Temporal Trends and Geographic Patterns of Lung Cancer Incidence by Histology in Thailand, 1990 to 2014

Purpose Lung cancer is one of the most common cancers worldwide and in Thailand. We characterize and forecast region-specific patterns of lung cancer incidence by histology and sex. Methods We analyzed lung cancer incidence trends in Thailand by histology (adenocarcinoma [AdC]; squamous cell carcinoma [SCC]; and large-cell, small-cell, and other carcinomas) from 1990 to 2014 in four cancer registries in three regions (north, Chiang Mai Province and Lampang Province; northeast: Khon Kaen Province; south: Songkhla Province). Annual percent change (APC) was calculated to quantify the incidence rate trends using joinpoint regression. Age-period-cohort models were used to examine the temporal trends of AdC and SCC by age, calendar year, and birth cohort. We projected the incidence of AdC and SCC up to 2030 using three independent approaches: joinpoint, age-period-cohort, and Nordpred models. Results AdC incidence significantly increased from 1990 to 2012 in Chiang Mai males (APC, 1.3%), Songkhla males from 2004 to 2014 (APC, 2.5%), Songkhla females from 1990 to 2014 (APC, 5.9%), and Khon Kaen females from 2005 to 2014 (APC, 3.1%). Conversely, SCC incidence significantly decreased from 1990 to 2012 in Chiang Mai males and females (APC, -1.2% and -4.8%, respectively), Lampang males and females from 1993 to 2014 (APC, -5.4% and -5.2%, respectively), and Songkhla females from 1990 to 2014 (APC, -2.1%). In general, trends of AdC and SCC correlated more with birth cohort than with calendar year. Three projection models suggested that incidence rates of AdC in Songkhla may continue to increase until 2030. Conclusion Temporal trends of lung cancer by histology varied among regions in Thailand. Reduction of lung cancer incidence in Thailand likely will require prevention strategies tailored to each specific region.