Smoking impact on survival varies with NSCLC histology
medwireNews: Japanese scientists have untangled the relationship between smoking, tumor histology and survival of patients with advanced non-small-cell lung cancer (NSCLC).
Data from 40 West Japan Oncology Group affiliated institutions between 2004 and 2005 reveal that the 1731 patients with NSCLC adenocarcinoma had significantly longer overall survival than the 740 patients with squamous, large cell, or other types of NSCLC, at 464 versus 326 days.
Analysis of the patients, all of whom had stage IIIB or IV disease, also shows that nonsmokers had significantly longer overall survival than smokers (568 vs 358 days), report Masahiko Ando, from Nagoya University Hospital, and co-workers.
Smoking significantly predicted survival in patients with adenocarcinoma, after adjusting for age, gender, stage, performance, and treatment (hazard ratio=1.34 vs nonsmokers). However, smoking had no significant impact on the survival of NSCLC patients with other types of histology.
"The prognostic difference between [adenocarcinoma] in never-smokers and smokers may suggest that both are different disease entities," the researchers say in the Journal of Thoracic Oncology.
Number of pack years smoked and time since the patient had quit smoking also significantly affected survival only for patients with adenocarcinoma.
"Although we only assessed the prognostic value of smoking status at diagnosis, assessment of smoking status at a later point, that is, at the time of treatment, would also have been of interest to determine whether cessation at the time of diagnosis leads to improved survival," Ando et al comment.
The authors also note that the prognostic impact of tumor histology and smoking status, pack-years and time since giving up smoking remained after adjusting for receipt of the epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor gefitinib. But they explain that lack of data on the EGFR status of the patients prevents determination of the impact of this agent on patient survival.
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By Lynda Williams, Senior medwireNews Reporter