Introduction: A shift in etiology of oral cancers has been associated with a rise in incidence for oropharyngeal cancers (OPC) and decrease for oral cavity cancers (OCC); however, there is limited information about population-based survival trends. We report epidemiological transitions in survival for both OPC and OCC from a population-based cancer registry, focusing upon gender and ethnic differences.
Methods: All primary oral cancers diagnosed between 1980 and 2005 were identified from the British Columbia Cancer Registry and regrouped into OPC and OCC by topographical subsites, time periods (1980-1993 and 1994-2005), stage at diagnosis, and ethnicity. Cases were then followed up to December 2009. Using gender-based analysis, actuarial life tables were used to calculate survival rates, which were compared using Kaplan-Meier curves and log-rank tests.
Results: For OPC, survival improved, significant for tonsil and base of tongue in men and marginally significant at base of tongue in women. This improvement occurred in spite of an increase in late-stage diagnosis for OPC in both genders. Interestingly, there was no difference in survival for early- and late-stage disease for OPC in men. For OCC, there was a decrease in survival for floor of mouth cancers in both genders although significant in women only. South Asians had the poorest survival for OCC in both genders.
Conclusion: Survival for OPC improved, more dramatically in men than women, in spite of late-stage diagnosis and increasing nodal involvement. Given the poor survival rates and need for early detection, targeted OCC screening programs are required for South Asians.