Background and aims: Familial risks for esophageal cancer are not well known, especially for specific histologic types.
Methods: We used the nationwide Swedish Family-Cancer Database to examine familial risks for esophageal cancer in offspring. Standardized incidence ratios (SIRs) and 95% confidence intervals (CIs) were used to calculate the risk. Age standardized incidence rates for specific histology types of esophageal cancer were available from Swedish Cancer Registry.
Results: The incidence of male squamous cell carcinoma (SCC) reached its peak rate in 1985 and decreased afterwards. The incidence of adenocarcinoma exceeded that of SCC in 2000 among men. The SIR for offspring esophageal cancer was significantly increased when a parent presented with esophageal cancer (SIR, 2.60). The SIRs for adenocarcinoma were 4.05 and 3.52 when a parent was diagnosed with SCC and any esophageal cancer, respectively; from maternal probands the SIRs were 10.47 and 7.74, respectively. The familial SIR was above unity but not significant for SCC. For associations with other cancer sites, SCC showed a significantly increased risk when a sibling had lung cancer (SIR, 2.52).
Conclusions: The present study showed that adenocarcinoma became the major histologic type of esophageal cancer in Swedish men around 2000. For the first time we could show that familial risks of esophageal adenocarcinoma were increased when parents presented with esophageal cancer (particularly SCC). The high risk for adenocarcinoma in such families might be due to heritable effects. However, because of the limited number of familial cases, the results should be interpreted with caution.