Mei-Kang Yuan

The Risk of Cataract Associated With Repeated Head and Neck CT Studies: A Nationwide Population-Based Study

OBJECTIVE Medical radiation-induced cataracts, especially those resulting from head and neck CT studies, are an issue of concern. The current study aimed to determine the risk of cataract associated with repeated radiation exposure from head and neck CT. MATERIALS AND METHODS This study used information from a random sample of 2 million persons enrolled in the nationally representative Taiwan National Health Insurance Research Database. Exposed cases consisted of patients with head and neck tumor 10-50 years old who underwent at least one CT between 2000 and 2009. The nonexposed control group was composed of subjects who were never exposed to CT studies but who were matched by time of enrollment, age, sex, history of coronary artery disease, hypertension, and diabetes. RESULTS There were 2776 patients in the exposed group and 27,761 matched subjects in the nonexposed group. The exposed group had higher overall incidence of cataracts (0.97% vs 0.72%; adjusted hazard ratio [HR], 1.76; 95% CI, 1.18-2.63). Further stratifying the number of CT studies in the exposed group into one or two, three or four, and five or more revealed that cataract incidence increased gradually with increasing frequency of CT studies (0.79%, 0.93%, and 1.45%, respectively) (p=0.001, adjusted for trend). Radiation exposure due to repeated head and neck CT studies was independently associated with an increased risk of developing cataracts when the cumulative CT exposure frequency involved more than four studies (adjusted HR, 2.12; 95% CI, 1.09-4.14). CONCLUSION Repeated exposure to head and neck CT is significantly associated with increased risk of cataract.

Gefitinib-Related Interstitial Lung Disease in Taiwanese Patients With Non–Small-Cell Lung Cancer

BACKGROUND Gefitinib (Iressa; AstreZeneca, Wilmington, DE) is effective in the treatment of NSCLC, especially in the Asian population. However, ILD is usually a serious pulmonary adverse effect and almost leads to cessation of gefitinib treatment. In this study, we investigated the incidence, clinical features, and prognosis of gefitinib-related ILD in Taiwanese patients with NSCLC. PATIENTS AND METHODS This was a retrospective observational study conducted in 2 medical centers and a local teaching hospital. RESULTS A total of 1080 patients with NSCLC, who received at least 1 dose (250 mg per day) of gefitinib treatment, were enrolled. Of these, 42 patients were diagnosed with ILD. Twenty-five of the 42 patients were diagnosed with gefitinib-related ILD (incidence, 2.3%). The main manifestations of ILD included dyspnea, cough, and hypoxemia. Six of the 25 patients (24%) with gefitinib-related ILD required invasive mechanical ventilation and all patients were treated with steroids. Twenty-two patients (88%) discontinued gefitinib treatment without further rechallenge. Ten (40%) patients died directly from ILD and in-hospital mortality was 52%. Eleven patients received subsequent cytotoxic chemotherapy with a mean of 33.5 days after ILD events. Kaplan-Meier analysis demonstrated that gefitinib nonresponder and gefitinib use rather than first-line treatment were associated with poor prognosis when ILD developed during gefitinib treatment. CONCLUSION Taiwanese patients with NSCLC had a relatively high incidence of ILD during gefitinib treatment. Gefitinib-related ILD is usually life-threatening, especially in gefitinib nonresponders and gefitinib use rather than first-line treatment.

Bacterial pneumonia following acute ischemic stroke

Background: The most common serious complication following acute ischemic stroke is pneumonia, which may increase mortality and worsen clinical outcomes. The purpose of this study was to investigate the predictors of 30‐day mortality in patients with pneumonia following acute ischemic stroke. Methods: From June 2006 to May 2011, we retrospectively included 51 patients with pneumonia following acute ischemic stroke. We analyzed the clinical features, microbiologic data, and outcomes. Predictors of 30‐day mortality were investigated by univariate and multivariate analysis. Results: The acute ischemic strokes were caused by large‐artery atherosclerosis in 37 (72.5%) of the 51 patients. We found that the most common pathogen responsible for poststroke pneumonia was Klebsiella pneumoniae, followed by Pseudomonas aeruginosa and Escherichia coli. Ultimately, 12 patients died of progressive sepsis due to pneumonia after the acute ischemic stroke. The 30‐day mortality rate was 23.5%. In the univariate analysis, patients who died within 30 days had higher National Institutes of Health Stroke Scale scores, higher CURB‐65 scores, elevated instability of hemodynamic status, and lower Glasgow Coma Scale (GCS) scores. In Cox regression analysis, a GCS score of <9 on the day of pneumonia onset was only significant indicator for 30‐day mortality (hazard ratio, 6.72; 95% confidence interval, 2.12–21.30, p = 0.001). Conclusion: Pneumonia after acute ischemic stroke is a severe complication. Once stroke‐related pneumonia develops, neurologic assessment, CURB‐65 score, and shock can be used to predict the ultimate prognosis.

Health Effects of Medical Radiation on Cardiologists Who Perform Cardiac Catheterization

Background: We investigated the health effects of low‐dose radiation on cardiologists exposed to scattered radiation while performing cardiac catheterization (CC) in a hospital setting from 2003 to 2006. Methods: We performed a 4‐year retrospective study on 2, 292 medical doctors, using claims data from all contracted hospitals of the Bureau of National Health Insurance, Taiwan. We gathered statistical data regarding radiation‐related diseases using the International Classification of Diseases, 9th Revision, Clinical Modification record numbers of each doctor. Results: Of the 2,292 doctors evaluated, 1,721 were aged 35–50 years and the remaining 571 were aged 51–65 years. There were 892 cardiologists who performed CC (experimental group), and the majority of these (733/892, 82.17%) were aged 35–50 years. There were 1,400 medical doctors who performed no CC from 2003 to 2006 (control group). A total of 988 of these belonged to the 35–50 years age group and 412 to the 51–65 years group. In the 35–50 years group, the controls had significantly more medical visits for hematological and thyroid cancer (p <0.05), skin disease (p <0.001), and acute upper respiratory tract infection (p <0.001) compared with the experimental group. In contrast, cardiologists who performed catheterization had more cataracts compared with the control group, but this difference was not significant. Conclusion: Doctors who did not perform CC had more visits for radiation‐related diseases than those who performed catheterization. In the experimental group, cardiologists aged 35–50 years who were exposed to radiation during CC had more visits for cataracts than the control group. We recommend that radiation protection concepts be emphasized to cardiologists, and that hospital managers be obligated to upgrade angiography equipment because the newer models have less scattered radiation.

Risk factors in patients with AFB smear-positive sputum who receive inappropriate antituberculous treatment

Background Acid-fast bacilli (AFB) smear-positive sputum is usually an initial clue in the diagnosis of pulmonary tuberculosis (TB); however, the test is not disease-specific. Nontuberculous mycobacterium-related colonization or lung disease often has AFB smear-positive sputum results, and physicians may prescribe unnecessary antituberculous drugs for these patients. The aim of this study was to analyze the clinical characteristics of patients with AFB smear-positive sputum who received unnecessary anti-TB treatment. Methods and patients From January 2008 to July 2011, we retrospectively enrolled 97 patients with AFB smear-positive sputum who did not have pulmonary TB according to mycobacterial cultures and clinical judgment. We analyzed the clinical and radiographic features of the patients who received inappropriate and unnecessary anti-TB treatment. Preliminary analyses of chisquare and Fisher’s exact tests were applied to determine factors unlikely to be associated with the independent variables. The relationship between independent covariates was then analyzed using multivariate logistic regression. Results Of the 97 enrolled patients, 25 (25.8%) were diagnosed with pulmonary TB and prescribed anti-TB drugs (mostly a combination of isoniazid, rifampicin, ethambutol, and pyrazinamide). The other 72 (74.2%) patients were not initially diagnosed with pulmonary TB and were classified as the control group. Compared to the control group, the patients who received inappropriate anti-TB treatment had more chronic cough as presentation symptom and heavy AFB Ziehl–Neelsen staining in sputum (>10/100 fields, grading 2+ to 4+). There were no significant differences in the radiographic analysis between the two groups. Conclusion Among the patients with AFB smear-positive sputum that did not have pulmonary TB, chronic cough and heavy AFB staining (2+ to 4+) were risk factors for the inappropriate administration of unnecessary anti-TB treatment.

Both gefitinib and erlotinib induced drug-related interstitial lung disease in a patient with pulmonary adenocarcinoma

Treatment for non-small-cell lung cancer with gefitinib and erlotinib is efficacious. However, while many studies have reported on gefitinib-related interstitial lung disease (ILD), less published data are available regarding erlotinib-induced ILD. Here, we report a case of pulmonary adenocarcinoma who developed ILD due to gefitinib initially and erlotinib thereafter. The two episodes of ILD were treated successfully with the discontinuation of the tyrosine kinase inhibitors and high-dose intravenous corticosteroids.

Video-assisted thoracoscopic surgical decortication in the elderly with thoracic empyema: Five years' experience

Background Video‐assisted thoracoscopic surgery (VATS) with decortication is a major treatment for thoracic empyema in the fibropurulent stage. Compared to open thoracotomy, VATS decortication has similar efficacy but fewer postoperative complications in the treatment of thoracic empyema. The role of VATS decortication in the elderly had rarely been investigated. Methods From January 2006 to August 2011, we retrospectively enrolled 33 patients older than 65 years diagnosed as thoracic empyema and treated with VATS decortication. We analyzed the outcomes of this geriatric population, including surgical effectiveness, postoperative morbidity, and mortality. Results A total of 33 patients with mean age of 73.6 ± 7.1 years received VATS decortication for their empyema. Twenty‐one (63.6%) patients were male. Only one patient died of progressive sepsis, due to pulmonary infection 9 days after VATS decortication. The 30‐day mortality was 3% after the surgery. The major etiology (87.9%) of thoracic empyema was pneumonia. The main causes of postoperation morbidity included respiratory failure requiring mechanical ventilation for >7 days (15.2%) and septic shock (15.2%), followed by persistent air leakage for >7 days (9.1%). Twenty‐four (75%) of 32 patients had good re‐expansion of the affected lung 3 months after VATS decortication. Conclusion We concluded that VATS decortication in the treatment of thoracic empyema is effective in elderly patients. The major concerns of postoperative complications are respiratory failure and sepsis.

Mammography and the risk of thyroid and hematological cancers: a nationwide population-based study.

To investigate the association between thyroid cancer as well as the most radiosensitive hematological cancers and radiation exposure from mammography. This study used information from a random sample of two million persons enrolled in the nationally representative Taiwan National Health Insurance (NHI) Research Database. The exposed group was composed of women aged 18–65 who had undergone diagnostic mammography between 2000 and 2007. The nonexposed control group was composed of women in the NHI database who had never undergone diagnostic mammography. There were 25,362 women in the exposed group and 203,317 women in the nonexposed group. After adjusting for age and comorbidities, the patients who had been exposed to radiation from mammography did not have a significantly higher risk of developing thyroid cancer and hematological cancers (adjusted HR, 1.201; 95% CI, 0.813–1.774 for thyroid cancer and adjusted HR, 1.228; 95% CI, 0.838–1.800 for hematological cancers). The scattered radiation dose delivered by mammography should be cautiously handled, but no additional concerns about the risk of thyroid cancer developing malignancy should be emphasized.

The value of positron emission tomography in early detection of lung cancer in high‐risk population: a systematic review

Background:  Early detection trials with chest radiography and sputum cytology were ineffective in decreasing lung cancer mortality. The advent of low‐dose spiral chest computed tomography (LDCT) provided clinicians with a new tool that could be with early diagnosis; however, this also raised significant concerns regarding the systematic use of LDCT with its high false‐positive rate for benign nodules. At this time, there is limited information about the true role of PET (positron emission tomography) for early detection of lung cancer.

Imaging patterns and prognosis of patients with gefitinib-related interstitial lung disease.

PURPOSE We aimed to summarize the imaging findings of 25 patients with gefitinib-related interstitial lung disease (ILD), and identify the factors related to prognosis of gefitinib-related ILD in patients with non-small-cell-lung cancer. MATERIALS AND METHODS Diagnosis of gefitinib-induced ILD by at least two chest radiologists was based on a review and analysis of the chest radiography and CT findings plus clinical data in the medical records. All patients were diagnosed with Stage III - IV non-small-cell carcinoma (adenocarcinoma (n = 24), bronchioalveolar cell carcinoma (n = 1)) and essential clinical data such as gefitinib as first-line use and survival status were recorded and analyzed to determine whether these were prognosis predictors. The imaging findings were classified into four patterns according to the previous largest study in Japan. RESULTS The 25 chest radiographs were classified as Pattern A (n = 8), Pattern B (n = 3), Pattern C (n = 6), and pattern D (n = 8). Likewise the 23 CT images were classified as pattern A (n = 8; 34.8%), B (n = 3; 13%), C (n = 5; 21.7%), and D (n = 7; 30.4%). The mortality rate was significantly higher in patients with pattern D than in patients with the other patterns. Pattern D imaging findings were also significantly correlated with non first-line use of gefitinib (p = 0.007). CONCLUSIONS We found an increase in mortality rate in patients with gefitinib associated ILD/pattern D compared to other radiological patterns. Familiarity with these imaging patterns can facilitate early and accurate diagnosis and help physicians gauge clinical prognosis of gefitinib-related ILD.