Prognostic Indicators in Head and Neck Oncology Including the New 7th Edition of the AJCC Staging System

Excerpt

Head and neck squamous cell carcinoma (HNSCC) represents a number of different diseases each with unique clinical “niche” issues. Clinicopathologic or molecular studies based upon small numbers of patients which group together different anatomic sites and stages are not optimized to address these niche issues and are usually destined to have limited clinical impact. An underlying consideration for any investigation is, “Will this biomarker/indicator add prognostic value beyond known clinical confounders?” Will it retain prognostic significance after model building, which should include confounders such as site, stage, gender, age, and treatment, as well as other factors such as the continuation of smoking, race, Human Papillomavirus (HPV) status, and resection margin status? Only biomarkers/indicators that remain significantly associated with outcome after regression analysis have the potential for clinical usefulness. The number of confounders requiring consideration will impact the required cohort size to study any biomarker. It is startling how rarely this issue of sample size is mentioned in publications, and often omitted is the acknowledgment that the lack of statistical significance in small studies does not negate the possibility of a significant association. …