Increased cardiovascular risk in thyroid cancer patients taking levothyroxine: a nationwide cohort study in Korea

Objective Many thyroid cancer patients are exposed to long-term thyroid-stimulating hormone (TSH) suppression, often as lifetime treatment, and are consequently at risk for cardiovascular disease. We investigated the incidence of coronary heart disease (CHD) and ischemic stroke among thyroid cancer patients compared with matched control subjects. Design Retrospective cohort study. Methods A total of 182 419 subjects who received thyroidectomy for thyroid cancer during 2004-2012 were selected from the Korean National Health Insurance data, which cover approximately 97% of the entire Korean population. Propensity score matching was used to select non-cancer controls. Cox proportional hazards regression analysis was used to determine relative risk of coronary heart disease and ischemic stroke. Mean follow-up was 4.32 years. Results Thyroid cancer patients had elevated risk for CHD and ischemic stroke with hazard ratio (HR) of 1.15 (95% confidence interval (CI): 1.10-1.22) and 1.15 (1.09-1.22), respectively. This risk was increased in those who took a higher dosage of levothyroxine (HR: 1.47, 95% CI: 1.34-1.60 for CHD and HR: 1.56, 95% CI: 1.42-1.72 for ischemic stroke among those who took ≥170 μg/day levothyroxine). Although risk of atrial fibrillation was dose-dependently associated with levothyroxine dosage, it represents only a small proportion of ischemic stroke incidence (4.4%, 128/2914). Conclusions The risk for CHD and ischemic stroke was higher in thyroid cancer patients who received thyroidectomy, and the dosage of levothyroxine administered appears to play a major role. Greater caution is suggested for the screening and treatment of thyroid cancer and subsequent TSH suppression therapy, as well as proper management for cardiovascular disease prevention.

A new software scheme for scatter correction based on a simple radiographic scattering model

In common radiography, image contrast is often limited due mainly to scattered x-rays and noise, decreasing the quantitative usefulness of x-ray images. Several scatter reduction methods based on software correction schemes have been extensively investigated in an attempt to overcome these difficulties, most of which are based on measurement, mathematical-physical modeling, or a combination of both. However, those methods require special equipment, system geometry, and extra manual work to measure scatter characteristics. In this study, we investigated a new software scheme for scatter correction based on a simple radiographic scattering model where the intensity of the scattered x-rays was directly estimated from a single x-ray image using a weighted l¹-norm contextual regularization framework. We implemented the proposed algorithm and performed a systematic simulation and experiment to demonstrate its viability. We also conducted some clinical image studies using patient's image data of breast and L-spine to verify the clinical effectiveness of the proposed scheme. Our results indicate that the degradation of image characteristics by scattered x-rays and noise was effectively recovered by using the proposed software scheme, thus improving radiographic visibility considerably. Graphical abstract The schematic illustrations of scatter suppression methods by using a an antiscatter grid and b a scatter estimation algorithm.

Apical root displacement is a critical risk factor for apical root resorption after orthodontic treatment

OBJECTIVES:

To identify risk factors for apical root resorption (ARR) of maxillary and mandibular incisors using mathematical quantification of apical root displacement (ARD) and multiple linear mixed-effects modeling.

MATERIALS AND METHODS:

Periapical radiographs of maxillary and mandibular incisors and lateral cephalograms of 135 adults were taken before and after orthodontic treatment. ARR was measured on the periapical radiographs, and movement of central incisors was evaluated on the superimposed pre- and posttreatment lateral cephalograms. ARD was mathematically calculated from pretreatment tooth length, inclination change, and movement of the incisal edge. Linear mixed-effects model analysis was performed to identify risk factors for ARR, and standardized coefficients (SCs) were calculated to investigate the relative contribution of the risk factors to ARR.

RESULTS:

Vertical ARD showed the highest SCs for both maxillary and mandibular incisors. Horizontal ARD showed the second highest SC for mandibular incisors but was not significantly correlated with the ARR of maxillary incisors. When horizontal and vertical ARDs were included in the mixed-effects model, the use of self-ligating brackets was significantly correlated with increased ARR of mandibular incisors.

CONCLUSIONS:

ARD is a critical factor for ARR after orthodontic treatment. Careful monitoring of ARR is recommended for patients requiring significant ARD of incisors.

Report from the 19th annual Western Canadian Gastrointestinal Cancer Consensus Conference; Winnipeg, Manitoba; 29-30 September 2017

The 19th annual Western Canadian Gastrointestinal Cancer Consensus Conference (wcgccc) was held in Winnipeg, Manitoba, 29-30 September 2017. The wcgccc is an interactive multidisciplinary conference attended by health care professionals from across Western Canada (British Columbia, Alberta, Saskatchewan, and Manitoba) who are involved in the care of patients with gastrointestinal cancer. Surgical, medical, and radiation oncologists; pathologists; radiologists; and allied health care professionals participated in presentation and discussion sessions for the purpose of developing the recommendations presented here. This consensus statement addresses current issues in the management of colorectal cancer.

Risk of Coronary Heart Disease and Ischemic Stroke Incidence in Gastric Cancer Survivors: A Nationwide Study in Korea

BACKGROUND

Small studies suggest improvement of cardiovascular risk profiles and reduced cardiovascular mortality after gastrectomy for gastric cancer. In our study using national health insurance data, we investigated coronary heart disease (CHD) and ischemic stroke incidence among gastric cancer patients who received gastrectomy compared with general population controls.

METHODS

A total of 98,936 gastric cancer patients were included in the study and matched to non-cancer controls via 1:1 propensity score matching. Competing risk regression analysis was used to determine the relative risk of CHD and ischemic stroke, with cancer mortality as the competing risk. Changes in cardiovascular risk profile before and after gastrectomy were tested, and factors associated with CHD or ischemic stroke incidence among gastric cancer patients were analyzed.

RESULTS

Compared with the matched controls, gastric cancer patients who received gastrectomy were shown to have a decreased risk for both CHD (subdistribution hazard ratio [SHR] 0.60, 95% confidence interval [CI] 0.57-0.63) and ischemic stroke (SHR 0.72, 95% CI 0.69-0.75). Decreases in body mass index (BMI), blood pressure, blood sugar, and lipid and hemoglobin levels were marked after gastrectomy. Among gastric cancer patients, those who lost > 5% of their body weight were at lower risk of developing CHD (SHR 0.82, 95% CI 0.71-0.96) and ischemic stroke (SHR 0.85, 95% CI 0.75-0.98).

CONCLUSIONS

CHD and ischemic stroke risk decreased after gastrectomy. The amount of weight loss and accompanying metabolic changes seemed to mediate the reduction of such risk. Reassessment of cardiovascular risk factors after gastrectomy and consideration of cardiovascular risk in the selection of treatment modality are suggested.

Oncology education for Canadian internal medicine residents: the value of participating in a medical oncology elective rotation

Background

Despite the high incidence and burden of cancer in Canadians, medical oncology (mo) rotations are not mandatory in most Canadian internal medicine (im) residency training programs.

Methods

All im residents scheduled for a mo rotation at 4 Canadian teaching cancer centres between 1 January 2013 and 31 December 2015 were invited to complete an online survey before and after their rotation. The survey was designed to evaluate perceptions of oncology, comfort in managing cancer patients, and basic oncology knowledge.

Results

The survey was completed by 68 im residents pre-rotation and by 48 (71%) post-rotation. Cancer-related learning was acquired mostly from mo physicians in clinic (35%). Self-directed learning, didactic teaching, and resident or fellow teaching accounted for 31%, 26%, and 10% respectively of learning acquisition. Comfort level in dealing with cancer patients and patients at end of life improved to 4.0/5 from 3.2/5 (p < 0.001) and to 4.0/5 from 3.6/5 (p = 0.003) respectively. Mean knowledge assessment score improved to 83% post-rotation from 76% pre-rotation (p = 0.003), with the greatest increase observed in general knowledge of common malignancies. The 3 topics ranked as most important to learn during a mo rotation were oncologic emergencies, common complications of treatment, and approach to diagnosis of cancer.

Conclusions

A rotation in mo improves the perceptions of im residents about oncology and their comfort level in dealing with cancer patients and patients at end of life. Overall cancer knowledge is also improved. Given those benefits, im residency programs should encourage most of their residents to complete a mo rotation.

Reduced partitioning of plastic strain for strong and yet ductile precipitate-strengthened alloys

When a material that contains precipitates is deformed, the precipitates and the matrix may strain plastically by different amounts causing stresses to build up at the precipitate-matrix interfaces. If premature failure is to be avoided, it is therefore essential to reduce the difference in the plastic strain between the two phases. Here, we conduct nanoscale digital image correlation to measure a new variable that quantifies this plastic strain difference and show how its value can be used to estimate the associated interfacial stresses, which are found to be approximately three times greater in an Fe-Ni2AlTi steel than in the more ductile Ni-based superalloy CMSX-4®. It is then demonstrated that decreasing these stresses significantly improves the ability of the Fe-Ni2AlTi microstructure to deform under tensile loads without loss in strength.

J-Shaped Association Between Postoperative Levothyroxine Dosage and Fracture Risk in Thyroid Cancer Patients: A Retrospective Cohort Study

Long-term administration of supraphysiologic dosages of levothyroxine can have detrimental effect on the bone. We aimed to investigate fracture incidence among post-thyroidectomy thyroid cancer patients compared with a matched comparison group, and explore the association between levothyroxine dosage and fracture risk. From the Korean National Health Insurance database, virtually all thyroid cancer patients who received thyroidectomy in Korea from January 1, 2004 to December 31, 2012 were included. Matched subjects were selected by 1:1 propensity score matching. Cox proportional hazards regression analysis was used to determine relative risk of osteoporotic fracture. Of 185,956 thyroid cancer patients identified, fracture events were observed in 1096 subjects (0.56%) over a mean 4.35 years of follow-up. Compared to the matched comparison group, thyroid cancer patients had no elevated risk of osteoporotic fracture (hazard ratio [HR] 1.03; 95% confidence interval [CI], 0.94 to 1.12); however, the highest dosage group (≥170 μg/day) showed significantly higher risk (HR 1.25; 95% CI, 1.07 to 1.45), while the second quartile dosage group (115-144 μg/day) showed lower risk (HR 0.71; 95% CI, 0.59 to 0.84) compared to a matched comparison group. When the second quartile dosage group was considered as reference, increased fracture risk was observed in those who took either lower (first quartile: adjusted HR 1.31; 95% CI, 1.08 to 1.59) or higher dosage of levothyroxine (third quartile: adjusted HR 1.50; 95% CI, 1.26 to 1.79; fourth quartile: adjusted HR 1.79; 95% CI, 1.51 to 2.13). Thyroid cancer patients were more likely to be treated with osteoporosis medication (HR 1.22; 95% CI, 1.18 to 1.26) than the matched comparison group. Both high and low dosage of levothyroxine treatment was associated with a higher risk for fractures in a J-shaped dose-dependent manner in post-thyroidectomy patients. Future studies are needed to determine how to optimize thyroid-stimulating hormone (TSH) suppression and how to screen and manage fracture risk. © 2018 American Society for Bone and Mineral Research.

Association between dietary carbohydrate quality and the prevalence of obesity and hypertension

BACKGROUND

Dietary carbohydrate quality may play an important role in disease development. We evaluated the association between carbohydrate quality index (CQI) and the prevalence of obesity and metabolic disorders among adults in South Korea.

METHODS

We analysed 12 027 adults aged 19-64 years from the fifth Korea National Health and Nutrition Examination Survey (KNHANES). CQI was based on four criteria: crude fibre intake, dietary glycaemic index (DGI), whole grains/total grains ratio and solid carbohydrates/total carbohydrates ratio.

RESULTS

Participants with a lower CQI were younger, had a lower income and were more likely to be smokers and to drink alcohol. The highest quintile CQI group showed the lowest DGI and the lowest consumption of liquid carbohydrates and refined grains, as well as the highest consumption of solid carbohydrates, crude fibre and whole grains (P < 0.05). A higher CQI was negatively associated with the prevalence of obesity (odds ratio = 0.83; 95% confidence interval = 0.69-0.99) and hypertension (odds ratio = 0.78; 95% confidence interval = 0.61-0.99) but was not associated with other metabolic disorders.

CONCLUSIONS

These results suggest that the quality of carbohydrates consumed is associated with the risk of obesity and hypertension. However, the cross-sectional design does not preclude reverse causality.

Successful targeting of the NRG1 pathway indicates novel treatment strategy for metastatic cancer

Background

NRG1 fusion-positive lung cancers have emerged as potentially actionable events in lung cancer, but clinical support is currently limited and no evidence of efficacy of this approach in cancers beyond lung has been shown.

Patients and methods

Here, we describe two patients with advanced cancers refractory to standard therapies. Patient 1 had lung adenocarcinoma and patient 2 cholangiocarcinoma. Whole-genome and transcriptome sequencing were carried out for these cases with select findings validated by fluorescence in situ hybridization.

Results

Both tumors were found to be positive for NRG1 gene fusions. In patient 1, an SDC4-NRG1 gene fusion was detected, similar gene fusions having been described in lung cancers previously. In patient 2, a novel ATP1B1-NRG1 gene fusion was detected. Cholangiocarcinoma is not a disease type in which NRG1 fusions had been described previously. Integrative genome analysis was used to assess the potential functional significance of the detected genomic events including the gene fusions, prioritizing therapeutic strategies targeting the HER-family of growth factor receptors. Both patients were treated with the pan HER-family kinase inhibitor afatinib and both displayed significant and durable response to treatment. Upon progression sites of disease were sequenced. The lack of obvious genomic events to describe the disease progression indicated that broad transcriptomic or epigenetic mechanisms could be attributed to the lack of prolonged response to afatinib.

Conclusion

These observations lend further support to the use of pan HER-tyrosine kinase inhibitors for the treatment of NRG1 fusion-positive in both cancers of lung and hepatocellular origin and indicate more broadly that cancers found to be NRG1 fusion-positive may benefit from such a clinical approach regardless of their site of origin.

Clinical trial information

Personalized Oncogenomics (POG) Program of British Columbia: Utilization of Genomic Analysis to Better Understand Tumour Heterogeneity and Evolution (NCT02155621).