2 Minute Medicine Rewind September 1 – September 8, 2014

In this section, we highlight the key high-impact studies, updates, and analyses published in medicine during the past week.

Use of and Mortality After Bilateral Mastectomy Compared With Other Surgical Treatments for Breast Cancer in California, 1998-2011

Despite studies showing similar survival for patients with early-stage breast cancer treated with breast-conserving surgery plus radiation therapy or with mastectomy, there has been an increasing use of mastectomy (often bilateral), which has been partly attributed to an increase in genetic testing. Given bilateral mastectomy may have increased medical complications and physical disfigurement, a better understanding of its use and outcomes is crucial to improving cancer care. In this observational cohort study, 189 734 women diagnosed with stages 0-III unilateral breast cancer in California were followed from 1998 through 2011. During this time period, the overall rate of bilateral mastectomy increased from 2.0% (95% CI, 1.7%-2.2%) to 12.3% (95% CI, 11.8%-12.9%), and from 3.6% (95% CI, 2.3%-5.0%) to 33% (95% CI, 29.8%-36.5%) among women younger than 40 years. Non-Hispanic white women, those with private insurance, and those who received care at a National Cancer Institute–designated cancer center were more likely to elect a bilateral mastectomy. Unilateral mastectomy was associated with higher all-cause mortality (hazard ratio [HR], 1.35 [95% CI, 1.32-1.39] and 10-year mortality, 20.1% [95% CI, 19.9%-20.4%]) when compared with breast-conserving surgery with radiation (10-year mortality, 16.8% [95% CI, 16.6%-17.1%]). Bilateral mastectomy was associated with no significant mortality difference when compared with breast-conserving surgery with radiation (HR, 1.02 [95% CI, 0.94-1.11]; 10-year mortality, 18.8% [95% CI, 18.6%-19.0%]). Thus, in the setting of increased mortality rate, unilateral mastectomy should be avoided. Given similar mortality rates for the other two surgical options, medical and psychosocial complications should be taken into account when electing a treatment of choice.

Effect of Reversible Intermittent Intra-abdominal Vagal Nerve Blockade on Morbid Obesity

The ReCharge Randomized Clinical Trial

Given the morbidity risks associated with bariatric surgery, there has been interest in finding other equally effective weight loss options. The vagus nerve is involved in satiety, metabolism, and upper gastrointestinal track autonomic control; thus, blocking vagal activity through electrodes implanted during minimally invasive laparoscopic surgery has been proposed as an alternative treatment option. In this randomized-controlled trial, 162 patients were randomized to receive, in addition to weight management education, an active vagal nerve block device or a sham device. The mean excess weight loss was 24.4% (9.2% of their initial body weight loss) in the vagal nerve block group compared to 15.9% excess weight loss (6.0% initial body weight loss) in the sham group (P  = .002). One year post-treatment, 52% and 38% of the vagal nerve block group participants achieved 20% and 25% or more weight loss, respectively, compared to 32% and 23% in the sham group, respectively. The rate of serious adverse events related with the vagal block procedure was 3.7% (95% CI, 1.4%-7.9%), with the most common adverse effects being dyspepsia and mild to moderate abdominal pain. Thus, although treatment with vagus nerve blockade did not meet the efficacy objective set by the research team, it did prove to be safe and led to higher weight loss than placebo.

Autologous Transplantation and Maintenance Therapy in Multiple Myeloma

Although high-dose chemotherapy plus autologous stem-cell transplantation has been shown to prolong survival in multiple myeloma patients when compared to conventional chemotherapy, autologous stem-cell transplantation has substantial toxic effects; ongoing comparisons with less toxic, orally administered treatments are thus crucial. In this open-label, randomized, phase 3 trial, 273 were randomized to high-dose melphalan plus stem-cell transplantation or melphalan–prednisone–lenalidomide (MPR) consolidation therapy after induction, and 251 patients were randomized to lenalidomide maintenance therapy or no maintenance therapy. High-dose melphalan plus stem-cell transplantation lead to significantly longer progression-free and overall survival than with MPR (median progression-free survival, 43.0 months vs. 22.4 months; hazard ratio for progression or death, 0.44; 95% confidence interval [CI], 0.32 to 0.61; P<0.001; and 4-year overall survival, 81.6% vs. 65.3%; hazard ratio for death, 0.55; 95% CI, 0.32 to 0.93; P=0.02). Lenalidomide maintenance similarly significantly prolonged median progression-free survival compared to no maintenance (41.9 months vs. 21.6 months; hazard ratio for progression or death, 0.47; 95% CI, 0.33 to 0.65; P<0.001). Rates of adverse effects were higher in the transplantation group; grade 3 or 4 neutropenia was present in 94.3% of patients (compared to 51.5% in the MPR group). Lenalidomine maintenance also had higher adverse effect rates than no maintenance, including neutropenia (23.3% vs. 0%) and dermatologic toxic effects (4.3% vs. 0%).Thus, although both autologous stem cell transplantation and lenalidomine maintenance therapy come with increased adverse effects, they continue to show prolonged survival for multiple myeloma patients.

Association of Socioeconomic Status, Race, and Ethnicity With Outcomes of Patients Undergoing Thyroid Surgery

Despite improvements in health care that have led to advances in the management of a variety of diseases, gaps between patients of different races, ethnicities, and socioeconomic status have shown little change; it is thus imperative to continue to examine their influence on outcomes for a variety of surgical procedures. In this cross-sectional analysis, 62 722 thyroid procedures performed between 2003 and 2009 were reviewed. Surgeons with low volumes of thyroid surgery, who performed the majority (90.8%) of thyroid surgeries in the United States, had higher rates of postoperative complications compared with surgeons with higher volume (17.2% vs 12.1%; P < .001). Similarly, complications (17.7% vs 15.1%; P < .001) and hospital length of stay (1.85 [0.02] vs 1.57 [0.03] days; P  = .001) were higher and longer, respectively, in low volume compared to high volume centers. Hispanics were more likely to be operated on by low-volume surgeons (odds ratio [OR], 2.04; 95% CI, 1.19-3.48). This was also the case for black patients in certain regions of the United States. Patients with Medicare (OR, 1.30; 95% CI, 1.13-1.53) and lower income (OR, 1.73; 95% CI, 1.19-2.53) were more likely to be treated at low-volume centers. Thus, the gap in thyroid surgery outcomes is linked to a disparity in access to high-volume hospitals and surgeons.

Comparison of Weight Loss Among Named Diet Programs in Overweight and Obese Adults

The diet industry, a multibillion dollar industry, provides structured dietary and lifestyle recommendations for Americans trying to lose weight; however, objective data on these dietsis often hard to obtain. In this meta-analysis, 48 randomized trials (including 7286 individuals) were reviewed. Low-carbohydrate and low-fat diets showed the largest weight loss. Low-carbohydrate diets averaged a 8.73 kg [95% credible interval {CI}, 7.27 to 10.20 kg] weight loss at 6 months and 7.25 kg [95% CI, 5.33 to 9.25 kg] at 12 months, while low-fat diets averaged a 7.99 kg weight loss [95% CI, 6.01 to 9.92 kg] at 6 months and 7.27 kg [95% CI, 5.26 to 9.34 kg] at 12 months. Given very little difference was seen between individual diets with similar principles, the best low-carbohydrate or low-fat diet to recommend is one that the patient will adhere to in order to lose weight.

Image: PD

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