Does Cervical Cancer Predispose Females to Oral Cancer?

Methods: All cases of cervical, oral and oropharyngeal cancer in female residents of Queensland were extracted from the Queensland Cancer Registry for the period 1982 to 2008 and incidence of oral and oropharyngeal cancer in patients with previous cervical cancer determined. The incidence of oral and oropharyngeal cancer in the Queensland female population was calculated based on data from the registry and the Australian Bureau of Statistics. The relative risk of developing oral or oropharyngeal cancer in cervical cancer patients compared with the general female population was then determined.

Results: Over the study period 3,328 females with an epithelial cancer of the cervix were followed up for 30,375 person-years at risk of second primary oral cancer. 18 individuals (0.59/1000 person-years) were subsequently diagnosed with oral cancer, within 20 years of cervical cancer diagnosis (mean=8.1y, SD=5.6, 95% CI 5.4, 10.9). Based on census population data, the expected incidence of oral cancer among the general female population of Queensland is 0.09/1000 person-years, giving a relative risk of 6.7 (95% CI 4.1-10.9). When stratified into UV and non-UV-associated oral cancers, the relative risks were 3.7 (95% CI 1.5, 9.2) and 9.7 (95% CI 5.2, 17.4) respectively.

Conclusions: The present study shows that females with a history of cervical cancer have a greater than six times risk of subsequent oral or oropharyngeal cancer than females of the general population and that this risk increases to almost ten-fold for non-UV-associated oral cancers. Whether the proposed shared aetiological factor of HPV is the explanation for these findings deserves further investigation.