NSCLC in never-smokers a separate disease from NSCLC in smokers

NEW YORK (Reuters Health) - Japanese investigators say that survival rates are better for non-small cell lung cancer (NSCLC) patients who were never-smokers than in NSCLC patients with a history of smoking. Other disease characteristics are different as well between the two populations.

As such, NSCLC in never-smokers should be considered a separate disease entity from NSCLC in current and past smokers, say Tokujiro Yano and colleagues at Kyushu University in Fukuoka, Japan, in the September 1 issue of Cancer.

The researchers reviewed the medical records of 1,405 patients with primary NSCLC who underwent complete resection between 1974 and 2004. Clinicopathologic variables and postoperative survival were compared for patients who never smoked and those who reported smoking currently or at some time in their past.

Dr. Yano's team found a steady increase in the proportion of never-smokers among all NSCLC patients during the 30-year study period, from 15.9% in 1974 to 32.8% by 2004. Women represented 85.8% of NSCLC never-smokers but only 11.2% of NSCLC patients with a history of smoking.

The incidence of adenocarcinomas was significantly higher among the never-smokers (87.8%) vs the smokers (49.1%).

Also, the researchers found, 40.1% of the NSCLC never-smokers had pathologic stage IA disease, compared with 25.4% of the smokers.

Overall survival and cancer-specific survival rates among the never-smoking NSCLC patients was "significantly superior" to NSCLC patients with a history of smoking.

The Kyushu University team found factors other than smoking to be significantly associated with postoperative survival on univariate analysis. The factors included gender, histologic type, T classification, and N classification.

"A multivariate analysis revealed never-smoking status to be an independent prognostic factor in addition to pathologic T and N classification," Dr. Yano and colleagues report.

There is "a need to carefully obtain the smoking history from patients because precise information regarding smoking status is a prerequisite for making an accurate diagnosis of 'never-smoking NSCLC,'" the authors advise.

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