Burden, trends, projections, and spatial patterns of lip and oral cavity cancer in Iran: a time-series analysis from 1990 to 2040.

Background: Lip and oral cavity cancer (LOCC) is a significant public health concern worldwide. This study investigated the long-term trends in the LOCC burden in Iran from 1990 to 2021.

Methods: We analyzed LOCC burden in Iran from 1990 to 2021 using the Global Burden of Disease (GBD) 2021 dataset, focusing on age-standardized disability-adjusted life years (ASDR), mortality rates (ASMR), and incidence rates (ASIR) stratified by sex and province. Joinpoint regression analysis was used to identify temporal trends, and the annual percent change (APC) and average APC (AAPC) were calculated. Future projections up to 2040 were generated using a hybrid forecasting model (ARIMA, ETS, and neural networks). Spatial analysis detected hotspot and coldspot regions in 1990 and 2021.

Results: We observed a significant increase in the LOCC burden across all three indicators (disability-adjusted life years [DALY], ASMR, and ASIR) from 1990 to 2021. Joinpoint analysis revealed significant temporal trends, with an overall upward trajectory in the AAPC for both sexes combined and separately. Specifically, the overall AAPC for the ASDR was 0.34% (95% confidence interval [CI]: 0.26,0.39) for both sexes, 0.40% (95% CI: 0.32,0.45) for females, and 0.35% (95% CI: 0.27,0.42) for males. For the ASMR, the overall AAPC was 0.41% (95% CI: 0.34,0.46), 0.54% (95% CI: 0.48,0.58) for females, and 0.36% (95% CI: 0.29,0.42) for males. Similarly, the overall AAPC for ASIR was 1.33% (95% CI: 1.24,1.40), 1.51% (95% CI: 1.43,1.59) for females, and 1.26% (95% CI: 1.17,1.33) for males. Geographic variations were evident, with most provinces exhibiting increasing ASDR and ASMR, while ASIR displayed a consistent upward trend across all provinces. Notably, females showed a slightly more pronounced increase in ASDR, ASMR, and ASIR compared to males. Projections indicate a declining trend in DALYs, a fluctuating but stable mortality rate, and a continuous rise in incidence by 2040. Spatial analysis indicated no significant spatial autocorrelation at the national level in both 1990 and 2021.

Conclusion: Our findings highlight a rising burden of LOCC in Iran, with future projections indicating a growing incidence rate. Targeted public health interventions addressing regional disparities and risk factors are crucial. Sex-specific and region-specific policies, along with early detection strategies, are essential to mitigate the disease burden.