Conditional survival probability for head and neck squamous cell cancer: Results from the SEER 11 Dataset

5519 Background: Survival for most cancers is typically reported as a 5-yr percentage from the time of diagnosis. Surviving patients e.g., desire to know if their likelihood for survival has improved, given that they have lived X-years since diagnosis. Conditional survival (CS) is a calculated probability of survival that demonstrates the changing likelihood of demise during a span of intervals after diagnosis. The specific aim of this study is to assess the CS for patients with head and neck squamous cell carcinoma (HNSCC). Methods: The study population included HNSCC patients from the Surveillance, Epidemiology, and End Results (SEER 11) Program. Cumulative survival rates were calculated using JMP v6 (SAS, Cary, NC) with the product-limit method, and derived on the basis of the subsequent annual survival data. Results were also sub-stratified by site of disease. Results: 90,526 patients with histologically confirmed HNSCC diagnosed from 1973 to 2001 were included. The cumulative HNSCC crude cohort 5-year CS at diagnosis is 33%, and 38% at one-year after diagnosis. 5-year CS is 43% at 2 years post-diagnosis, where it plateaus for the next 8 one-year intervals. Sub-site analysis reveals similar CS trends for all HNSCC sites except the nasopharynx. Nasopharynx cancer CS, in contrast, progressively increases over all intervals. Conclusions: HNSCCC 5-year mortality risk stabilizes within 2–3 years after diagnosis, and with the exception of nasopharyngeal cancers, does not substantially improve thereafter. The SEER data represent the largest pooled dataset for HNSCC, but do not necessarily address all relevant issues contributing to risk for death. These data, however, do provide useful estimates for HNSCC patients with known survival after diagnosis, and may have utility in the design of clinical trials which incorporate survival modeling. [Table: see text] No significant financial relationships to disclose.