Former smokers with non‐small‐cell lung cancers: a comprehensive investigation of clinicopathologic characteristics, oncogenic drivers, and prognosis

Abstract

The aim of this present investigation was to evaluate the clinicopathologic characteristics, oncogenic drivers, and prognosis of former smokers with non-smallcell lung cancer (NSCLC), and to compare them with those of the current and never smokers. This investigation was a single-institution retrospective study of 2289 NSCLC patients, who were classified as former, current, or never smokers. A collection was made of the clinicopathological characteristics, spectra of wellidentified driver genes and survival rates. The survival rates were compared using log-rank test, and independent prognostic factors, identified using Cox regression analysis. Of 2289 NSCLC patients, 257 (11.2%) were former smokers; 868 (37.9%), current smokers; and 1164 (50.9%), never smokers. Compared with the current, the former were characterized by older age at diagnosis (64.3y vs. 59.9y; P < 0.001), earlier TNM stage (stage I, 47.9% vs. 39.5%; P = 0.017), fewer solid predominance in adenocarcinomas (16.2% vs. 29.5%; P = 0.005), and more EGFR mutation (33.2% vs. 20.7%; P < 0.001) but less KRAS mutation (6.7% vs. 11.9%, P = 0.041). No statistically significant survival differences were observed between the former and current. However, the light former smokers presented favorable overall survival when compared with the light current and heavy former or current (the light former vs. the heavy former, P = 0.028; the light former vs. the light current, P = 0.048; and the light former vs. the heavy current, P = 0.048). Our findings suggest that the former smokers with NSCLCs can have distinctive clinicopathologic characteristics, oncogenic drivers, and prognosis, and they, especially the light former, can benefit from smoking cessation. Cancer Medicine Open Access 2118

Clinical characteristics and survival in non-small cell lung cancer patients by smoking history: a population-based cohort study

“…The present study confirms the findings from previous studies that adenocarcinoma and EGFR-mutations are overrepresented among lung cancer patients without a history of smoking [6,7,9,11,[14][15][16][17][18][19][20][21][22][24][25][26][41][42][43]. To the best of our knowledge, this was the first nationwide Nordic populationbased study finding a higher proportion of EGFR-mutations in never-smokers compared to ever smokers.…”

“…Higher survival in never-smokers, both cause-specific and overall, remained in stages I-II and IV disease. These findings of higher unadjusted survival in never-smokers confirm results from previous studies conducted in different populations and settings [10][11][12]15,17,22,26]. The lower adjusted hazards for never-smokers also confirms the findings of previous studies [11,15,17,26].…”

“…The overrepresentation of women in this group is also confirmed [7][8][9][10][11][12][14][15][16][17][18][20][21][22]24,26], and supports the notion of the presence of sex-based differences either in vulnerability to non-tobacco associated lung cancer or in exposure to other risk factors, such as environmental tobacco smoke. Due to observed sex imbalances, there has been considerable interest surrounding the possible role of oestrogen [6,9,34,35].…”

“…The observed higher proportion of both younger (<50 years) and older patients (80 years) among never-smoking has, to the best of our knowledge, never been observed before. However, there have also been reports of no differences in age and also the opposite, i.e., a younger age at diagnosis among never-smokers [7][8][9][10]14,15,[17][18][19][20][21][22]26]. None of the studies reporting an older age for never-smokers included an East Asian population.…”

“…Several studies of different size and design have compared clinical lung cancer characteristics in never-smokers with that of ever-smokers, including assessments of survival . Most of these studies were hospital-based with data from only a small number of hospitals and the majority included less than 2000 lung cancer patients [8,10,12,[15][16][17][18][20][21][22]24,26]. Despite inconsistencies between studies, the collective evidence indicates that the pathogenesis and tumour biology of lung cancer differ by smoking history.…”