People exposed to more ambient solar ultraviolet radiation over their lifetimes may be at reduced risk for esophageal and esophago-gastric junction adenocarcinomas, according to recent results.
Researchers estimated the lifetime exposure to ambient solar ultraviolet radiation (UVR) of 995 Australian patients with esophageal cancer. They included 330 patients with esophageal adenocarcinoma (EAC), 386 with esophago-gastric junction adenocarcinoma (EGJAC) and 279 with esophageal squamous cell carcinoma (ESCC), as well as 1,471 controls. UVR estimates were reached according to measurements from NASA’s Total Ozone Mapping Spectrometer database for areas patients had resided in during their lives.
“There is little information from studies with individual measures about the association between sun exposure and esophageal cancer,” researcher Bich Tran, PhD, Queensland Institute of Medical Research in Brisbane, Australia, told Healio.com. “This paper is part of a body of work which aims to provide more data to enable us to generate appropriate public health recommendations.”
Risk for EAC decreased by approximately 18% (OR=0.82; 95% CI, 0.72-0.93) and risk for EGJAC decreased by 17% (OR=0.83; 95% CI, 0.73-0.94) for every 107 J/m2 increase in lifetime ambient UVR. Higher cumulative ambient UVR levels were less common among patients with EAC (OR=0.59; 95% CI, 0.35-0.99) or EGJAC (OR=0.55; 95% CI, 0.34-0.90) than in controls. All associations were independent of factors including age, sex, BMI, tobacco/alcohol consumption and reflux frequency. No association was observed between ESCC risk and high lifetime (OR=0.91; 95% CI, 0.51-1.64).
“Although excessive exposure to sunlight is a known cause of skin cancer, increasing evidence from observational studies shows that higher levels of sun exposure may reduce risk of some cancers of internal organs,” Tran said. “Findings from our study suggest that people living in regions with higher ambient UVR have lower risk of adenocarcinoma of the esophagus and esophago-gastric junction. However, it is important to note that our results do not necessarily mean that the association between UVR and EAC is causal … there may be other factors that confound the association.”
Disclosure: See the study for a full list of relevant disclosures.