Risk assessment and prediction for lung cancer among Hong Kong Chinese men.

OBJECTIVE: Most of the previous risk prediction models for lung cancer were developed from smokers, with discriminatory power ranging from 0.57 to 0.72. We constructed an individual risk prediction model for lung cancer among the male general population of Hong Kong. METHODS: Epidemiological data of 1,069 histology confirmed male lung cancer cases and 1,208 community controls were included in this analysis. Residential radon exposure was retrospectively reconstructed based on individual lifetime residential information. Multivariable logistic regression with repeated cross-validation method was used to select optimal risk predictors for each prediction model for different smoking strata. Individual absolute risk for lung cancer was estimated by Gail model. Receiver-operator characteristic curves, area under the curve (AUC) and confusion matrix were evaluated to demonstrate the model performance and ability to differentiate cases from non-cases. RESULTS: Smoking and smoking cessation, education, lung disease history, family history of cancer, residential radon exposure, dietary habits, carcinogens exposure, mask use and dust control in workplace were selected as the risk predictors for lung cancer. The AUC of estimated absolute risk for all lung cancers was 0.735 (95% CI: 0.714-0.756). Using 2.83% as the cutoff point of absolute risk, the predictive accuracy, positive predictive value and negative predictive value were 0.715, 0.818 and 0.674, respectively. CONCLUSION: We developed a risk prediction model with moderate discrimination for lung cancer among Hong Kong males. External validation in other populations is warranted for this model in future studies.

Definitive radiotherapy for early stage glottic cancer by 6 MV photons.

PURPOSE: To evaluate the clinical outcome of early glottic cancer (GC) treated by primary radiotherapy (RT) with 6 MV photons. METHODS AND MATERIALS: We retrospectively reviewed the medical records of 695 consecutive patients with T1N0 and T2N0 GC treated between 1983 and 2005 by RT in our institution. Clinical outcome in terms of local control (LC), overall survival (OS) and cause- specific survival (CSS) rate were evaluated. RESULTS: The median follow-up time was 10.5 years. The 10-year actuarial LC rates were as follows: T1A, 91%; T1B, 87%; T2, 77%. The 10-year OS were as follows: T1, 74.2%; T2, 70.7%. The 10-year CSS were as follows: T1, 97.7%; T2, 97.1%.Poorly differentiated histology and tumor biologically effective dose<65 Gy15 were adverse factors in both LC of T1 and T2 disease. Involvement of anterior commissure was an adverse factor in both LC and CSS of T1 disease. Subglottic extension was associated with poor LC in T2 disease whereas hemoglobin <13.0 was associated with poor LC and CSS of T2 disease. CONCLUSION: Primary RT remains an option among the various standard treatments for early GC. Clinical treatment outcome by 6MV photons is similar and comparable to historic data of Cobalt-60 and 2 MV photons.

Mesothelioma and lung cancer mortality: a historical cohort study among asbestosis workers in Hong Kong.

OBJECTIVES: To investigate the mortality pattern among a cohort of workers with asbestosis in Hong Kong, with special emphases on mesothelioma and lung cancer. METHODS: All 124 male workers with confirmed asbestosis in Hong Kong during 1981-2008 were followed up to December 31, 2008 to ascertain the vital status and causes of death. Standardized mortality ratio (SMR) for each underlying cause of death was calculated by using person-year method. Axelson's indirect method was applied to adjust for the potential confounding effect of cigarette smoking. RESULTS: A total of 86 deaths were observed after 432.8 person-years of observations. The SMR for overall mortality (6.06, 95% CI: 4.90-7.51) increased significantly. The elevated risk of deaths from all cancers (7.53, 95% CI: 5.38-10.25) was mainly resulted from a significantly excess risk from lung cancer (SMR=7.91, 95% CI: 4.32-13.29, 14 deaths) and mesothelioma (SMR=6013.63, 95% CI: 3505.95-9621.81, 17 deaths). The SMR for lung cancer retained statistically significant after adjustment of smoking. An increased smoking adjusted SMR was also suggested for all heart diseases (2.32, 95% CI: 0.93-4.79, 7 deaths) and acute myocardial infarction (3.10, 95% CI: 0.84-7.94, 4 deaths), though the statistical significance was borderline. We found a positive association with net years of exposure to asbestos for mesothelioma and lung cancer. CONCLUSIONS: Our study provided further evidence on the carcinogenesis of asbestos/asbestosis with the risk of deaths from lung cancer and mesothelioma. This study also provided a preliminary support for a possible link between asbestosis and heart disease, but power is limited.