Abstract 1191: Divergent trends in lung cancer incidence by histologic subtype in Philippines, 2003-2012: A population-based study
Authors: Cambia Jansen Marcos , Oh Jin Kyoung , Pasaol Jayson Cagadas 
Published: September 2020

Introduction. Lung cancer (LC) is the leading cause of cancer incidence among men and third most frequent case in women in the Philippines. LC incidence rates, overall and by histologic subtype, vary substantially by sex and smoking prevalence. The study aimed to analyze time trends in LC incidence in the Philippines over the 10-year period. There is no published report regarding trends of LC incidence by histologic subtype in the Philippines. Herein, we provide model-based estimates of limited time LC cases by histologic subtype from year 2003-2012.

Methodology. Data for calculating LC incidence rates in 2003-2012 were obtained from the nationwide population-based Department of Health- Rizal Cancer Registry. Joinpoint regression was used to analyze trends and estimate annual percentage change (APC) with 95% confidence intervals (CI) on LC incidence by histologic subtype, time- period, sex, and geographical location, calculated incidence counts, rates per 100,000 person-years. 2000 - 2015 population used in calculating ASR of LC incidence where taken from Philippines Statistics Authority (PSA), and each annual population from 2003 - 2012 where estimated using exponential function by extrapolation.

Results. LC incidence shows increasing average annual rates in the past 10 years, observed rate overall (19.5), male (27.0) and female (12.1). Among LC specified histologic subtype, adenocarcinoma (ADC) contributes highest rate, in men (9.8) and women (5.5), followed by squamous cell carcinoma (SQCC), in men (3.6) and women (0.6). Incidence trend declines to both sexes in 2007, and increases thereafter, in men (APC: 13.7, 95% CI: -8.5; 41.3) and women (APC: 14.8, 95% CI: -10.0; 47.4). The highest increase in average annual percentage change (AAPC) among specified LC histologic subtype were observe to ADC, in men (APC: 6.5, 95% CI: -2.2; 16.1) and women (APC: 8.5, 95% CI: -1.4; 19.5). Along with SQCC to women's cohort were also remark high AAPC (APC: 6.7, 95% CI: -4.4; 19.0). From cohort 2003- 2007 carcinoma not otherwise specified which has the foremost number of cases among non-specified histologic subtype eventually decreased by half folds from cohort 2008-2012. In contrast, malignant neoplasm increase doubled in rate from each mentioned year-cohorts.

Conclusion. The study revealed divergent LC trends by gender and histologic subtype, which were generally consistent from 2003-2012. Among LC histological subtypes, large increase in incidence was observed for ADC, which both genders showed an increasing trend for 10-year period. LC will always remain a serious public health issue in the Philippines such implementation of National Tobacco Control Policy should be prioritized in preventing smoking initiation and promoting smoking cessation, particularly among men.

Citation Format: Jansen Marcos Cambia, Jin Kyoung Oh, Jayson Cagadas Pasaol. Divergent trends in lung cancer incidence by histologic subtype in Philippines, 2003-2012: A population-based study [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 1191.