Pre-operative sentinel lymph node localization in breast cancer with superparamagnetic iron oxide MRI: the SentiMAG Multicentre Trial imaging subprotocol

Objective:

Sentinel lymph node biopsy (SLNB) with a superparamagnetic iron oxide (SPIO) tracer was shown to be non-inferior to the standard combined technique in the SentiMAG Multicentre Trial. The MRI subprotocol of this trial aimed to develop a magnetic alternative for pre-operative lymphoscintigraphy (LS). We evaluated the feasibility of using MRI following the administration of magnetic tracer for pre-operative localization of sentinel lymph nodes (SLNs) and its potential for non-invasive identification of lymph node (LN) metastases.

Methods:

Patients with breast cancer scheduled to undergo SLNB were recruited for pre-operative LS, single photon emission CT (SPECT)-CT and SPIO MRI. T₁ weighted turbo spin echo and T₂ weighted gradient echo sequences were used before and after interstitial injection of magnetic tracer into the breast. SLNs on MRI were defined as LNs with signal drop and direct lymphatic drainage from the injection site. LNs showing inhomogeneous SPIO uptake were classified as metastatic. During surgery, a handheld magnetometer was used for SLNB. Blue or radioactive nodes were also excised. The number of SLNs and MR assessment of metastatic involvement were compared with surgical and histological outcomes.

Results:

11 patients were recruited. SPIO MRI successfully identified SLNs in 10 of 11 patients vs 11 of 11 patients with LS/SPECT-CT. One patient had metastatic involvement of four LNs, and this was identified in one node on pre-operative MRI.

Conclusion:

SPIO MRI is a feasible technique for pre-operative localization of SLNs and, in combination with intraoperative use of a handheld magnetometer, provides an entirely radioisotope-free technique for SLNB. Further research is needed for the evaluation of MRI characterization of LN involvement using subcutaneous injection of magnetic tracer.

Advances in knowledge:

This study is the first to demonstrate that an interstitially administered magnetic tracer can be used both for pre-operative imaging and intraoperative SLNB, with equal performance to imaging and localization with radioisotopes.     

2015 Marshall Urist Young Investigator Award: Prognostication in Patients With Long Bone Metastases: Does a Boosting Algorithm Improve Survival Estimates?

Background

Survival estimation guides surgical decision-making in metastatic bone disease. Traditionally, classic scoring systems, such as the Bauer score, provide survival estimates based on a summary score of prognostic factors. Identification of new factors might improve the accuracy of these models. Additionally, the use of different algorithms—nomograms or boosting algorithms—could further improve accuracy of prognostication relative to classic scoring systems. A nomogram is an extension of a classic scoring system and generates a more-individualized survival probability based on a patient’s set of characteristics using a figure. Boosting is a method that automatically trains to classify outcomes by applying classifiers (variables) in a sequential way and subsequently combines them. A boosting algorithm provides survival probabilities based on every possible combination of variables.

Questions/purposes

We wished to (1) assess factors independently associated with decreased survival in patients with metastatic long bone fractures and (2) compare the accuracy of a classic scoring system, nomogram, and boosting algorithms in predicting 30-, 90-, and 365-day survival.

Methods

We included all 927 patients in our retrospective study who underwent surgery for a metastatic long bone fracture at two institutions between January 1999 and December 2013. We included only the first procedure if patients underwent multiple surgical procedures or had more than one fracture. Median followup was 8 months (interquartile range, 3-25 months); 369 of 412 (90%) patients who where alive at 1 year were still in followup. Multivariable Cox regression analysis was used to identify clinical and laboratory factors independently associated with decreased survival. We created a classic scoring system, nomogram, and boosting algorithms based on identified variables. Accuracy of the algorithms was assessed using area under the curve analysis through fivefold cross validation.

Results

The following factors were associated with a decreased likelihood of survival after surgical treatment of a metastatic long bone fracture, after controlling for relevant confounding variables: older age (hazard ratio [HR], 1.0; 95% CI, 1.0–1.0; p < 0.001), additional comorbidity (HR, 1.2; 95% CI, 1.0–1.4; p = 0.034), BMI less than 18.5 kg/m² (HR, 2.0; 95% CI, 1.2–3.5; p = 0.011), tumor type with poor prognosis (HR, 1.8; 95% CI, 1.6–2.2; p < 0.001), multiple bone metastases (HR, 1.3; 95% CI, 1.1–1.6; p = 0.008), visceral metastases (HR, 1.6; 95% CI, 1.4–1.9; p < 0.001), and lower hemoglobin level (HR, 0.91; 95% CI, 0.87–0.96; p < 0.001). The survival estimates by the nomogram were moderately accurate for predicting 30-day (area under the curve [AUC], 0.72), 90-day (AUC, 0.75), and 365-day (AUC, 0.73) survival and remained stable after correcting for optimism through fivefold cross validation. Boosting algorithms were better predictors of survival on the training datasets, but decreased to a performance level comparable to the nomogram when applied on testing datasets for 30-day (AUC, 0.69), 90-day (AUC, 0.75), and 365-day (AUC, 0.72) survival prediction. Performance of the classic scoring system was lowest for all prediction periods.

Conclusions

Comorbidity status and BMI are newly identified factors associated with decreased survival and should be taken into account when estimating survival. Performance of the boosting algorithms and nomogram were comparable on the testing datasets. However, the nomogram is easier to apply and therefore more useful to aid surgical decision making in clinical practice.

Level of Evidence

Level III, prognostic study.

Electronic supplementary material

The online version of this article (doi:10.1007/s11999-015-4446-z) contains supplementary material, which is available to authorized users.     

Reduced tonicity stimulates an inflammatory response in nucleus pulposus tissue that can be limited by a COX‐2‐specific inhibitor

In intervertebral disc herniation with nucleus pulposus (NP) extrusion, the elicited inflammatory response is considered a key pain mechanism. However, inflammatory cytokines are reported in extruded herniated tissue, even before monocyte infiltration, suggesting that the tissue itself initiates the inflammation. Since herniated tissue swells, we investigated whether this simple mechanobiological stimulus alone could provoke an inflammatory response that could cause pain. Furthermore, we investigated whether sustained‐release cyclooxygenase‐2 (COX2) inhibitor would be beneficial in such conditions. Healthy bovine NP explants were allowed to swell freely or confined. The swelling explants were treated with Celecoxib, applied either as a bolus or in sustained‐release. Swelling explants produced elevated levels of interleukin‐6 (IL‐6) and prostaglandin E₂ (PGE₂) for 28 days, while confined explants did not. Both a high concentration bolus and 10 times lower concentration in sustained release completely inhibited PGE₂ production, but did not affect IL‐6 production. Swelling of NP tissue, without the inflammatory system response, can trigger cytokine production and Celecoxib, even in bolus form, may be useful for pain control in extruded disc herniation. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 33:1724–1731, 2015.     

Seven-year follow-up after dobutamine stress echocardiography: impact of gender on prognosis

OBJECTIVES: The aim of this study was to investigate the effects of gender on long-term prognosis of patients undergoing dobutamine stress echocardiography (DSE). BACKGROUND: Gender differences in the predictors of outcome among patients with known or suspected coronary artery disease undergoing DSE have not been adequately studied. METHODS: We studied 2,276 men and 1,105 women with known or suspected coronary artery disease who underwent DSE. Follow-up events were cardiac death and nonfatal myocardial infarction (MI). RESULTS: Dobutamine stress echocardiography was normal in 687 men (30%) and 483 women (44%) (p <0.0001). Ischemia on DSE was present in 1,194 men (52%) and 416 women (38%) (p <0.001). During a mean follow-up of 7 +/- 3.4 years, there were 894 (26%) deaths (442 attributed to cardiac causes) and 145 (4%) nonfatal MIs. The annual cardiac event rate was 2.5% in men and 1.2% in women with normal DSE. Independent predictors of cardiac events in patients with normal DSE using a Cox proportional hazards regression analysis were male gender (hazard ratio [HR]: 1.7 [range 1.1 to 2.8]), age (HR: 1.02 [range 1.01 to 1.04]), history of heart failure (HR: 3.4 [range 1.5 to 7.9]), previous MI (HR: 1.7 [range 1.1 to 2.8]), and diabetes (HR: 2.4 [range 1.3 to 4.5]). Independent predictors of cardiac events in patients with an abnormal DSE were age (HR: 1.03 [range 1.02 to 1.04]), history of heart failure (HR: 1.7 [range 1.3 to 2.1]), diabetes (HR: 1.4 [range 1.1 to 1.8]), heart rate at rest (HR: 2.8 [range 1.4 to 5.8]), wall motion abnormalities at rest (HR: 1.06 [range 1.04 to 1.09]), and ischemia on DSE (HR: 1.04 [range 1.02 to 1.07]). Myocardial ischemia was an independent predictor of cardiac events in both men and women. CONCLUSIONS: Dobutamine stress echocardiography provides independent prognostic information in both men and women. In patients with normal DSE, gender is independently associated with cardiac events. The outcome of patients with abnormal DSE is not related to gender, after adjusting for stress echocardiographic abnormalities.     

Twitter Sentiment Predicts Affordable Care Act Marketplace Enrollment

Background

Traditional metrics of the impact of the Affordable Care Act (ACA) and health insurance marketplaces in the United States include public opinion polls and marketplace enrollment, which are published with a lag of weeks to months. In this rapidly changing environment, a real-time barometer of public opinion with a mechanism to identify emerging issues would be valuable.

Objective

We sought to evaluate Twitter’s role as a real-time barometer of public sentiment on the ACA and to determine if Twitter sentiment (the positivity or negativity of tweets) could be predictive of state-level marketplace enrollment.

Methods

We retrospectively collected 977,303 ACA-related tweets in March 2014 and then tested a correlation of Twitter sentiment with marketplace enrollment by state.

Results

A 0.10 increase in the sentiment score was associated with an 8.7% increase in enrollment at the state level (95% CI 1.32-16.13; P=.02), a correlation that remained significant when adjusting for state Medicaid expansion (P=.02) or use of a state-based marketplace (P=.03).

Conclusions

This correlation indicates Twitter’s potential as a real-time monitoring strategy for future marketplace enrollment periods; marketplaces could systematically track Twitter sentiment to more rapidly identify enrollment changes and potentially emerging issues. As a repository of free and accessible consumer-generated opinions, this study reveals a novel role for Twitter in the health policy landscape.