The effect of time changes in diagnosing lung cancer type on its recorded distribution, with particular reference to adenocarcinoma

Tar level of cigarettes smoked and risk of smoking-related diseases

BACKGROUND

Opinions differ on the relationship between tar level and risk of smoking-related disease. However, except for lung cancer, few reviews have evaluated the epidemiological evidence. Here the relationship of tar level to risk of the four main smoking-related diseases is considered.

METHODS

Papers comparing risk of lung cancer, COPD, heart disease or stroke in smokers of lower and higher tar yield cigarettes were identified from reviews and searches, relative risk estimates being extracted comparing the lowest and highest tar groups. Meta-analyses investigated heterogeneity by various study characteristics.

RESULTS

Twenty-six studies were identified, nine of prospective design and 17 case-control. Two studies grouped cigarettes by nicotine rather than tar. Seventeen studies gave results for lung cancer, 16 for heart disease, five for stroke and four for COPD. Preferring relative risks adjusted for daily amount smoked, where adjusted and unadjusted estimates were available, combined estimates for lowest versus highest tar (or nicotine) groups were 0.78 (95% confidence interval 0.70-0.88) for lung cancer, 0.86 (0.81-0.91) for heart disease, 0.77 (0.62-0.95) for stroke and 0.81 (0.65-1.02) for COPD. Lower risks were generally evident in subgroups by publication period, gender, study design, location and extent of confounder adjustment. Estimates were similar preferring data unadjusted for amount smoked or excluding nicotine-based estimates.

CONCLUSIONS

Despite evidence that smokers substantially compensate for reduced cigarette yields, the results clearly show lower risks in lower tar smokers. Limitations of the evidence are discussed, but seem unlikely to affect this conclusion.

[Trends in incidence of lung cancer according to histological subtype among men and women in Germany : Analysis of cancer registry data with the application of multiple imputation techniques]

BACKGROUND

Lung cancer can be described by histological subtype, of which small cell, squamous cell and adenocarcinoma are the most common. International data show that adenocarcinoma is becoming the dominant histological subtype of lung cancer although the relative risk due to smoking has been found to be smaller than that for other histological subtypes.

OBJECTIVE

The aim of the analysis was to describe the time trends in incidence of lung cancer among women and men in Germany according to histological subtype.

MATERIALS AND METHODS

All lung cancer cases (ICD-10 C33-C34) newly diagnosed between 2003 and 2012 and collected by the epidemiologic cancer registries of the German federal states with average completeness of registration of at least 90% were considered and grouped into histologic subtypes. If data on tumor histology were not microscopically verified or unspecific, multiple imputation techniques were applied to estimate the histologic subtype.

RESULTS

Among women age-standardized lung cancer rates increased considerably between 2003 and 2012 (annual percent change APC = 2.7%), mostly driven by a rising adenocarcinoma incidence (APC = 4.7%). Among men overall lung cancer rates decreased during the same time (APC = -1.7%). Still, a slight increase in adenocarcinoma incidence was also observed in men (APC = 1.0%).

CONCLUSION

The rising incidence of adenocarcinoma of the lung is alarming. The cancer registry data do not allow risk factor analysis. In the international discussion, the introduction of filter cigarettes as well as the changing composition of cigarettes has been hypothesized as being responsible. Further epidemiologic studies are strongly needed.

Reversal effect of adenovirus-mediated human interleukin 24 transfection on the cisplatin resistance of A549/DDP lung cancer cells

Interleukin-24 (IL-24) is a tumor-suppressor gene that has been documented in human melanoma cells. IL-24 has marked antitumor activities on various types of human cancer, but its underlying mechanism remains unclear. In the present, we investigated the effects of human IL-24 (hIL-24) on the chemotherapy resistance of lung cancer cells. The cisplatin (DDP)-resistant lung carcinoma cell line A549/DDP was subjected to adenovirus-mediated transfection with the human IL-24 gene (Ad-hIL-24). The growth-inhibitory and apoptotic effects of Ad-hIL-24 on A549/DDP cells were observed, and the expression levels of AKT, phosphorylated-AKT (p-AKT) and P-glycoprotein (P-gp) were detected. Ad-hIL-24 significantly decreased the levels of p-AKT and P-gp, and effectively inhibited A549/DDP cell growth. Furthermore, A549/DDP cells exhibited a significantly increased rate of apoptosis, as well as G2/M-phase arrest, following transfection with Ad-hIL-24, and these effects were increased in cells treated with Ad-IL-24 combined with DDP when compared with those treated with Ad-hIL-24 or DDP alone. These results suggest that hIL-24 can reverse the DDP resistance of lung cancer cells, and that the associated mechanism involves the induction of apoptosis and G2/M-phase arrest through the phosphoinositide3-kinase (PI3K)/AKT signaling pathway, as well as a decrease in drug resistance through P-gp expression.