# A Spatial Study of Head and Neck Cancer Incidence Rate in Fars Province (the South of Iran): 2007-2020

## TL;DR

This study maps the incidence of head and neck cancers in Fars province, Iran, finding higher rates in northern areas, possibly due to lifestyle and environmental factors.

## Contribution

The study introduces a Bayesian spatiotemporal model to analyze HNC incidence rates and their spatial distribution in Fars province.

## Key findings

- The highest relative risks for HNC and SCC were found in Shiraz, the capital of Fars province.
- Gerash County had the lowest relative risks for HNC and SCC.
- HNC incidence rates increased over time, while SCC rates decreased.

## Abstract

Head and neck cancers (HNCs) are among the top ten most common cancers globally. There is a clear geographical bias in the prevalence of HNCs. More than two-thirds of HNC
cases worldwide occur in low- and middle-income countries. Due to the high prevalence of HNCs in Fars province.

The purpose of this study was to assess the spatial pattern of HNC incidence rates by modeling both the effects of spatial dependence between neighboring regions and risk factors in a Bayesian Poisson model (BYM).

In this cross sectional study, from the Center of Cancer Registry in Fars province, data was collected from 1,821 patients diagnosed with HNC. The effects of spatial structure
were modeled in a Bayesian spatiotemporal hierarchical model to determine the relative risk and trend of HNC incidence rates. The maps were created geographical variations of HNCs
incidence across the 29 counties of the province with classical Standardized Incidence Rate (SIR), BYM model, and spatiotemporal model.

The highest crude incidence rates were 0.55 and 0.16 cases per 1,000-person population for HNC and squamous cell carcinoma (SCC), respectively. Spatially, the highest
relative risks for HNC and SCC were estimated at 1.36 and 1.34, respectively, in the county of Shiraz, the capital of Fars province. The lowest relative risks for HNC
and SCC were estimated at 0.39 and 0.46 per 1,000 persons, respectively, in Gerash County in southern Fars. The findings showed an increasing trend in the HNC incidence rate and a decreasing trend in SCC incidence in this province.

Spatial analysis of HNCs revealed a high incidence rate in the northern and northeastern parts of Fars province, which may be attributed to the effects of lifestyle factors and certain pollutants in the region's cold air.