Trends in Lung Cancer Incidence in Delhi, India 1988-2012: Age-Period-Cohort and Joinpoint Analyses

Document Type: Research Articles

Authors

1 Delhi Cancer Registry, New Delhi, India.

2 Department of Radiation Oncology, Dr. B.R.Ambedkar Institute Rotary Cancer Hospital, All India Institute of Medical Sciences, New Delhi, India.

3 Department of Surgical Oncology, Institute Rotary Cancer Hospital (IRCH), All India Institute of Medical Sciences, New Delhi, India.

Abstract

Introduction: Lung cancer (LC) has been one of the most commonly diagnosed cancers worldwide, both in terms
of new cases and mortality. Exponential growth of economic and industrial activities in recent decades in the Delhi
urban area may have increased the incidence of LC. The primary objective of this study was to evaluate the time trend
according to gender. Method: LC incidence data over 25 years were obtained from the population based urban Delhi
cancer registry. Joinpoint regression analysis was applied for evaluating the time trend of age-standardized incidence
rates. The age-period-cohort (APC) model was employed using Poisson distribution with a log link function and the
intrinsic estimator method. Results: During the 25 years, 13,489 male and 3,259 female LC cases were registered,
accounting for 9.78% of male and 2.53% of female total cancer cases. Joinpoint regression analysis revealed that LC
incidence in males continued to increase during the entire period, a sharp acceleration being observed starting from
2009. In females the LC incidence rate remained a plateau during 1988-2002 and thereafter increased. The cumulative
risks for 1988-2012 were 1.79% and 0.45%. The full APC (IE) model showed best fit for an age-period-cohort effect
on LC incidence, with significant increase with age peaking at 70-74 years in males and 65-69 years in females. A
rising period effect was observed after adjusting for age and cohort effects in both genders and a declining cohort effect
was identified after controlling for age and period effects. Conclusion: The incidence of LC in urban Delhi showed
increasing trend from 1988-2012. Known factors such as environmental conservation, tobacco control, physical activity
awareness and medical security should be implemented more vigorously over the long term in our population.

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