Study on the microscopic structure of clathrate hydrate has made significant progress in the past decades. This review aims to summarize the state of the art of the experimental characterization of ...guest molecular occupancy in clathrate hydrate cages, which is an important area of the microscopic structures. The characterizing method and features of different guest molecular, such as hydrocarbon, carbon dioxide, hydrogen and inhibitor/promoter, in different hydrate cages have been extensively reviewed. A comprehensive use of advanced technologies such as X-ray diffraction, Raman spectroscopy and nuclear magnetic resonance may provide better understanding on the compositions and microscopic mechanisms of clathrate hydrate.
Background
Lymphedema (LE) after axillary lymph node dissection (ALND) is a multifactorial, chronic, and disabling condition that currently affects an estimated 4 million people worldwide. Although ...several risk factors have been described, it is difficult to estimate the risk in individual patients. We therefore developed nomograms based on a large data set.
Methods
Clinicopathologic features were collected from a prospective cohort comprising 1,054 women with unilateral breast cancer undergoing ALND as part of their surgical treatment from August 2001 to November 2002. LE was defined as a volume difference of at least 200 ml between arms at 6 months or more after surgery. The cumulative incidence of LE was ascertained by the Kaplan–Meier method, and Cox proportional hazard models were used to predict the risk of developing LE on the basis of the available data at each time point: model 1, preoperatively; model 2, within 6 months from surgery; and model 3, at 6 months or later after surgery.
Results
The 5 year cumulative incidence of LE was 30.3%. Independent risk factors for LE were age, body mass index, ipsilateral arm chemotherapy infusions, level of ALND, location of radiotherapy field, development of postoperative seroma, infection, and early edema. When applied to the validation set, the concordance indices were 0.706, 0.729, and 0.736 for models 1, 2, and 3, respectively.
Conclusions
The proposed nomograms can help physicians and patients predict the 5 year probability of LE after ALND for breast cancer. Free online versions of the nomograms are available at
http://www.lymphedemarisk.com/
.
Objective To compare the ability of clinicians vs a nomogram at predicting future bone scan positivity in patients with prostate cancer. Materials and Methods This investigation was conducted during ...an advisory board meeting in June 2011. Details of 25 androgen deprivation therapy-naive prostate cancer patients were given to 24 prostate cancer experts, including urologists and oncologists. The clinicians were asked to predict the probability that the patients would have a positive bone scan if left untreated for 1 year. These predictions and those of the Slovin nomogram were compared with the actual occurrence of metastatic disease, and the discrimination ability was quantified using the concordance index (C index). Results A higher C index value was obtained with the Slovin nomogram (0.812) than with the clinicians (0.628). The nomogram outperformed all of the clinicians; individual clinician C index values varied between 0.47 and 0.75. The urologists provided superior predictions compared with the oncologists. Conclusion Future bone scan positivity can be predicted more accurately using a nomogram than by expert clinicians. Nomograms should, therefore, become an integral part of the clinical decision-making process in the prostate cancer setting for patients with a rising prostate-specific antigen level after radical prostatectomy.
Development of user-friendly tools for the prediction of single-patient probability of late rectal toxicity after conformal radiotherapy for prostate cancer.
This multicenter protocol was ...characterized by the prospective evaluation of rectal toxicity through self-assessed questionnaires (minimum follow-up, 36 months) by 718 adult men in the AIROPROS 0102 trial. Doses were between 70 and 80 Gy. Nomograms were created based on multivariable logistic regression analysis. Three endpoints were considered: G2 to G3 late rectal bleeding (52/718 events), G3 late rectal bleeding (24/718 events), and G2 to G3 late fecal incontinence (LINC, 19/718 events).
Inputs for the nomogram for G2 to G3 late rectal bleeding estimation were as follows: presence of abdominal surgery before RT, percentage volume of rectum receiving >75 Gy (V75Gy), and nomogram-based estimation of the probability of G2 to G3 acute gastrointestinal toxicity (continuous variable, which was estimated using a previously published nomogram). G3 late rectal bleeding estimation was based on abdominal surgery before RT, V75Gy, and NOMACU. Prediction of G2 to G3 late fecal incontinence was based on abdominal surgery before RT, presence of hemorrhoids, use of antihypertensive medications (protective factor), and percentage volume of rectum receiving >40 Gy.
We developed and internally validated the first set of nomograms available in the literature for the prediction of radio-induced toxicity in prostate cancer patients. Calculations included dosimetric as well as clinical variables to help radiation oncologists predict late rectal morbidity, thus introducing the possibility of RT plan corrections to better tailor treatment to the patient's characteristics, to avoid unnecessary worsening of quality of life, and to provide support to the patient in selecting the best therapeutic approach.
Purpose Radical prostatectomy, external beam radiotherapy and brachytherapy are accepted treatments for localized prostate cancer. However, it is unknown if survival differences exist among ...treatments. We analyzed the survival of patients treated with these modalities according to contemporary standards. Materials and Methods A total of 10,429 consecutive patients with localized prostate cancer treated with radical prostatectomy (6,485), external beam radiotherapy (2,264) or brachytherapy (1,680) were identified. Multivariable regression analyses were used to model the disease (biopsy grade, clinical stage, prostate specific antigen) and patient specific (age, ethnicity, comorbidity) parameters for overall survival and prostate cancer specific mortality. Propensity score analysis was used to adjust for differences in observed background characteristics. Results The adjusted 10-year overall survival after radical prostatectomy, external beam radiotherapy and brachytherapy was 88.9%, 82.6% and 81.7%, respectively. Adjusted 10-year prostate cancer specific mortality was 1.8%, 2.9% and 2.3%, respectively. Using propensity score analysis, external beam radiotherapy was associated with decreased overall survival (HR 1.6, 95% CI 1.4–1.9, p <0.001) and increased prostate cancer specific mortality (HR 1.5, 95% CI 1.0–2.3, p = 0.041) compared to radical prostatectomy. Brachytherapy was associated with decreased overall survival (HR 1.7, 95% CI 1.4–2.1, p <0.001) but not prostate cancer specific mortality (HR 1.3, 95% CI 0.7–2.4, p = 0.5) compared to radical prostatectomy. Conclusions After adjusting for major confounders, radical prostatectomy was associated with a small but statistically significant improvement in overall and cancer specific survival. These survival differences may arise from an imbalance of confounders, differences in treatment related mortality and/or improved cancer control when radical prostatectomy is performed as initial therapy.
Objectives
The objective of this study was to create a nomogram predictive of survival in salivary gland cancer.
Methods
Clinical, tumor, and treatment characteristics were collected for 301 patients ...who underwent surgery for salivary gland cancer between 1985 and 2009 at Memorial Sloan Kettering Cancer Centre. Factors predictive of overall survival (OS) and cancer-specific survival (CSS) were determined by univariate analysis. Cox risk regression was used to model OS data. Competing risks regression was used for cancer-specific death. Deaths from other causes were treated as competing risks for cancer-specific death. Predictive nomograms for OS and CSS were then created using stepdown method to select predictors of outcome.
Results
The median age was 62 (range 9–89) years. There were 156 (52 %) males and 145 (48 %) females. Five variables predictive for OS (age, clinical T4 stage, histological grade, perineural invasion, and tumor dimension) were used to generate a parsimonious model, and a nomogram was created to predict 10-year survival probability. The concordance index (CI) for this nomogram was 0.809. Five variables predictive for CSS (histological grade, perineural invasion, clinical T4 stage, positive nodal status, and status of margins) were used to generate a second nomogram predicting CSS. This nomogram had a CI of 0.856. Both nomograms were validated internally by assessing discrimination and calibration.
Conclusions
We have developed the first nomograms to predict prognosis in an individual patient with salivary gland cancer.
Background Older women with early-stage breast cancer experience higher rates of non–breast cancer-related death. We examined factors associated with cause-specific death in a large cohort of breast ...cancer patients treated with extended adjuvant endocrine therapy. Methods In the MA.17 trial, conducted by the National Cancer Institute of Canada Clinical Trials Group, 5170 breast cancer patients (median age = 62 years; range = 32–94 years) who were disease free after approximately 5 years of adjuvant tamoxifen treatment were randomly assigned to treatment with letrozole (2583 women) or placebo (2587 women). The median follow-up was 3.9 years (range0–7 years). We investigated the association of 11 baseline factors with the competing risks of death from breast cancer, other malignancies, and other causes. All statistical tests were two-sided likelihood ratio criterion tests. Results During follow-up, 256 deaths were reported (102 from breast cancer, 50 from other malignancies, 100 from other causes, and four from an unknown cause). Non–breast cancer deaths accounted for 60% of the 252 known deaths (72% for those ≥70 years and 48% for those <70 years). Two baseline factors were differentially associated with type of death: cardiovascular disease was associated with a statistically significant increased risk of death from other causes (P.002), and osteoporosis was associated with a statistically significant increased risk of death from other malignancies (P.05). An increased risk of breast cancer–specific death was associated with lymph node involvement (P < .001). Increased risk of death from all three causes was associated with older age (P < .001). Conclusions Non–breast cancer-related deaths were more common than breast cancer–specific deaths in this cohort of 5-year breast cancer survivors, especially among older women.
For each clinical circumstance, the benefits of transvenous lead extraction (TLE) need to be weighed against the risks. Clinical decision-making tools for predicting mortality after TLE are lacking.
...To create a preoperative risk score for prediction of 30-day all-cause mortality after TLE of pacemaker and defibrillator leads.
Consecutive patients undergoing TLE at the Cleveland Clinic between August 1996 and August 2011 were included in the analysis. A risk nomogram for predicting 30-day all-cause mortality was developed using baseline clinical variables and multivariable logistic regression modeling. Discrimination and calibration were assessed by using bootstrapping for internal validation. Continuous data are presented as median (25th, 75th percentile); categorical data are presented as number (percentage).
A total of 5521 (4137 74.9% pacemaker and 1384 25.1% defibrillator) leads were extracted during 2999 TLE procedures (patient age 67.2 55.2, 76.2 years, 30.2% female). Lead implant duration was 4.7 (2.4, 8.3) years and 2.0 (1.0, 2.0) leads were extracted per procedure. Sixty-seven patients (2.2%) had died by 30 days after TLE. Variables with the highest predictive value for 30-day all-cause mortality included age, body mass index, hemoglobin, end-stage renal disease, left ventricular ejection fraction, New York Heart Association functional class, extraction for infection, number of prior lead extractions performed by the operator, and extraction of a dual-coil defibrillator lead. These variables were used to create a nomogram with a bootstrap-corrected concordance index value of 0.867.
Thirty-day all-cause mortality after TLE can be assessed with good discriminative power using readily available clinical information.
Abstract Background Medical comorbidity is a confounding factor in prostate cancer (PCa) treatment selection and mortality. Large-scale comparative evaluation of PCa mortality (PCM) and overall ...mortality (OM) restricted to men without comorbidity at the time of treatment has not been performed. Objective To evaluate PCM and OM in men with no recorded comorbidity treated with radical prostatectomy (RP), external-beam radiation therapy (EBRT), or brachytherapy (BT). Design, setting, and participants Data from 10 361 men with localized PCa treated from 1995 to 2007 at two academic centers in the United States were prospectively obtained at diagnosis and retrospectively reviewed. We identified 6692 men with no recorded comorbidity on a validated comorbidity index. Median follow-up after treatment was 7.2 yr. Intervention Treatment with RP in 4459 men, EBRT in 1261 men, or BT in 972 men. Outcome measurements and statistical analysis Univariate and multivariate Cox proportional hazards regression analysis, including propensity score adjustment, compared PCM and OM for EBRT and BT relative to RP as reference treatment category. PCM was also evaluated by competing risks analysis. Results and limitations Using Cox analysis, EBRT was associated with an increase in PCM compared with RP (hazard ratio HR: 1.66; 95% confidence interval CI, 1.05–2.63), while there was no statistically significant increase with BT (HR: 1.83; 95% CI, 0.88–3.82). Using competing risks analysis, the benefit of RP remained but was no longer statistically significant for EBRT (HR: 1.55; 95% CI, 0.92–2.60) or BT (HR: 1.66; 95% CI, 0.79–3.46). In comparison with RP, both EBRT (HR: 1.71; 95% CI, 1.40–2.08) and BT (HR: 1.78; 95% CI, 1.37–2.31) were associated with increased OM. Conclusions In a large multicenter series of men without recorded comorbidity, both forms of radiation therapy were associated with an increase in OM compared with surgery, but there were no differences in PCM when evaluated by competing risks analysis. These findings may result from an imbalance of confounders or differences in mortality related to primary or salvage therapy.
OBJECTIVE: Sulfonylureas have historically been analyzed as a medication class, which may be inappropriate given the differences in properties inherent to the individual sulfonylureas (hypoglycemic ...risk, sulfonylurea receptor selectivity, and effects on myocardial ischemic preconditioning). The purpose of this study was to assess the relationship of individual sulfonylureas and the risk of overall mortality in a large cohort of patients with type 2 diabetes. RESEARCH DESIGN AND METHODS: A retrospective cohort study was conducted using an academic health center enterprise-wide electronic health record (EHR) system to identify 11,141 patients with type 2 diabetes (4,279 initiators of monotherapy with glyburide, 4,325 initiators of monotherapy with glipizide, and 2,537 initiators of monotherapy with glimepiride), ≥18 years of age with and without a history of coronary artery disease (CAD) and not on insulin or a noninsulin injectable at baseline. The patients were followed for mortality by documentation in the EHR and Social Security Death Index. Multivariable Cox models were used to compare cohorts. RESULTS: No statistically significant difference in the risk of overall mortality was observed among these agents in the entire cohort, but we did find evidence of a trend toward an increased overall mortality risk with glyburide versus glimepiride (hazard ratio 1.36 95% CI 0.96-1.91) and glipizide versus glimepiride (1.39 0.99-1.96) in those with documented CAD. CONCLUSIONS: Our results did not identify an increased mortality risk among the individual sulfonylureas but did suggest that glimepiride may be the preferred sulfonylurea in those with underlying CAD.
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