Protective effect of height on long-term survival of resectable lung cancer: a new feature of the lung cancer paradox.

Introduction: Unlike most malignancies, higher body mass index (BMI) is associated with a reduced risk of lung cancer and improved prognosis after surgery. However, it remains controversial whether height, one of determinants of BMI, is associated with survival independently of BMI and other confounders.

Methods: We extracted data on all consecutive patients with resectable non-small cell lung cancer included in Epithor, the French Society of Thoracic and Cardiovascular Surgery database, over a 16-year period. Height was analysed as a continuous variable, and then categorised into four or three categories, according to sex-specific quantiles. Cox proportional hazards regression was used to estimate the association of height with survival, adjusted for age, tobacco consumption, forced expiratory volume in one second (FEV), WHO performance status (WHO PS), American Society of Anesthesiologists (ASA) score, extent of resection, histological type, stage of disease and centre as a random effect, as well as BMI in a further analysis.

Results: The study included 61 379 patients. Higher height was significantly associated with better long-term survival after adjustment for other variables (adjusted HR 0.97 per 10 cm higher height, 95% CI 0.95 to 0.99); additional adjustment for BMI resulted in an identical HR. The prognostic impact of height was further confirmed by stratifying by age, ASA class, WHO PS and histological type. When stratifying by BMI class, there was no evidence of a differential association (p=0.93). When stratifying by stage of disease, the prognostic significance of height was maintained for all stages except IIIB-IV.

Conclusions: Our study shows that height is an independent prognostic factor of resectable lung cancer.