[Survival in Lung Cancer among Female Never-smokers in Rural Xuanwei and Fuyuan Counties in Eastern Yunnan Province, China].

BACKGROUND: Lung cancer rates among women in rural Xuanwei and Fuyuan counties in eastern Yunnan province, China, are among the highest in the world, even though almost all women are non-smokers, and they tend to develop lung cancer at a younger age than other locations by roughly 5 yr-10 yr. This study investigated the survival of lung cancer patients among female never-smokers. METHODS: The female never-smokers, who had lived for many years in Xuanwei and Fuyuan counties, with lung cancer newly-diagnosed between July 2006 to March 2010, were followed up through the end of 2016. Age-standardized relative survival for all cases was calculated using local life table. The Kaplan-Meier method and Log-rank test were used to analyze the relationship between the variables and the prognosis in univariate analysis. Cox regression analysis was employed in the multivariate analysis. RESULTS: Among 1,250 total subjects, 1,075 died and the remaining 175 were censored during the follow-up, with a median follow-up period of 69 months (95%CI: 61.9-76.0). Overall, the mean age was (54.8 ±10.9) yr, with variable clinical stages: 3.5% of cases were stage I, 8.7% stage II, 20.7% stage III, 29.7% stage IV, and 37.4% stage unknown. The 645 patients(51.6%) with cyto-histological diagnosis contains 303 with Squamous cell carcinoma, and 231 with adenocarcinoma, 24 with small cell, 43 with other specified type and 39 with unknown histological type. Only 215 (17.2%) patients received surgery, 487 (39.0%) were treated without surgery, and 548 (43.8%) did not receive any specific anticancer therapy. The 5-year observed survival rate and age-standardized relative survival were 8.9% (95%CI: 7.0-10.6), and 10.1% (95%CI: 3.7-20.5) respectively, with a median survival of 13.2 months. The 5-year survival rates were 41.1% for stage I, 22.4% for stage II, 5.3% for stage III, 1.3% for stage IV, 11.2% for missing stage, 17.9% for adenocarcinoma, and 5.6% for squamous cell carcinoma respectively. Surgery significantly improved 5-year survival rate compared with non-surgery (34.8% vs 3.2%, P<0.001). The patients with non-treatment, aged 65 years and older, living in rural areas and farmer with low socioeconomic status had poorer survival, whereas the patients treated in provincial hospitals and chest X-ray screening had better survival. Cox multivariate analysis further showed that stage of tumor-node-metastasis (TNM), treatment status, hospital-level, and X-ray screening were factors correlated with survival. CONCLUSIONS: Patients with lung cancer among female never-smokers in Xuanwei and Fuyuan experience poorer survival, because they are less likely to be diagnosed at early stage, as well as less likely to receive surgery and comprehensive treatment. Furthermore low socioeconomic status and poor health security are also responsible for the low survival.