Familial risk in head and neck squamous cell carcinoma diagnosed before the age of 45: a population-based study

This population-based study analyses familial risk as a factor in the devel opment of head and neck squamous cell carcinoma before the age of 45. Two d ifferent designs. were used: (1) estimation of standardised incidence ratio s (SIRs) for cancer among first-degree relatives of 127 young head and neck cancer probands; and (2) estimation of odds ratios (ORs) for developing he ad and neck cancer associated with cancer in a first-degree relative. SIRs of cancer of the respiratory and upper digestive tract (lungs, oesophagus, and smoking-related head and neck sites [RUDT]) for first-degree relatives were 4.3 (95% confidence intervals or 95%CI of 1.6-9.5) for female patients , 1.0 (95%CI = 0.3-2.6) for male patients and 1.9 (95%CI = 0.9-3.5) for bot h sexes combined. ORs for bead and neck cancer before the age of 45, in ass ociation with cancer of RUDT in a first-degree relative were 5.0 (95%CI= 1. 4-17.3) for women, 1.1 (95%CI = 0.3-3.3) for men, and 2.0 (95%CI = 0.9-4.4) for both sexes combined. Hence, when analysing both sexes combined, our fa milial risk estimates for head and neck cancer showed non-significant incre ases. An explanation for the unexpected sex asymmetry in familial risk coul d be an interaction between inherent cancer susceptibility and a female bio logical characteristic. Alternatively, it could be artefacts caused by diff erences in familial smoking habits. (C) 1999 Published by Elsevier Science Ltd. All rights reserved.