Philip Eng

Never-Smokers With Lung Cancer: Epidemiologic Evidence of a Distinct Disease Entity

PURPOSE Tobacco smoke is a definite causative agent for lung cancer. It is increasingly being recognized that never-smokers can be afflicted with non-small-cell lung cancer (NSCLC). We aim to assess survival differences between smokers and never-smokers with NSCLC. PATIENTS AND METHODS We analyzed 975 NSCLC patients who presented from January 1999 to December 2002. Clinical characteristics among current-, former- and never-smokers were tested using chi2 or Kruskal-Wallis test. The hazard ratio (HR) for death and its 95% CI were calculated by Cox regression. RESULTS Of 975 patients, 59 had no smoking history and 33 had no quit time recorded. Of 883 patients analyzed, 286 patients (32.4%) were never-smokers. One hundred ninety-six never-smokers (68.5%) were females compared with 12% among current- and 13% among former-smokers (P < .001). There was a significant difference in histologic subtype between never-smokers and smokers: 69.9% with adenocarcinoma versus 39.9% (current-smokers) versus 47.3% (former-smokers); 5.9% with squamous cell carcinoma versus 35.7% (current-smokers) versus 28% (former-smokers; P < .001). Smokers had significantly poorer performance status (P = .002) and higher median age at diagnosis (P < .001) while more never-smokers presented with advanced disease (P = .002). Eight hundred and five patients (82.6%) died by May 30, 2005. The HR for smokers was significantly higher on both univariate and multivariate analysis (HR, 1.297; 95% CI, 1.040 to 1.619). CONCLUSION Never-smokers comprised a high proportion of NSCLC patients in Singapore. Definite epidemiologic differences exist between never-smokers and smokers. Differences in survival outcome further suggest that the biology underlying the pathogenesis and behavior of the disease may be different for never-smokers.

Frequent hospital readmissions for acute exacerbation of COPD and their associated factors

Objective:  The factors that determine frequent hospital readmissions for acute exacerbations of COPD (AECOPD) are poorly understood. The aim of this study was to ascertain rates of re‐hospitalizations for AECOPD patients and evaluate factors associated with frequent readmissions for acute exacerbations.

Diet, reproductive factors and lung cancer risk among Chinese women in Singapore: evidence for a protective effect of soy in nonsmokers.

The factors associated with risk of lung cancer among nonsmokers have not been fully elucidated, but dietary factors have consistently been shown to play a role. Chinese women are unique in having a high incidence of lung cancer despite a low smoking prevalence. This population is also known to have a high intake of soy, a dietary source of phytoestrogens. We conducted a hospital‐based case‐control study among Singapore Chinese women, comprising 303 cases and 765 age‐matched controls, of whom 176 cases and 663 controls were lifetime nonsmokers. Data on demographic background, reproductive factors and dietary intake of fruit, vegetables and soy foods were obtained by in‐person interview. We observed an inverse association between intake of total, cruciferous and non‐cruciferous vegetables and risk of lung cancer among smokers. Although smokers in the highest tertile of fruit intake also had a lower risk, this was not statistically significant. Higher intake of soy foods significantly reduced risk of lung cancer among lifetime nonsmokers, but not among smokers. When soy isoflavonoid intake in mg/week was computed based on frequency and portion size of intake of eight common local soy foods, the adjusted OR among nonsmokers for the highest tertile compared to the lowest was 0.56, 95% CI 0.37–0.85 (p for trend <0.01). Fruit intake was also significantly associated with reduced lung cancer risk among nonsmokers, but the effect was not significant after adjustment for soy intake. On the other hand, soy intake remained an independent predictor of risk after controlling for fruit intake. Reproductive effects were also primarily confined to lifetime nonsmokers, among whom having 3 or more livebirths (adjusted OR 0.65, 0.44–0.96) and a menstrual cycle length of more than 30 days (OR 0.46, 0.25–0.84) accorded a significantly reduced risk of lung cancer. Place of birth was significantly associated with risk among nonsmokers (OR 2.6, 1.7–3.9 for China‐born vs. local born) but not among smokers. When analysis was restricted to nonsmokers with adenocarcinomas, the dietary effects were consistent or enhanced. On stepwise regression, soy intake and cycle length emerged as the independent dietary and reproductive predictors of lung cancer risk in nonsmokers. These findings are consistent with other evidence suggesting an involvement of estrogen‐related pathways in lung cancer among non‐smoking women.

Negative pressure pulmonary oedema in the medical intensive care unit.

ObjectiveNegative pressure pulmonary oedema (NPPE) occurring in the medical intensive care unit (MICU) is an uncommon, probably under-diagnosed, but life-threatening condition.DesignRetrospective data collection.SettingMedical intensive care unit in a 1,500–bedded tertiary care hospital.Patients and participantsFive patients were diagnosed between January 1998 and January 2002.InterventionsNone.Measurements and resultsFive patients were diagnosed to have NPPE from different aetiologies. These were acute epiglottitis, post-stenting of right bronchus intermedius stenosis, strangulation, compression from a goitre and one patient developed diffuse alveolar haemorrhage after biting the endotracheal tube during recovery from anaesthesia. All patients responded rapidly to supplemental oxygen, positive pressure ventilation and correction of underlying aetiologies. Pulmonary oedema resolved rapidly.ConclusionsThere is a large spectrum of aetiologies causing NPPE in the medical intensive care unit.

Insights, attitudes and perceptions about asthma and its treatment: Findings from a multinational survey of patients from 8 Asia-Pacific countries and Hong Kong

The Asthma Insight and Management (AIM) survey was conducted in North America, Europe, the Asia‐Pacific region and Latin America to characterize patients’ insights, attitudes and perceptions about their asthma and its treatment. We report findings from the Asia‐Pacific survey.

Lung Cancer in Chinese Women: Evidence for an Interaction between Tobacco Smoking and Exposure to Inhalants in the Indoor Environment

Background Epidemiologic data suggest that Chinese women have a high incidence of lung cancer in relation to their smoking prevalence. In addition to active tobacco smoke exposure, other sources of fumes and airborne particles in the indoor environment, such as cooking and burning of incense and mosquito coils, have been considered potential risk factors for lung cancer. Objectives We used a case–control study to explore effects of inhalants from combustion sources common in the domestic environment on lung cancer and their modification by active tobacco smoking. Methods We analyzed 703 primary lung cancer cases and 1,578 controls. Data on demographic background and relevant exposures were obtained by face-to-face interviews in the hospital. Results We observed a positive relationship with daily exposure to incense or mosquito coils and to cooking fumes only among smokers, and no association among lifetime nonsmokers. Interactions between smoking and frequency of cooking, or exposure to incense or mosquito coils were statistically significant and consistent with synergistic effects on lung cancer. The odds ratio (OR) comparing smokers without daily incense or mosquito coil exposure with nonsmokers without daily exposure was 2.80 [95% confidence interval (CI), 1.86–4.21], whereas the OR comparing smokers with daily exposure to the same referent group was 4.61 (95% CI, 3.41–6.24). In contrast, daily exposure to incense or mosquito coils was not associated with lung cancer among nonsmokers (OR = 0.91; 95% CI, 0.72–1.16). We observed the same pattern of associations for smokers without (OR = 2.31; 95% CI, 1.52–3.51) and with (OR = 4.50; 95% CI, 3.21–6.30) daily cooking exposure compared with nonsmokers, with no evidence of an association with daily cooking exposure among nonsmokers. Conclusion Our results suggest that active tobacco smoking not only is an important risk factor for development of lung cancer, but also may cause smokers to be more susceptible to the risk-enhancing effects of other inhalants.

Insights, attitudes and perceptions about asthma and its treatment

The Asthma Insight and Management (AIM) survey was conducted in North America, Europe, the Asia‐Pacific region and Latin America to characterize patients’ insights, attitudes and perceptions about their asthma and its treatment. We report findings from the Asia‐Pacific survey.

Positron emission tomography with CT in the evaluation of non-small cell lung cancer in populations with a high prevalence of tuberculosis.

Objective and background:  To determine the utility of positron emission tomography with CT (PET‐CT) in the evaluation of non‐small cell lung cancer (NSCLC) in an Asian context where tuberculosis rates are moderately high.

Survival among Chinese women with lung cancer in Singapore: a comparison by stage, histology and smoking status.

Lung cancer generally carries a poor prognosis and the determinants of survival have been of interest. However, survival estimates in Asian populations are scarce. This study describes survival rates and their determinants in Singapore Chinese women, a primarily non-smoking population. Three hundred and twenty-six Chinese women, diagnosed with primary lung carcinoma in three major hospitals in Singapore between April 1996 and December 1998, were followed up till 31 December 2000. The Kaplan-Meier method was used for survival analysis. Two hundred and eighty (85.7%) died from the disease during follow-up. The median survival time was 0.7 years and the three-year survival was 15.8%. These survival rates are similar to those of Western populations, and they provide a basis for examining trends over time. Age at diagnosis was an independent prognostic factor [adjusted hazard ratio (relative risk) 1.4, 95% confidence intervals (CI) 1.1-1.9 for women above 65 years relative to younger women]. Most (70.5%) tumours were stage III/IV at diagnosis. Three-year survival ranged from 72% among patients with stage I tumours to 7% for stage IV tumours. Overall, there was no survival difference among different histological types in all stages combined. When limited to stages I and II cancers, adenocarcinomas were associated with a better outcome relative to other histological subtypes combined (adjusted relative risk 0.4, 95% CI 0.1-1.0). Smoking was an independent risk factor (adjusted relative risk 1.3, 95% CI 1.0-1.8). Nevertheless, non-smokers comprised 57.4% of this series, highlighting the importance of increased awareness among health professionals and the public that lung cancer is not only a disease of smokers. The high proportion of late-stage tumours in this study and the impact of disease stage on outcome underline the importance of early detection in improving survival of lung cancer.

Female Reproductive Factors, Gene Polymorphisms in the Estrogen Metabolism Pathway, and Risk of Lung Cancer in Chinese Women

The authors examined relations between reproductive factors and 5 estrogen pathway gene polymorphisms (CYP17 rs743572, CYP19A1 rs10046, ERβ rs1256049, ERβ rs4986938, and COMT rs4680) among 702 Singapore Chinese female lung cancer cases and 1,578 hospital controls, of whom 433 cases (61.7%) and 1,375 controls (87.1%) were never smokers. Parity (per child, odds ratio (OR) = 0.92, 95% confidence interval (CI): 0.87, 0.97) and menstrual cycle length (for ≥30 days vs. <30 days, OR = 0.50, 95% CI: 0.32, 0.80) were inversely associated with lung cancer in never smokers, while age at first birth (for ages 21-25, 26-30, and ≥31 years vs. ≤20 years, ORs were 1.54, 2.17, and 1.30, respectively), age at menopause (for ages 49-51 and ≥52 years vs. ≤48 years, ORs were 1.37 and 1.59; P(trend) = 0.003), and reproductive period (for 31-33, 34-36, 37-39, and ≥40 years vs. ≤30 years, ORs were 1.06, 1.25, 1.45, and 1.47; P(trend) = 0.026) were positively associated. Among smokers, parity was inversely associated with lung cancer, but there was no association with other reproductive factors. The COMT rs4680 A allele was positively associated with lung cancer in never smokers (for G/A or A/A vs. G/G, OR = 1.46, 95% CI: 1.12, 1.90) but not in ever smokers. No associations were seen with other polymorphisms. These results support a risk-enhancing role of estrogens in lung carcinogenesis among never smokers.