Abstract 233: A Network Meta-analysis Comparing The Performance Of Magnetic Resonance Imaging, Positron Emission Tomography And Bone Scintigraphy Techniques In Detecting Cardiac Amyloidosis

Aims: Diagnosing cardiac amyloidosis with non-invasive imaging studies can be challenging. We aims to systematically review the published literature and compare the performance of magnetic resonance (CMR), positron emission tomography (PET) and bone scintigraphy (BS) for diagnosis of cardiac amyloidosis.

Methods: Medical electronic databases were searched for studies evaluating the diagnostic performance of CMR, PET or BS in diagnosing cardiac amyloidosis where histopathological examination of endomyocardial biopsy tissue or extra-cardiac organs were used as reference standards. We evaluated; CMR: extracellular volume (ECV), late gadolinium enhancement (LGE), T1 mapping; PET: F18-Amyloid, F18-Sodium Fluoride (NaF), and C11-PIB; BS: Technetium-99m (Tc) hydroxymethylene diphosphonate (Tc-HMDP), Tc-3,3-diphosphono-1,2-propanodicarboxylicacid (Tc-DPD), Tc- pyrophosphate (Tc-PYP). Methodological quality was assessed using a Quality Assessment of Diagnostic Accuracy Studies 2 (QUADAS-2). To summarize sensitivity, specificity, and superiority, we used an arm-based hierarchical model which expresses the logit transformed sensitivity and specificity as the sum of fixed effects for test, correlated study-effects to model the inherent correlation between sensitivity and specificity and a random error associated with various tests evaluated in each study.

Results: Of the 2871 studies identified, 39 studies met the inclusion criteria. Sensitivity and specificity and Superiority of the various imaging modalities in diagnosing cardiac amyloidosis were calculated (Figure).

Study quality assessed by QUADAS-2 was generally good with negligible evidence of bias.

Conclusion: Various non-invasive imaging modalities have been studied for diagnosing cardiac amyloidosis with varying sensitivity and specificity. Comparative studies may be warranted to improve non-invasive diagnostic algorithms of suspected cardiac amyloidosis.

Breast cancer sentinel node identification and classification after neoadjuvant chemotherapy-systematic review and meta analysis

RATIONALE AND OBJECTIVES

Breast cancer is the leading cause of mortality in women worldwide. Lymphatic mapping with sentinel node biopsy has the potential to reduce the morbidity associated with breast cancer staging in women after neoadjuvant therapy.

MATERIALS AND METHODS

A systematic search of world literature between 1996 and 2007 of sentinel node mapping in patients with early-stage breast carcinoma after chemotherapy was undertaken. Potentially eligible studies were identified using database-specific search strategies incorporating appropriate Boolean combinations of the keywords sentinel node biopsy or sentinel node localization or lymphatic mapping; breast cancer or malignancy or neoplasm; and preoperative or neoadjuvant chemotherapy. The electronic searches were augmented with a manual search of reference lists from identified articles. Successful lymph node mapping, defined as successful identification rate (SIR), and false-negative rate (FNR) was summarized using a bivariate random effects mixed model. The extent of heterogeneity was assessed using the inconsistency statistic. The effect of study level covariates, such as use of immunohistochemistry or dual mapping technique, and individual quality criteria, such as study design or multi-institution participation, on SIR and FNR were analyzed using metaregression.

RESULTS

A total of 24 trials of 1799 subjects were reported that met eligibility criteria. All studies identified were published between 2000 and 2007. Lymph node involvement was found in 758 patients (37%) and ranged from 25% to 96% across studies. The proportion of patients who had successful lymph node mapping ranged from 63% to 100%, with 79% of studies reporting a rate of less than 95%. The summary successful identification rate was 0.896 (95% confidence interval [CI] 0.860-0.923) with moderate heterogeneity. The summary FNR was 0.084 (95% CI 0.064-0.109) with no significant heterogeneity. Increasing prevalence of lymph node involvement and same-day mapping and lymph node dissection both significantly reduced the FNR.

CONCLUSIONS

The present systematic review demonstrates robust estimates of successful identification rate and false-negative rates of sentinel lymph node mapping and biopsy after neoadjuvant therapy for early-stage breast cancer patients. With a 90% SIR and 8% FNR, this technique is a reliable tool for planning treatment in this population as an alternative to completion axillary lymph node dissection.

MRI and mammography surveillance of women at increased risk for breast cancer: recommendations using an evidence-based approach

RATIONALE AND OBJECTIVES

To evaluate breast cancer screening with mammography and magnetic resonance imaging (MRI) in high-risk populations, including women with the BRCA mutation, using an evidence-based approach.

METHODS

The MEDLINE, PubMed, EBM Reviews, ACP Journal Club, Cochrane Database MEDSEARCH, and SCOPUS databases were accessed and searched for articles up to August 2007. Articles were collected using the following terms and medical subject headings (MeSH) that applied to the focused clinical question: "BRCA1" and "BRCA2" with "mammography," "MRI," "prevention," "screening," and "surveillance." References from retrieved articles were also used to identify relevant papers. Abstracts were screened and relevant papers retrieved. Retrieved papers were graded for quality. Summary performance measures were obtained by random effects modeling of study-specific performance estimates and standard errors derived from the multiple 2 x 2 tables. Additionally, studies meeting the Centre for Evidence-Based Medicine level 2b quality were reviewed.

RESULTS

In women with an increased risk without the BRCA gene, cancer detection rates by MRI were 0.011 (95% confidence interval [CI] 0.003-0.019), by mammography 0.005 (95% CI 0.002-0.008), and by a combination of both, 0.012 (95% CI 0.004-0.020). False-positive rates by MRI, mammography, or a combination of both were 0.10 (95% CI 0.03-0.18), 0.05 (95% CI 0.03-0.06), and 0.14 (95% CI 0.04-0.24). In BRCA positive women, cancer detection rates by MRI were 0.027 (95% CI 0.015-0.040), by mammography 0.010 (95% CI 0.005-0.016), and by a combination of both 0.031 (95% CI 0.018-0.045). False-positive rates by MRI, mammography, or a combination of both were 0.10 (95% CI 0.01-0.19), 0.05 (95% CI 0.03-0.07), and 0.14 (95% CI 0.04-0.24), respectively.

CONCLUSIONS

The data support an essential role for screening MRI in women with an increased risk for breast cancer.

Meta-analysis: effectiveness of drugs for preventing contrast-induced nephropathy

BACKGROUND

N-Acetylcysteine, theophylline, and other agents have shown inconsistent results in reducing contrast-induced nephropathy.

PURPOSE

To determine the effect of these agents on preventing nephropathy.

DATA SOURCES

Relevant randomized, controlled trials were identified by computerized searches in MEDLINE (from 1966 through 3 November 2006), EMBASE (1980 through November 2006), PubMed, Web of Knowledge (Current Contents Connect, Web of Science, BIOSIS Previews, and ISI Proceedings for the latest 5 years), and the Cochrane Library databases (up to November 2006). Databases were searched for studies in English, Spanish, French, Italian, and German.

STUDY SELECTION

Randomized, controlled trials that administered N-acetylcysteine, theophylline, fenoldopam, dopamine, iloprost, statin, furosemide, or mannitol to a treatment group; used intravenous iodinated contrast; defined contrast-induced nephropathy explicitly; and reported sufficient data to construct a 2 x 2 table of the primary effect measure.

DATA EXTRACTION

Abstracted information included patient characteristics, type of contrast media and dose, periprocedural hydration, definition of contrast-induced nephropathy, and prophylactic agent dose and route.

DATA SYNTHESIS

In the 41 studies included, N-acetylcysteine (relative risk, 0.62 [95% CI, 0.44 to 0.88]) and theophylline (relative risk, 0.49 [CI, 0.23 to 1.06]) reduced the risk for contrast-induced nephropathy more than saline alone, whereas furosemide increased it (relative risk, 3.27 [CI, 1.48 to 7.26]). The remaining agents did not significantly affect risk. Significant subgroup heterogeneity was present only for N-acetylcysteine. No publication bias was discerned.

LIMITATIONS

All trials evaluated the surrogate end point of contrast-induced nephropathy as the primary outcome. The lack of a statistically significant renoprotective effect of theophylline may result from insufficient data or study heterogeneity. True study quality remains uncertain.

CONCLUSION

N-acetylcysteine is more renoprotective than hydration alone. Theophylline may also reduce risk for contrast-induced nephropathy, although the detected association was not significant. Our data support the administration of N-acetylcysteine prophylaxis, particularly in high-risk patients, given its low cost, availability, and few side effects.