Are sex and gender considered in head and neck cancer clinical studies?

We analyzed the inclusion of sex and/or gender (S/G) in Head and Neck Cancer (HNC) clinical studies, through inspecting ClinicalTrials.gov (AACT) and the mention of Human Papilloma Virus (HPV) on a specific subgroup, namely oral cavity, larynx and oropharynx. Only 5% of HNC studies mention S/G as a planned analytical variable. Proportionally more observational studies treated S/G as an analytical variable than interventional studies (10% vs 5%, P-value ≤ 0.001), 8% of studies that mentioned S/G involved more than 100 subjects while 4% less than 100 (P-value ≤ 0.001). In randomized protocols, S/G was mentioned more in studies with a planned sample of more than 100 patients and including HPV status (P-value < 0.05). Small controlled studies have lower mention of S/G as an analytical variable than uncontrolled studies (4% and 10%, respectively among studies with less than 100 subjects). Significantly greater mention of S/G as an analytical variable is observed in controlled and randomized studies with a sample size greater than 100 subjects. HPV was mentioned in only 18% of oral cavity-larynx-oropharynx studies. Interventional studies do not regularly account for S/G during HNC study design. Thus, although fundamental, in studies concerning HNC the S/G variable is often not considered. In trials published in scientific journals (P-value = 0.01) and in more recent clinical trials (P-value = 0.002), S/G is taken more into account suggesting an increasing awareness on its importance. However, the need to systematically include S/G in study design clearly emerges, to better highlight sex-related differences in disease incidence and prognosis and best imbue science and medicine with the proper biological and cultural differences.