Spatiotemporal mapping of cervical cancer incidence highlights need for targeted prevention in Songkhla province, Thailand

Abstract

Background: The national cervical cancer screening program in Thailand has been successful in reducing overall burden from this disease. However, evaluation on spatial and temporal scales is needed to assess the efficacy of this program in smaller regions. Here, we geographically assess incidence in a province with a uniquely heterogeneous distribution of lifestyle factors associated with religiosity.

Methods: Cervical cancer cases were extracted from the provincial cancer registry from 1989 to 2013. Age-adjusted incidence rates were calculated using population statistics from the census bureau and adjusted to the Segi world standard population. Bayesian hierarchical modelling was employed to spatiotemporally map cervical cancer incidence trends in Songkhla province in 5-year period.

Results: Overall, the incidence of cervical cancer decreased in Songkhla province. The three districts with a Muslim population of greater than 70% had consistently lower cervical cancer rates from 1989 to 2013 compared with the rest of the predominantly Buddhist districts. Hotspots of incidence were identified in Sadao, Hat Yai and the juncture of Mueang Songkhla and Singhanakhon in each 5-year period.

Conclusions: Distinct cervical cancer incidence trends by religion over time indicate differences in sexual habits, lifestyle and religion-associated culture between Muslims and Buddhists, and suggest divergent risk factor profiles for these groups. The high incidence rates in Sadao and Hat Yai is likely explained by the main road to Malaysia, which runs across these two areas and has frequent commercial sex trade. Female sex workers should be targeted as a vulnerable population for screening efforts to address this continuing burden of cervical cancer.

Keywords: Cancer; Thailand; cervical screening; mapping; prevention; vulnerable populations.