîner une détection plus précoce. Le fait d’aiguiller des femmes porteuses d’une mutation au BRCA vers la chirurgie de réduction des risques sauve des vies.

Identification and management of women with a family history of breast cancer: Practical guide for clinicians

OBJECTIVE

To summarize the best evidence on strategies to identify and manage women with a family history of breast cancer.

SOURCES OF INFORMATION

A PubMed search was conducted using the search terms breast cancer, guidelines, risk, family history, management, and magnetic resonance imaging screening from 2000 to 2016. Most evidence is level II.

MAIN MESSAGE

Taking a good family history is essential when assessing breast cancer risk in order to identify women suitable for referral to a genetic counselor for possible genetic testing. Offering risk-reducing surgery (bilateral prophylactic mastectomy, bilateral salpingo-oophorectomy) to women with BRCA genetic mutations can save lives. All women with a family history of breast cancer should be encouraged to stay active and limit alcohol intake to less than 1 drink per day; some will qualify for chemoprevention. Women with a 20% to 25% or greater lifetime risk of breast cancer should be offered enhanced screening with annual magnetic resonance imaging in addition to mammography.

CONCLUSION

Healthy living and chemoprevention (for suitable women) could reduce breast cancer incidence; enhanced screening could result in earlier detection. Referring women who carry BRCA mutations for risk-reducing surgery will save lives.

25 Years of Contrast-Enhanced MRI: Developments, Current Challenges and Future Perspectives

In 1988, the first contrast agent specifically designed for magnetic resonance imaging (MRI), gadopentetate dimeglumine (Magnevist(®)), became available for clinical use. Since then, a plethora of studies have investigated the potential of MRI contrast agents for diagnostic imaging across the body, including the central nervous system, heart and circulation, breast, lungs, the gastrointestinal, genitourinary, musculoskeletal and lymphatic systems, and even the skin. Today, after 25 years of contrast-enhanced (CE-) MRI in clinical practice, the utility of this diagnostic imaging modality has expanded beyond initial expectations to become an essential tool for disease diagnosis and management worldwide. CE-MRI continues to evolve, with new techniques, advanced technologies, and novel contrast agents bringing exciting opportunities for more sensitive, targeted imaging and improved patient management, along with associated clinical challenges. This review aims to provide an overview on the history of MRI and contrast media development, to highlight certain key advances in the clinical development of CE-MRI, to outline current technical trends and clinical challenges, and to suggest some important future perspectives.

FUNDING

Bayer HealthCare.

Economic Evaluation Alongside a Clinical Trial of Telephone Versus In-Person Genetic Counseling for BRCA1/2 Mutations in Geographically Underserved Areas

PURPOSE

BRCA1/2 counseling and mutation testing is recommended for high-risk women, but geographic barriers exist, and no data on the costs and yields of diverse delivery approaches are available.

METHODS

We performed an economic evaluation with a randomized clinical trial comparing telephone versus in-person counseling at 14 locations (nine geographically remote). Costs included fixed overhead, variable staff, and patient time costs; research costs were excluded. Outcomes included average per-person costs for pretest counseling; mutations detected; and overall counseling, testing, and disclosure. Sensitivity analyses were performed to assess the impact of uncertainty.

RESULTS

In-person counseling was more costly per person counseled than was telephone counseling ($270 [range, $180 to $400] v $120 [range, $80 to $200], respectively). Counselors averaged 285 miles round-trip to deliver in-person counseling to the participants (three participants per session). There were no differences by arm in mutation detection rates (approximately 10%); therefore, telephone counseling was less costly per positive mutation detected than was in-person counseling ($37,160 [range, $36,080 to$38,920] v $40,330 [range, $38,010 to $43,870]). In-person counseling would only be less costly than telephone counseling if the most favorable assumptions were applied to in personc ounseling and the least favorable assumptions were applied to telephone counseling.

CONCLUSION

In geographically underserved areas, telephone counseling is less costly than in-person counseling.

Screening Breast MRI in Patients Previously Treated for Breast Cancer: Diagnostic Yield for Cancer and Abnormal Interpretation Rate

RATIONALE AND OBJECTIVES

To determine the cancer detection rate and abnormal interpretation rate of screening breast magnetic resonance imaging (MRI) in previously treated breast cancer patients.

MATERIALS AND METHODS

Institutional review board-approved retrospective review of the breast MRI database from 2009 to 2011 identified a total of 3297 screening examinations. After excluding genetic mutation carriers, untested first-degree relatives of known mutation carriers, and patients with a history of chest irradiation, there were 1194 (36.2%) examinations in 691 patients previously treated for breast cancer. MRI reports were reviewed to determine MRI findings and breast imaging reporting and data system (BI-RADS) assessments. The longitudinal medical record was reviewed to determine patient demographics and outcomes of imaging surveillance and biopsy.

RESULTS

Mean patient age at initial cancer diagnosis was 46.1 years, and mean patient age during the study interval was 52 years. Cancer detection rate was 10 per 1000 (1%; 95% confidence interval [CI], 0.5%-1.8%]; 12 of 1194 examinations). Overall 10.7% (128 of 1194) of examinations received an abnormal interpretation, including 5.4% (65 of 1194) BI-RADS 4 or 5 and 5.3% (63 of 1194) BI-RADS 3 assessments with a 9.4% positive predictive value (PPV1; 12 of 128 examinations) and a 17.9% PPV3 (12 malignancies per 67 biopsies).

CONCLUSIONS

Screening breast MRI in women previously treated for breast cancer detected cancer in 1.0% of examinations, with a 10.7% abnormal interpretation rate, and a PPV for malignancy of 17.9%.

Abbreviated screening protocol for breast MRI: a feasibility study

RATIONALE AND OBJECTIVES

To compare the performance of two shortened breast magnetic resonance imaging (MRI) protocols to a standard MRI protocol for breast cancer screening.

MATERIALS AND METHODS

In this Health Insurance Portability and Accountability Act compliant, institutional review board-approved pilot study, three fellowship-trained breast imagers evaluated 48 breast MRIs (24 normal, 12 benign, and 12 malignant) selected from a high-risk screening population. MRIs were presented in three viewing protocols, and a final Breast Imaging-Reporting and Data System assessment was recorded for each case. The first shortened protocol (abbreviated 1) included only fat-saturated precontrast T2-weighted, precontrast T1-weighted, and first pass T1-weighted postcontrast sequences. The second shortened protocol (abbreviated 2) included the abbreviated 1 protocol plus the second pass T1-weighted postcontrast sequence. The third protocol (full), reviewed after a 1-month waiting period, included a nonfat-saturated T1-weighted sequence, fat-saturated T2-weighted, precontrast T1-weighted, and three or four dynamic postcontrast sequences. Interpretation times were recorded for the abbreviated 1 and full protocols. Sensitivity and specificity were compared via a chi-squared analysis. This pilot study was designed to detect a 10% difference in sensitivity with a power of 0.8.

RESULTS

There was no significant difference in sensitivity between the abbreviated 1 (86%; P = .22) or abbreviated 2 (89%; P = .38) protocols and the full protocol (95%). There was no significant difference in specificity between the abbreviated 1 (52%; P = 1) or abbreviated 2 (45%; P = .34) protocols and the full protocol (52%). The abbreviated 1 and full protocol interpretation times were similar (2.98 vs. 3.56 minutes).

CONCLUSIONS

In this pilot study, reader performance comparing two shortened breast MRI protocols to a standard protocol in a screening cohort were similar, suggesting that a shortened breast MRI protocol may be clinically useful, warranting further investigation.

Clinical management of women at high risk of breast cancer

PURPOSE OF REVIEW

This article reviews the evidence that underpins breast cancer screening and prevention strategies for women at high risk of the disease, with a particular focus on evidence published in the last 18 months. The review is timely because the US National Comprehensive Cancer Network, the UK National Institute for Health and Care Excellence and the American Society of Clinical Oncology have recently updated relevant guidelines that inform practice.

RECENT FINDINGS

In the recently published literature, there have been several important findings. A meta-analysis of randomized trials of selective oestrogen receptor modulators (SERMs), along with the first results from the International Breast Cancer Intervention Study II trial, further support the use of SERMs and aromatase inhibitors in the primary prevention of breast cancer. A large observational study has provided evidence that the SERM tamoxifen may be efficacious for breast cancer prevention in women who carry mutations in the breast cancer predisposition genes, BRCA1 and BRCA2. Several observational studies have suggested that contralateral risk-reducing mastectomy, following a diagnosis of breast cancer, may reduce mortality.

SUMMARY

Evidence regarding the optimal management of women at high risk of breast cancer continues to evolve and needs to be rapidly implemented into clinical practice.

Cost-effectiveness of alternative strategies for integrating MRI into breast cancer screening for women at high risk

BACKGROUND

Magnetic resonance imaging (MRI) is recommended for women at high risk for breast cancer. We evaluated the cost-effectiveness of alternative screening strategies involving MRI.

METHODS

Using a microsimulation model, we generated life histories under different risk profiles, and assessed the impact of screening on quality-adjusted life-years, and lifetime costs, both discounted at 3%. We compared 12 screening strategies combining annual or biennial MRI with mammography and clinical breast examination (CBE) in intervals of 0.5, 1, or 2 years vs without, and reported incremental cost-effectiveness ratios (ICERs).

RESULTS

Based on an ICER threshold of $100,000/QALY, the most cost-effective strategy for women at 25% lifetime risk was to stagger MRI and mammography plus CBE every year from age 30 to 74, yielding ICER $58,400 (compared to biennial MRI alone). At 50% lifetime risk and with 70% reduction in MRI cost, the recommended strategy was to stagger MRI and mammography plus CBE every 6 months (ICER=$84,400). At 75% lifetime risk, the recommended strategy is biennial MRI combined with mammography plus CBE every 6 months (ICER=$62,800).

CONCLUSIONS

The high costs of MRI and its lower specificity are limiting factors for annual screening schedule of MRI, except for women at sufficiently high risk.

A MDP model for breast and ovarian cancer intervention strategies for BRCA1/2 mutation carriers

PURPOSE

Women with BRCA1/2 mutations have higher risk for breast and ovarian cancers. Available intervention actions include prophylactic surgeries and breast screening, which vary significantly in cost, cancer prevention, and in resulting death from other causes. We present a model designed to yield optimal intervention strategies for mutation carriers between the ages of 30 and 65 and any prior intervention history.

METHODS

A Markov decision process (MDP) model is developed that considers yearly state transitions for the mutation carriers and state dependent intervention actions. State is defined as a vector comprising mutation type, health states, prior intervention actions, and age. A discounted value iteration algorithm is used to obtain optimal strategies from the MDP model using both cost and quality-adjusted life years (QALYs) as rewards.

RESULTS

The results from MDP model show that for 30-year-old women with BRCA1 mutation and no prior intervention history, the cost-optimal strategy is a combination of prophylactic mastectomy (PM) and prophylactic oophorectomy (PO) at age 30 with no screening afterwards. Whereas, the QALYs-optimal strategy suggests PO at age 30 and PM at age 50 with screening afterwards. For BRCA2 mutation carriers at age 30, the cost-optimal strategy is PO at age 30, PM at age 40, and yearly screening only after age 56. Corresponding QALYs-optimal strategy is PM at age 40 with screening. Strategies for all other ages (31 to 65) are obtained and presented. It is also demonstrated that the cost-optimal strategies offer near maximum survival rate and near minimum cancer incidence rates by age 70, when compared to other ad hoc strategies.

Monitoring mammary tumor progression and effect of tamoxifen treatment in MMTV-PymT using MRI and magnetic resonance spectroscopy with hyperpolarized [1-13C]pyruvate

PURPOSE

To use dynamic magnetic resonance spectroscopy (MRS) of hyperpolarized (13)C-pyruvate to follow the progress over time in vivo of breast cancer metabolism in the MMTV-PymT model, and to follow the response to the anti-estrogen drug tamoxifen.

METHODS

Tumor growth was monitored by anatomical MRI by measuring tumor volumes. Dynamic MRS of hyperpolarized (13)C was used to measure an "apparent" pyruvate-to-lactate rate constant (kp) of lactate dehydrogenase (LDH) in vivo. Further, ex vivo pathology and in vitro LDH initial reaction velocity were evaluated.

RESULTS

Tamoxifen significantly halted the tumor growth measured as tumor volume by MRI. In the untreated animals, kp correlated with tumor growth. The kP was somewhat but not significantly lower in the treated group. Studies in vitro confirmed the effects of tamoxifen on tumor growth, and here the LDH reaction velocity was reduced significantly in the treated group.

CONCLUSION

These hyperpolarized (13)C MRS findings indicate that tumor metabolic changes affects kP. The measured kp did not relate to treatment response to the same extent as did tumor growth, histological evaluation, and in vitro determination of LDH activity.