Smoking at diagnosis is an independent prognostic factor for cancer-specific survival in head and neck cancer: findings from a large, population-based, study
Menée en Irlande à partir des données du registre national des cancers portant sur 5 652 patients atteints d'un cancer de la tête et du cou, cette étude en population évalue l'association entre le tabagisme au moment du diagnostic et la survie des patients, en fonction de la localisation du cancer (cavité orale, pharynx, larynx) et des traitements reçus
Background: Some studies suggest smoking may result in poorer clinical outcomes in head and neck cancer, but the evidence is heterogeneous and some of it is poor quality. In a large, population-based, study we investigated: (1) whether smoking at diagnosis is an independent prognostic factor for cancer-specific survival in head and neck cancer; and (2) whether the association varies by site and treatment. Methods: Head and neck cancers (ICD10 C01-C14, C30-32) diagnosed 1994-2009 were abstracted from the National Cancer Registry Ireland, and classified by smoking status at diagnosis. Follow-up was for 5 years or until December 31, 2010. Multivariate Cox proportional hazards models were used to compare cancer-specific death rates in current, ex- and never smokers. Subgroup analyses by site and treatment were conducted. Results: 5,652 head and neck cancers were included. At diagnosis, 24% were never smokers, 20% ex-smokers and 56% current smokers. Compared to never smokers, current smokers had a significantly raised death rate from cancer (multivariate HR=1.36, 95%CI 1.21-1.53). The association was similar after restriction to squamous cell tumours. A significantly increased cancer death rate was seen for current smokers with oral cavity, pharyngeal and laryngeal cancers. The association was stronger in surgically-treated patients (HR=1.49, 95%CI 1.25-1.79; p(interaction)=0.01). Neither radiotherapy nor chemotherapy modified the effect of smoking. Conclusions: Head and neck cancer patients who smoke at diagnosis have a significantly increased cancer death rate . Impact: Greater efforts are needed to encourage and support smoking cessation in those at risk of, and diagnosed with, head and neck cancer.