Is there a gender difference in non-small cell lung cancer survival?
BACKGROUND
A possible association had previously been noted between gender and prognosis in non-small cell lung cancer (NSCLC), with a better survival rate for women.


OBJECTIVE
The purpose of the current study was to further clarify the role of gender as a possible prognostic factor in NSCLC.


METHODS
This retrospective cohort study examined the survival of NSCLC patients who underwent surgical curative treatment at the Hospital Sao Lucas da PUCRS, Porto Alegre, Brazil, between January 1, 1990, and December 31, 2000. Data were analyzed using Kaplan-Meier survival curves. In addition, a Cox proportional hazards regression model was used to adjust for potential confounding factors.


RESULTS
In the period studied, lung resections were performed in 253 patients with NSCLC, of whom 114 had stage I tumors. Four patients were excluded because of death in the immediate postoperative period, and 1 committed suicide. The 5-year survival rate was 85.5% for women and 46.4% for men (P<0.0001). The median overall survival time was 44.7 months (interquartile range [IQR(25%-75%)], 17.4-72.3 months) and was longer in women than in men: 63.9 months (IQR(25%5%), 35.2-98.7 months) versus 32.3 months (IQR(25%-75%), 11.8-61.5 months), respectively (P<0.0001). Gender effect was still present after adjustment by Cox regression for several factors (age, smoking habits, hemoglobin, forced expiratory volume in 1 second, tumor size, tumor-node-metastasis stage, histology, postoperative complications, and surgery type). The adjusted hazard ratio in women was 0.23 (95% CI, 0.09-0.59; (P<0.0001) when compared with men.


CONCLUSIONS
This study confirms previous findings that women live longer than men after surgery for stage I NSCLC. This effect persisted after adjusting for several factors. These results highlight the fact that analyses of long-term survival of NSCLC patients, usually generalized to men and women as a whole, may be an inadequate extrapolation. These results question whether analyses of long-term survival, which commonly group men and women together, provide an adequate prognosis of survival rates in women with NSCLC.
Chatkin
José M
JM
Pontifícia Universidade Catolíca of Rio Grande do Sul (PUCRS), Catholic School of Medicine, Porto Alegre, Brazil. jmchatkin@pucrs.br
Abreu
Carolina M
CM
Fritscher
Carlos C
CC
Wagner
Mário B
MB
Pinto
Jose A L F
JA
D001938:Brazil / Q000453:epidemiology; D002289:Carcinoma, Non-Small-Cell Lung / Q000401:mortality* / Q000473:pathology / Q000601:surgery; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000401:mortality* / Q000473:pathology / Q000601:surgery; D008297:Male; D011379:Prognosis; D016016:Proportional Hazards Models; D012189:Retrospective Studies; D017678:Sex Distribution; D012737:Sex Factors; D015996:Survival Rate