Survival probabilities and trends for lip, oral cavity and oropharynx cancers in Northern Portugal in the period 2000-2009.

Background: Oral cancer represents a serious public health problem worldwide. Our aim was to analyse the survival probabilities and trends of patients presenting with lip, oral cavity and oropharynx cancers, who were residents in the north of Portugal.

Methods: Using cancer-registry data, we conducted a population-based study of lip, oral cavity and oropharynx cancers diagnosed in the period 2000-2009, among residents in the north of Portugal. Net survival was estimated using the Pohar-Perme estimator. Excess hazard ratios (for gender, age group, tumour location, stage, residence area and period of diagnosis) were estimated using flexible parametric models.

Results: A total of 2,947 cases (79.5% males) were included of which 18.5% were located on the lip, 56.2% in the oral cavity and 25.3% in the oropharynx. A large proportion of patients were diagnosed in stages III and IV (18.6% and 48.7%, respectively). The 5-year net survival (5yr-NS) for all three cancer sites together was 46% (95%CI 44-48), being 88% (95%CI 83-94), 41% (95%CI 38-43) and 27% (95%CI 23-30) for lip, oral cavity and oropharynx cancer, respectively. The 5yr-NS stratified by tumour stage was 84% (95%CI 78-90) for stage I, 69% (95%CI 63-76) for stage II, 42% (95%CI 37-47) for stage III and 19% (95%CI 16-21) for stage IV. When comparing the periods 2000-4 and 2005-9, no overall improvements in survival were observed. However, when analysed by stage, a significant reduction in the adjusted excess mortality was observed for stages II ( p = 0.021) and III ( p < 0.001).

Conclusion: More than half of the oral cavity and oropharynx cancers were diagnosed in advanced stages of the disease, having a low survival probability. Improvements in survival in the first decade of this century were limited to stages II and III, which were the result of changes in hospital cancer care practices.