Abstract
INTRODUCTION: Cancer incidences are rising worldwide, and India ranked third globally in cancer incidence as of 2020, according to estimates from GLOBOCAN. The three components that contributed to changes in cancer incidence include cancer-related risk factors, population size, and population structure. The present study aim is to derive the contribution of these factors to cancer incidence and to evaluate their trend from 1991 to 2015. METHODS: The Data were extracted from the Delhi population-based cancer registry published reports. This longstanding registry covers nearly 100% of the Delhi population. The secular trends of cancer incidence from 1991-2015 were assessed for all sites combined as well as top-five cancer sites among males and females. Joinpoint regression and Riskdiff software were performed to assess the trend among the components of cancer incidence change. RESULTS: Both males and females exhibited nearly equal age-standardised incidence rates over 25 years. Albeit, an overall trend in age-standardised rate was not significant for both sexes (0.68% for males and -0.16% for females) when considering all cancer sites combined. Lung, prostate, oral, and gallbladder cancer exhibits a significant rising trend in the age-standardised rates in males while in females only breast and endometrial cancer showed a rising trend. The cancer counts surged by 252% in males and 208.5% in females from 1991 to 2015. The population size component contributed a 180% increase in males and a 170% increase in females, respectively. The site-specific risk changes were more than 100% for the prostate, oral, and gallbladder cancers in males and endometrial cancer in females. The population structure (aging) contributed to rising cancer incidence varying from 35% to 60% in both genders. CONCLUSION: A significant contribution to new cancer cases was observed due to a demographical shift in both population size and structure, in addition to plausible cancer-specific risk factors. This transformation could surge a potential burden on the Delhi healthcare system. Persistent endeavours are essential to expand and enhance the existing cancer care infrastructure to meet the rising demand driven by aging and population growth. Implementing a stringent population policy can help to mitigate the impact of population growth on cancer incidence.