Imaging bone metastases in breast cancer: evidence on comparative test accuracy

Radiologic patterns of distant organ metastasis in advanced breast cancer patients: Prospective review of computed tomography images

BACKGROUND

Breast cancer (BC) metastases to the abdomen and pelvis affect the liver, mesentery, retroperitoneum, peritoneum, bladder, kidney, ovary, and uterus. The study documented the radiological pattern and features of the chest, bone, abdominal and pelvic (AP) metastases among advanced BC patients.

AIM

The aim is to document the radiological pattern and features of breast cancer metastasis in the chest, abdomen, pelvis and bones.

MATERIALS AND RESULTS

Chest, abdominal, and pelvic computed tomography scan images of 36 patients with advanced BC were collated from Cape Coast Teaching Hospital and RAAJ Diagnostics. The images were prospectively assessed for metastasis to the organs of the chest, AP soft tissues, and bones. Radiologic features of metastasis of the lungs, liver, lymph nodes (LNs), and bones were documented. Patients' demographics, clinical data, and histopathology reports were also collected. The data were captured using UVOSYO and exported to Microsoft Excel templates. The data obtained were descriptively analyzed. Only 2.8% of BCs exhibited metaplastic BC, whereas 97.2% had invasive ductal BC. Triple-negative cases were 55.6%. Of 36 patients, 31 (86.1%), 21 (58.3%), and 14(38.8%) were diagnosed of chest, AP, and bone tissues metastasis, respectively. LN involvement was reported in 26 (72.2%) patients. Majority, 21 (58.3%) were diagnosed of multiple sites metastasis with 15 (41.7%) showing single site. Lungs (77.4%, 24/31) and liver (47.6%, 10/21) were the most affected distant organs. Most bone metastases were lytic lesions (92.9%, 13/14) with the vertebrae (85.7%, 12/14) been the most affected.

CONCLUSION

According to the study, advanced BC patients have a higher-than-average radiologic incidence of lung, liver, bone, and LN metastases.

The current role of nuclear medicine in breast cancer

Breast cancer is the most common cancer in females worldwide. Nuclear medicine plays an important role in patient management, not only in initial staging, but also during follow-up. Radiopharmaceuticals to study breast cancer have been used for over 50 years, and several of these are still used in clinical practice, according to the most recent guideline recommendations.In this critical review, an overview of nuclear medicine procedures used during the last decades is presented. Current clinical indications of each of the conventional nuclear medicine and PET/CT examinations are the focus of this review, and are objectively provided. Radionuclide therapies are also referred, mainly summarising the methods to palliate metastatic bone pain. Finally, recent developments and future perspectives in the field of nuclear medicine are discussed. In this context, the promising potential of new radiopharmaceuticals not only for diagnosis, but also for therapy, and the use of quantitative imaging features as potential biomarkers, are addressed.Despite the long way nuclear medicine has gone through, it looks like it will continue to benefit clinical practice, paving the way to improve healthcare provided to patients with breast cancer.

Early diagnosis of breast cancer lung metastasis by nanoprobe-based luminescence imaging of the pre-metastatic niche

Background

Early detection of breast cancer lung metastasis remains highly challenging, due to few metastatic cancer cells at an early stage. Herein we propose a new strategy for early diagnosis of lung metastasis of breast cancer by luminescence imaging of pulmonary neutrophil infiltration via self-illuminating nanoprobes.

Methods

Luminescent nanoparticles (LAD NPs) were engineered using a biocompatible, neutrophil-responsive self-illuminating cyclodextrin material and an aggregation-induced emission agent. The chemiluminescence resonance energy transfer (CRET) effect and luminescence properties of LAD NPs were fully characterized. Using mouse peritoneal neutrophils, in vitro luminescence properties of LAD NPs were thoroughly examined. In vivo luminescence imaging and correlation analyses were performed in mice inoculated with 4T1 cancer cells. Moreover, an active targeting nanoprobe was developed by surface decoration of LAD NPs with a neutrophil-targeting peptide, which was also systemically evaluated by in vitro and in vivo studies.

Results

LAD NPs can generate long-wavelength and persistent luminescence due to the CRET effect. In a mouse model of 4T1 breast cancer lung metastasis, we found desirable correlation between neutrophils and tumor cells in the lungs, demonstrating the effectiveness of early imaging of the pre-metastatic niche by the newly developed LAD NPs. The active targeting nanoprobe showed further enhanced luminescence imaging capability for early detection of pulmonary metastasis. Notably, the targeting nanoprobe-based luminescence imaging strategy remarkably outperformed PET/CT imaging modalities in the examined mouse model. Also, preliminary tests demonstrated good safety of LAD NPs.

Conclusions

The neutrophil-targeting imaging strategy based on newly developed luminescence nanoparticles can serve as a promising modality for early diagnosis of lung metastasis of breast cancers.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s12951-022-01346-4.

Bone Metastases Are Measurable: The Role of Whole-Body MRI and Positron Emission Tomography

Metastatic tumor deposits in bone marrow elicit differential bone responses that vary with the type of malignancy. This results in either sclerotic, lytic, or mixed bone lesions, which can change in morphology due to treatment effects and/or secondary bone remodeling. Hence, morphological imaging is regarded unsuitable for response assessment of bone metastases and in the current Response Evaluation Criteria In Solid Tumors 1.1 (RECIST1.1) guideline bone metastases are deemed unmeasurable. Nevertheless, the advent of functional and molecular imaging modalities such as whole-body magnetic resonance imaging (WB-MRI) and positron emission tomography (PET) has improved the ability for follow-up of bone metastases, regardless of their morphology. Both these modalities not only have improved sensitivity for visual detection of bone lesions, but also allow for objective measurements of bone lesion characteristics. WB-MRI provides a global assessment of skeletal metastases and for a one-step "all-organ" approach of metastatic disease. Novel MRI techniques include diffusion-weighted imaging (DWI) targeting highly cellular lesions, dynamic contrast-enhanced MRI (DCE-MRI) for quantitative assessment of bone lesion vascularization, and multiparametric MRI (mpMRI) combining anatomical and functional sequences. Recommendations for a homogenization of MRI image acquisitions and generalizable response criteria have been developed. For PET, many metabolic and molecular radiotracers are available, some targeting tumor characteristics not confined to cancer type (e.g. 18F-FDG) while other targeted radiotracers target specific molecular characteristics, such as prostate specific membrane antigen (PSMA) ligands for prostate cancer. Supporting data on quantitative PET analysis regarding repeatability, reproducibility, and harmonization of PET/CT system performance is available. Bone metastases detected on PET and MRI can be quantitatively assessed using validated methodologies, both on a whole-body and individual lesion basis. Both have the advantage of covering not only bone lesions but visceral and nodal lesions as well. Hybrid imaging, combining PET with MRI, may provide complementary parameters on the morphologic, functional, metabolic and molecular level of bone metastases in one examination. For clinical implementation of measuring bone metastases in response assessment using WB-MRI and PET, current RECIST1.1 guidelines need to be adapted. This review summarizes available data and insights into imaging of bone metastases using MRI and PET.

Gastrointestinal stromal tumor with multisegmental spinal metastases as first presentation: A case report and review of the literature

BACKGROUND

Gastrointestinal stromal tumor (GIST) usually originates in the stomach, followed by the small intestine, rectum, and other parts of the gastrointestinal tract. The most common sites of metastasis are the liver and peritoneum, whereas spinal metastases from GIST are extremely rare.

CASE SUMMARY

We found a case of GIST with the first presentation of multilevel spinal metastases involving the thoracic and lumbar vertebrae. A 61-year-old Chinese man presented to our clinic because of pain in his lower back and hip for 10 d without cause. Subsequently, computed tomography (CT) and magnetic resonance imaging (MRI) revealed abnormal signals in the vertebral appendages of T12 and L4 accompanied by spinal canal stenosis, which was considered as tumor metastasis. As there were no metastases to vital organs, posterior thoracic and lumbar spinal decompression + adnexal mass resection + pedicle internal fixation was adopted to achieve local cure and prevent nerve compression. The results of histopathological studies were consistent with the metastasis of GIST. No local recurrence or new metastases were found at the 6-mo follow-up at the surgical site. The patient has no neurological symptoms at present. It is worth mentioning that a rectal mass was found and surgically removed 1 mo after the patient was discharged from hospital, and the pathological diagnosis of the mass was GIST.

CONCLUSION

By reviewing 26 previously reported cases of spinal metastasis in GIST, it was found that spinal metastasis of GIST has become more common in recent years, so the possibility of early spinal metastasis should be recognized. CT and MRI are of great value in the diagnosis of spinal metastatic tumors, and pathological biopsy is the gold standard for the diagnosis of metastatic tumors. It is safe and feasible to treat isolated spinal metastasis in GIST by excising metastatic masses, decompressing the spinal canal, and stabilizing the spine.

Imaging diagnosis of metastatic breast cancer

Numerous imaging modalities may be used for the staging of women with advanced breast cancer. Although bone scintigraphy and multiplanar-CT are the most frequently used tests, others including PET, MRI and hybrid scans are also utilised, with no specific recommendations of which test should be preferentially used. We review the evidence behind the imaging modalities that characterise metastases in breast cancer and to update the evidence on comparative imaging accuracy.

Nuclear Medicine Imaging Techniques for Detection of Skeletal Metastases in Breast Cancer

Bone is the most common site of metastases from advanced breast cancer. Whole-body bone scintigraphy has been most frequently used in the process of managing cancer patients; its advantage is that it provides rapid whole-body imaging for screening of osteoblastic or sclerotic/mixed bone metastases at reasonable cost. Recent advanced techniques, such as single-photon emission computed tomography (SPECT)/CT, quantitative analysis, and bone scan index, contribute to better understanding of the disease state. More recent advances in machines and PET drugs improve the staging of the skeleton with higher sensitivity and specificity.

Whole-Body Magnetic Resonance Imaging in the Oncology Setting: An Overview and Update on Recent Advances

Whole-body magnetic resonance imaging is becoming an important tool in oncology as a nonirradiating imaging technique since recent technological advances allowed the incorporation of high-quality imaging in an adequate time. Moreover, the noninjection of radioisotope/intravenous contrast, low cost compared with traditional nuclear medicine techniques, and fast acquisition times are another distinct feature. Thus, the purpose of this article is to review the whole-body magnetic resonance imaging protocol and its main applications in the oncology setting.

US Food and Drug Administration Pooled Analysis to Assess the Impact of Bone-Only Metastatic Breast Cancer on Clinical Trial Outcomes and Radiographic Assessments

Purpose The outcome and proportion of patients with bone-only (BO) metastatic breast cancer (MBC) has not been well described. We sought to describe the differential outcomes of patients with BO MBC in clinical trials and explore whether there was a discrepancy in radiographic reads between investigator and blinded independent central review. Methods We pooled and analyzed data on 10,521 patients from 13 prospective trials submitted for MBC treatment in initial or supplemental New Drug or Biologics License Applications from 2005. Three subsets were evaluated: BO, bone with other metastases (BWO), and no bone metastases (NBM). Early discordance rate and late discordance rate were calculated from 3,733 and 2,813 patients subject to a blinded independent central review, respectively. Results Bone metastases were identified in 49% (range: 42% to 73%) of patients across trials. BO disease was present in 12.5% (range: 4% to 26%), dependent on subtype. Investigator-assessed progression-free survival (PFS) and overall survival (OS) for the pooled trials demonstrated improved outcomes for the BO subgroup compared with other subgroups (BO v BWO PFS hazard ratio [HR], 0.64; 95% CI, 0.591 to 0.696; BO v NBM PFS HR, 0.70; 95% CI, 0.65 to 0.76; BO v BWO OS HR, 0.56; 95% CI, 0.50 to 0.61; BO v NBM OS HR, 0.68; 95% CI, 0.61 to 0.76). The BO subgroup has a higher early discordance rate and lower late discordance rate than the BWO and NBM subgroups. Conclusion To our knowledge, this review is the largest analysis to date of the BO subgroup of MBC and suggests this subgroup may have a distinct natural history. There also seems to be a difference in how the local investigators assessed progression events in the BO subgroup when compared with the other two groups.

Incidence, risk factors and prognostic characteristics of bone metastases and skeletal-related events (SREs) in breast cancer patients: A systematic review of the real world data

Purpose

The aim was to systematically extrapolate the occurrence, risk factors, prognostic characteristics, management and outcome of bone metastases (BM) and skeletal related events (SREs) of breast cancer survivors in the real world clinical setting.

Methods

A systematic literature search of PubMed, Web of Science, EMBASE OvidSP and EBSCO Academic Search Complete was conducted. Published prospective and retrospective papers investigating BM and SREs in breast cancer patients in non-trial settings were identified and systematically reviewed.

Results

Twenty-four studies met the inclusion criteria. Incidences of BM based on new diagnosis, length of BM-free interval (BMFI) and number and sites of BM were detected by 17 of 24 studies. Seven studies included in the review were subjected to analyses of risk factors for BM. Developments of SREs regarding the occurrence ratio of total and specific SREs, SERs-free interval (SREFI) and the first-line therapy for SREs were observed in 16 of 24 studies. Out of 5 studies, we extracted uni- and multivariate analysis of risk factor for SREs and out of 16 studies - predictors for survival in breast cancer patients with BM.

Conclusions

BM and SREs are common problems in non-trial breast cancer populations. Patient demographics, clinical stage, tumor pathological type, molecular receptors status are significantly risk factors for incidence of BM, SREs and the survival. The unique characteristics of BM and SREs in breast cancer patients should be taken into account in future randomized controlled trials, as to optimize individual treatment options and assure a maximally long good quality of life.

Planar Bone Scan Versus Computerized Tomography in Staging Locally Advanced Breast Cancer in Asymptomatic Patients: Does Bone Scan Change Patient Management Over Computerized Tomography?

AIM

The Royal College of Radiologists guidelines from 2013 recommend that contrast-enhanced computerized tomography of chest, abdomen and pelvis (CT TAP) for breast cancer patients with suspected metastasis could obviate the need for bone scan in asymptomatic patients. The purpose of this study was to perform a head-to-head comparison of bone scan and CT scan in locally advanced breast cancer patients. The aim of this study was to evaluate the utility of planar bone scan in changing the stage or management of locally advanced breast cancer patients.

METHODS

Between June 2006 and January 2016, 156 breast cancer patients had staging investigations (either CT and bone scans, bone scans only, or CT only). All images and reports on picture archiving and communication system were evaluated retrospectively.

RESULTS

One hundred five of 156 patients had both CT TAP and bone scan within 10 days of each other. Of the total of 105 patients, 33 (31.4%) had concordant normal results on CT TAP and bone scan. There were 18/105 (17.1%) patients with extraosseous metastasis on CT with negative or inconclusive bone scan. Bone scans diagnosed peripheral osseous metastasis in 5/105 (4.7%), which were either skull or extremity metastasis outside CT TAP field of view. All of these 5 patients had other metastatic lesions within axial skeleton or soft tissues on CT and led to no change in patient management.

CONCLUSIONS

Our findings suggest routine use of bone scan in asymptomatic patients with locally advanced breast cancer did not change patient management.

PET Tracer 18F-Fluciclovine Can Detect Histologically Proven Bone Metastatic Lesions: A Preclinical Study in Rat Osteolytic and Osteoblastic Bone Metastasis Models

¹⁸F-Fluciclovine (trans-1-amino-3-¹⁸F-fluorocyclobutanecarboxylic acid; anti-¹⁸F-FACBC) is a positron emission tomography (PET) tracer for diagnosing cancers (e.g., prostate and breast cancer). The most frequent metastatic organ of these cancers is bone. Fluciclovine-PET can visualize bony lesions in clinical practice; however, such lesions have not been described histologically. Methods: We investigated the potential of ¹⁴C-fluciclovine in aiding the visualization of osteolytic and osteoblastic bone metastases (with histological analyses), compared with ³H-2-deoxy-2-fluoro-D-glucose (³H-FDG), ³H-choline chloride (³H-choline), and ^99mTc-hydroxymethylene diphosphonate (^99mTc-HMDP) by using triple-tracer autoradiography in rat breast cancer osteolytic (on day 12 ± 1 postinjection of MRMT-1) and prostate cancer osteoblastic (on day 20 ± 3 postinjection of AT6.1) metastatic models. Results: The distribution patterns of ¹⁴C-fluciclovine, ³H-FDG, and ³H-choline, but not ^99mTc-HMDP, were similar in both models, and the lesions where these tracers accumulated were, histologically, typical osteolytic and osteoblastic lesions. ^99mTc-HMDP accumulated mostly in osteoblastic lesions. ¹⁴C-fluciclovine could visualize the osteolytic lesions as early as day 6 postinjection of MRMT-1. However, differential distributions in ¹⁴C-fluciclovine and ³H-FDG existed, based on histological differences: low ¹⁴C-fluciclovine and high ³H-FDG accumulation in osteolytic lesions with inflammation. In the osteoblastic metastatic model, visualization of osteoblastic lesions with ¹⁴C-fluciclovine was not clear, yet clearer than with ³H-FDG. Although half of the osteoblastic lesions with ¹⁴C-fluciclovine accumulation showed negligible ³H-choline accumulation in comparison, they were histologically similar to lesions with marked ¹⁴C-fluciclovine and ³H-choline accumulation. Conclusion: These results suggest that fluciclovine-PET can visualize true osteolytic and osteoblastic bone metastatic lesions.

National consensus in China on diagnosis and treatment of patients with advanced breast cancer

The recently available guidelines on the management of advanced breast cancer (ABC) organized by Chinese Anti-Cancer Association, Committee of Breast Cancer Society (CACA-CBCS) do not elucidate ABC in details. To instruct clinicians in treatment of ABC, a Chinese expert consensus meeting on diagnosis and treatment of ABC was held in June 2014 and a consensus is developed. The following consensus provides the level of evidence and supporting documents for each recommendation, and introduces research topics to be urgently addressed. Notably, the consensus on diagnosis and treatment of ABC in China is developed to be applied nationwide. In different areas, multidisciplinary treatment (MDT) tailored to the each patient and the disease itself should be applied based on the basic principles of modern oncology.

Comparison of 18F-FDG PET/CT for Systemic Staging of Newly Diagnosed Invasive Lobular Carcinoma Versus Invasive Ductal Carcinoma

Although guidelines such as those of the National Comprehensive Cancer Network consider (18)F-FDG PET/CT for systemic staging of newly diagnosed stage III breast cancer patients, factors in addition to stage may influence the utility of PET/CT. Because invasive lobular carcinoma (ILC) is less conspicuous than invasive ductal carcinoma (IDC) on (18)F-FDG PET, we hypothesized that tumor histology may be one such factor. We evaluated PET/CT systemic staging of patients newly diagnosed with ILC compared with IDC.

METHODS

In this Institutional Review Board-approved retrospective study, our Hospital Information System was screened for ILC patients who underwent PET/CT in 2006-2013 before systemic or radiation therapy. Initial stage was determined from examination, mammography, ultrasound, MR, or surgery. PET/CT was performed to identify unsuspected distant metastases. A sequential cohort of stage III IDC patients was evaluated for comparison. Upstaging rates were compared using the Pearson χ(2) test.

RESULTS

The study criteria were fulfilled by 146 ILC patients. PET/CT revealed unsuspected distant metastases in 12 (8%): 0 of 8 with initial stage I, 2 of 50 (4%) stage II, and 10 of 88 (11%) stage III. Upstaging to IV by PET/CT was confirmed by biopsy in all cases. Three of 12 upstaged patients were upstaged only by the CT component of the PET/CT, as the metastases were not (18)F-FDG-avid. In the comparison stage III IDC cohort, 22% (20/89) of patients were upstaged to IV by PET/CT. All 20 demonstrated (18)F-FDG-avid metastases. The relative risk of PET/CT revealing unsuspected distant metastases in stage III IDC patients was 1.98 times (95% confidence interval, 0.98-3.98) that of stage III ILC patients (P = 0.049). For (18)F-FDG-avid metastases, the relative risk of PET/CT revealing unsuspected (18)F-FDG-avid distant metastases in stage III IDC patients was 2.82 times (95% confidence interval, 1.26-6.34) that of stage III ILC patients (P = 0.007).

CONCLUSION

(18)F-FDG PET/CT was more likely to reveal unsuspected distant metastases in stage III IDC patients than in stage III ILC patients. In addition, some ILC patients were upstaged by non-(18)F-FDG-avid lesions visible only on the CT images. Overall, the impact of PET/CT on systemic staging may be lower for ILC patients than for IDC patients.

The value of PET/CT with FES or FDG tracers in metastatic breast cancer: a computer simulation study in ER-positive patients

Background:

The aim of this study was to evaluate the effect on the number of performed biopsies and costs associated with implementing positron emission tomography (PET) and computed tomography (PET/CT) with 16α-[¹⁸F]fluoro-17β-oestradiol (FES) or 2-[¹⁸F]fluoro-2-deoxy-D-glucose (FDG) as an upfront imaging test for diagnosing metastatic breast cancer (MBC) in comparison with the standard work-up in oestrogen receptor-positive women with symptoms.

Methods:

A published computer simulation model was adapted and validated. Three follow-up strategies were evaluated in a simulated cohort of women with primary breast cancer over a 5-year-time horizon: (1) the standard work-up, (2) upfront FES-PET/CT and (3) upfront FDG-PET/CT. The main outcome was the number of avoided biopsies to assess MBC. The costs for all three strategies were calculated based on the number of imaging tests and biopsies. The incremental cost-effectiveness ratio (ICER) to avoid a biopsy was calculated only based on the costs of initial imaging and staging tests.

Results:

The FES-PET/CT strategy decreased the number of biopsies by 39±9%, while upfront FDG-PET/CT increased the number of biopsies by 38±15% when compared with the standard work-up. Both PET/CT strategies reduced the number of imaging tests and false positives when compared with the standard work-up. The number of false negatives decreased only in the FES-PET/CT strategy. The ICER in the FES-PET/CT strategy per avoided biopsy was 12.1±3.4 thousand Euro. In the FDG-PET/CT strategy, the costs were higher and there were no avoided biopsies as compared with the standard work-up, hence this was an inferior strategy in terms of cost effectiveness.

Conclusions:

The number of performed biopsies was lower in the FES-PET/CT strategy at an ICER of 12.1±3.4 thousand Euro per biopsy avoided, whereas the application of the FDG-PET/CT did not reduce the number of biopsies and was more expensive. Whether the FES-PET/CT strategy has additional benefits for patients in terms of therapy management has to be evaluated in clinical studies.

Comparison of CE-FDG-PET/CT with CE-FDG-PET/MR in the evaluation of osseous metastases in breast cancer patients

BACKGROUND

Despite improvements in treatments, metastatic breast cancer remains difficult to cure. Bones constitute the most common site of first-time recurrence, occurring in 40-75% of cases. Therefore, evaluation for possible osseous metastases is crucial. Technetium 99 ((99)Tc) bone scintigraphy and fluorodexossyglucose (FDG) positron emission tomography (PET)-computed tomography (PET-CT) are the most commonly used techniques to assess osseous metastasis. PET magnetic resonance (PET-MR) imaging is an innovative technique still under investigation. We compared the capability of PET-MR to that of same-day PET-CT to assess osseous metastases in patients with breast cancer.

METHODS

One hundred and nine patients with breast cancer, who underwent same-day contrast enhanced (CE)-PET-CT and CE-PET-MR, were evaluated. CE-PET-CT and CE-PET-MR studies were interpreted by consensus by a radiologist and a nuclear medicine physician. Correlations with prior imaging and follow-up studies were used as the reference standard. Binomial confidence intervals and a χ(2) test were used for categorical data, and paired t-test was used for the SUVmax data; a non-informative prior Bayesian approach was used to estimate and compare the specificities.

RESULTS

Osseous metastases affected 25 out 109 patients. Metastases were demonstrated by CE-PET-CT in 22 out of 25 patients (88%±7%), and by CE-PET-MR in 25 out of 25 patients (100%). CE-PET-CT revealed 90 osseous metastases and CE-PET-MR revealed 141 osseous metastases (P<0.001). The estimated sensitivity of CE-PET-CT and CE-PET-MR were 0.8519 and 0.9630, respectively. The estimated specificity for CE-FDG-PET-MR was 0.9884. The specificity of CE-PET-CT cannot be determined from patient-level data, because CE-PET-CT yielded a false-positive lesion in a patient who also had other, true metastases.

CONCLUSIONS

CE-PET-MR detected a higher number of osseous metastases than did same-day CE-PET-CT, and was positive for 12% of the patients deemed osseous metastasis-negative on the basis of CE-PET-CT.

Detection and Clinical Significance of Sternal Lesions on Breast MRI

The purpose of this study is to characterize sternal lesions detected on breast magnetic resonance imaging (MRI), compare MRI detection of sternal lesions with other imaging modalities (bone scan, positron emission tomography/computed tomography (PET/CT) and chest CT), and ascertain how often patient management is altered by discovery of sternal lesions. Retrospective review of 1143 breast MRIs between 2007 and 2012 identified 17 patients with sternal lesions including 15 patients with newly diagnosed breast cancer and two patients with remote history of breast cancer. Tumor size, histopathology, receptor status, nodal and distant metastasis, and images of breast MRI, and other modalities were reviewed. Sternal lesions in 9 of the 17 patients were determined to be malignant (metastasis) either by biopsy or presence of widespread metastases. Sternal lesions in 8 of the 17 were benign, confirmed by biopsy or presumed benign as not detected by other modalities. The malignant group had statistically significant larger breast cancer size (malignant: 6.4 cm; benign: 2.3 cm), a higher percentage of diffuse sternal lesions (malignant: 56%; benign: 0%), and more frequently showed rapid initial enhancing (malignant: 100%; benign: 63%) and delayed washout curves (malignant: 67%; benign: 13%). Although not statistically significant, the malignant group had a higher frequency of invasive lobular carcinoma (malignant: 44%; benign: 13%) and more lymph node involvement (malignant: 78%; benign: 50%). Breast MRI detected more sternal lesions than did bone scan, PET/CT and chest CT. Four of the 17 (24%) patients were upgraded to stage 4 due to unsuspected metastatic sternal lesions on breast MRI. In conclusion, breast MRI is more sensitive than other modalities in detecting sternal lesions. Sternal metastases occur more frequently in aggressive breast cancer and exhibit malignant-type dynamics on breast MRI. Detection of unsuspected sternal metastasis alters staging and improves patient management with more appropriate treatment.

The role of general nuclear medicine in breast cancer

The rising incidence of breast cancer worldwide has prompted many improvements to current care. Routine nuclear medicine is a major contributor to a full gamut of clinical studies such as early lesion detection and stratification; guiding, monitoring, and predicting response to therapy; and monitoring progression, recurrence or metastases. Developments in instrumentation such as the high-resolution dedicated breast device coupled with the diagnostic versatility of conventional cameras have reinserted nuclear medicine as a valuable tool in the broader clinical setting. This review outlines the role of general nuclear medicine, concluding that targeted radiopharmaceuticals and versatile instrumentation position nuclear medicine as a powerful modality for patients with breast cancer.

Evaluation of bone metastases from breast cancer by bone scintigraphy and positron emission tomography/computed tomography imaging

OBJECTIVE

The aim of this study was to compare bone scintigraphy (BS) and positron emission tomography/computed tomography (PET/CT) for the detection of bone metastases from breast cancer.

STUDY DESIGN

Twenty patients with breast cancer and bone pain were submitted to both bone scintigraphy and 18-F-fluorodeoxyglucose PET/CT imaging between July 2012 and June 2013. Scintigraphy was performed following an intravenous injection of technetium-99m-methylene diphosphonate (99mTc-MDP) around 10 days before the PET/CT scan, performed using an intravenous injection of 18-F-fluorodeoxyglucose followed by whole-body computed tomography (CT) to characterize metastases by both methods. Student's t-test for paired samples was used in the comparative data analysis, with significance at p<0.05.

RESULTS

CT identified 429 metastatic implants in the 20 patients, with scintigraphy showing 244 of these lesions (57%) and PET/CT showing 307 (72%); however, there was no statistically significant difference between the mean number of lesions detected per patient with the two imaging modalities (p=0.367).

CONCLUSION

In the present study, no difference was found between PET/CT and bone scintigraphy in the detection of bone metastases from breast cancer.

[Epidemiology and clinical features of bone metastases]

The actual improvement of epidemiologic database collection concerning bone metastases of solid tumors allows us to better understand the seriousness of this evolution, its human, social and financial burden. A renewal of interest appeared with a better screening of the asymptomatic forms and by the therapeutic advances obtained by bone resorption inhibitors. They were developed in clinical trials with a specific and original methodology evaluating their efficacy on the skeletal-related events (SRE) (pain, fracture, spinal cord compression, pathologic fracture and hypercalcemia). It is a major concern for the clinician, whatever his specialization (medical oncology, radiotherapist, surgeon, supportive care expert), to recognize these SRE for an early diagnosis and treatment since they are, with the primary tumor, the most important prognostic factors for patient's survival.

Walker 256/B malignant breast cancer cells improve femur angioarchitecture and disrupt hematological parameters in a rat model of tumor osteolysis

This study was designed to assess femur angioarchitecture and hematological effects of Walker 256/B cells in a rat model of tumor osteolysis. Tumor osteolysis was induced by in situ inoculation of Walker 256/B malignant cells. Six other rats were sham operated and served as control. Twenty days later, rats were euthanized, and femurs were collected than radiographed. Angioarchitecture [mean lumen diameter (MLD), wall thickness (WTh), Vessel number, volume, and separation (VNb, VV, and VSp respectively)] was studied by histomorphometry at 2 different positions (P1: diaphysis, and P2: metaphysis) of the operated femora. Some hematological parameters were also assessed. Walker 256/B induced marked tumor osteolysis, with cortical perforation and trabecular destruction, associated increase in bone vascularization (increases of VNb and VV and decrease of VSp). Angioarchitecture of W256/B rats was disorganized and showed large MLD and lower WTh. These effects were more prominent in P2. When compared to Sham group, significantly decreases at levels of red blood cell (RBC), hemoglobin (Hb), hematocrit (Ht), and white blood cell (WBC) were observed in W256/B rats. These results suggest that Walker 256/B cells induced tumor osteolysis, improve hypervasculature especially near the tumoral foci (P2) associated hematological disruption. Besides, tumor vessels showed abnormal (enlarged and thinner) and disorganized morphology.

Mammary cancer bone metastasis follow-up using multimodal small-animal MR and PET imaging

Despite tremendous progress in the management of breast cancer, the survival rate of this disease is still correlated with the development of metastases-most notably, those of the bone. Diagnosis of bone metastasis requires a combination of multiple imaging modalities. MR imaging remains the best modality for soft-tissue visualization, allowing for the distinction between benign and malignant lesions in many cases. On the other hand, PET imaging is frequently more specific at detecting bone metastasis by measuring the accumulation of radiotracers, such as (18)F-sodium fluoride ((18)F-NaF) and (18)F-FDG. Thus, the main purpose of this study was to longitudinally monitor bone tumor progression using PET/MR image coregistration to improve noninvasive imaging-assisted diagnoses.

METHODS

After surgical implantation of mammary MRMT-1 cells in a rat femur, we performed minimally invasive imaging procedures at different time points throughout tumor development. The procedure consisted of sequential coregistered MR and PET image acquisition, using gadolinium-diethylenetriaminepentaacetic acid (DTPA) as a contrast agent for MR imaging and (18)F-FDG, (11)C-methionine, and (18)F-NaF as molecular tracers for PET imaging. The animals were then euthanized, and complementary radiologic (micro-CT scans) and histologic analyses were performed.

RESULTS

In this preclinical study, we demonstrated that coregistered MR and PET images provide helpful information in a rat mammary-derived bone cancer model. First, MR imaging provided a high-definition anatomic resolution that made the localization of bone resorption and tumor extension detectable between days 9 and 18 after the injection of cancer cells in the medullary channel of the femur. Indeed, the calculation of mean standardized uptake value (SUVmean) and maximal SUV (SUVmax) in bone and soft-tissue regions, as defined from the gadolinium-DTPA contrast-enhanced MR images, showed (18)F-NaF uptake modifications and increased (18)F-FDG or (11)C-methionine uptake in the bone and surrounding soft tissues. (18)F-FDG and (11)C-methionine were compared in terms of the magnitude of change in their uptake and variability. We observed that (11)C-methionine SUVmean variations in the tumor were more important than those of (18)F-FDG. We also found fewer interindividual variations using SUVmean as a quantitative parameter than SUVmax.

CONCLUSION

This preclinical evaluation demonstrated that a PET/MR image coregistration protocol provided a powerful tool to evaluate bone tumor progression in a rat model of bone metastasis and that this protocol could be translated to improve the clinical outcome for metastatic breast cancer management.

A micro-imaging study linking bone cancer pain with tumor growth and bone resorption in a rat model

Bone metastases represent a frequent complication of advanced breast cancer. As tumor growth-induced bone remodeling progresses, episodes of severe pain and fractures of weight-bearing limbs increase. All of these skeletal-related events influence the patient's quality of life and survival. In the present study, we sought to determine whether some of these pain-related behaviors could be directly correlated to tumor progression and bone remodeling. For this purpose, we used a rat model of bone cancer pain based on the implantation of mammary carcinoma cells in the medullary cavity of the femur. The bone content and tumor growth were monitored over time by magnetic resonance imaging (MRI) and micro X-ray computed tomography (μCT). The same animals were evaluated for changes in their reflexive withdrawal responses to mechanical stimuli (allodynia) and weight-bearing deficits. As assessed by MRI, we found a negative correlation between tumor volume and allodynia or postural deficits throughout the experiment. Using μCT, we found that the bone volume/total volume (BV/TV) ratios for trabecular and cortical bone correlated with both mechanical hypersensitivity and weight-bearing impairment. However, whereas trabecular BV/TV stabilized between days 7 and 10 post-tumor detection, the cortical bone loss reached its maximum at that time. Our imaging approach also allowed us to consistently detect the tumor before the onset of pain, paving the way for the preemptive identification of at-risk patients. Altogether, these results improve our understanding of the events leading to tumor-induced bone pain and could eventually help in the design of novel strategies for the management of bone diseases.