Background: Xuanwei and Fuyuan are rural counties, located in the late Permian coal poly area of eastern Yunnan and western Guizhou, where lung cancer mortality rates are among the highest in the China, with similarity for both men and women, younger age at diagnosis and death, and higher in rural areas than in urban areas. In this paper, long-term follow-up of lung cancer cases in local peasants was conducted to observe their survival prognosis and its influencing factors.
Methods: Data of patients diagnosed with lung cancer from January 2005 to June 2011, who had lived in Xuanwei and Fuyuan counties for many years, were collected from 20 hospitals at the local provincial, municipal and county levels. To estimate survival outcomes, individuals were followed up until the end of 2021. The 5-year, 10-year and 15-year survival rates were estimated using the Kaplan-Meier method. Survival differences were examined with Kaplan-Meier curves and Cox proportional hazards models.
Results: A total of 3,017 cases were effectively followed up (2,537 peasants and 480 non-peasants). The median age at diagnosis was 57 years, and the median follow-up time was 122 months. During the follow-up period, 2,493 cases (82.6%) died. The distribution of cases by clinical stage was as follows: stage I (3.7%), stage II (6.7%), stage III (15.8%), stage IV (21.1%) and unknown stage (52.7%). Treatment at the provincial, municipal and county-level hospitals accounted for 32.5%, 22.2% and 45.3%, respectively, and surgical treatment was performed in 23.3% of cases. The median survival time was 15.4 months (95%CI: 13.9-16.1), and the 5-year, 10-year and 15-year overall survival rates were 19.5% (95%CI: 18.0%-21.1%), 7.7% (95%CI: 6.5%-8.8%) and 2.0% (95%CI: 0.8%-3.9%), respectively. Peasants with lung cancer had a lower median age at diagnosis, higher proportion residing in remote rural areas, and higher use of bituminous coal as a household fuel. They also have a lower proportion of early-stage cases, treatment at provincial or municipal hospitals, and surgical treatment, leading to poorer survival outcomes (HR=1.57). Even when considering factors such as gender, age, residential location, clinical stage at diagnosis, histological type, hospital level of service, and surgical intervention, peasants still exhibit a survival disadvantage. Multivariable Cox model analysis comparing peasants and non-peasants reveals that surgical intervention, tumor-node-metastasis (TNM) stage, and hospital level of service are common factors influencing survival prognosis, while the use of bituminous coal as a household fuel, hospital level of service and adenocarcinoma (compared to squamous cell carcinoma) are independent prognostic factors for lung cancer survival among peasants.
Conclusions: The lower lung cancer survival rate among peasants is associated with their lower socioeconomic status, lower proportion of early-stage diagnoses, lower proportion of surgical interventions, and treatment at provincial-level hospitals. Furthermore, the impact of other factors such as high-risk exposure to bituminous coal pollution on survival prognosis requires further investigation.
【中文题目：滇东产煤区农民住院肺癌病例长期生存分析】 【中文摘要：背景与目的 宣威市、富源县是位于滇东黔西晚二叠纪聚煤区的农村县，其肺癌死亡率却是中国最高的地区，而且男女差别小，死亡年龄提前，农村居民高于城镇居民。本文对当地农民肺癌病例进行长期随访，观察其生存预后及其影响因素。方法 对2005年1月-2011年6月入住当地省、市、县级20家医院的宣威市、富源县籍肺癌患者随访至2021年末，应用Kaplan-Meier法计算5年、10年和15年生存率，并进行单因素和Cox比例风险模型多因素生存分析。结果 有效随访3,017例（农民2,537例，非农民480例），中位诊断年龄57岁，中位随访时间122个月，随访期间死亡2,493例（82.6%）。I期、II期、III期、IV期和未知分期分别占3.7%、6.7%、15.8%、21.1%和52.7%，手术治疗占23.3%，省、市和县级医院治疗分别占32.5%、22.2%和45.3%。中位生存期为15.4个月，5年、10年和15年总生存率分别为19.5%（95%CI: 18.0%-21.1%）、7.7%（95%CI: 6.5%-8.8%）和2.0%（95%CI: 0.8%-3.9%）。农民肺癌诊断年龄偏低，居住偏僻乡村、以烟煤为生活燃料的比例较高，而早期病例、省市级医院和手术治疗比例较低，生存预后也较差（HR=1.57），且即使在同一性别、年龄、居住位置、临床分期、组织类型、治疗医院级别和手术与否等方面均表现出生存劣势。农民与非农民的Cox模型分析显示，手术与否、肿瘤原发灶-淋巴结-转移（tumor-node-metastasis, TNM）分期是二者肺癌患者生存的的共同预后影响因素，而是否以烟煤为生活燃料、诊治医院级别、腺癌（相比于鳞癌）仅是农民肺癌生存的独立预后因素。结论 农民较低的肺癌生存率与其社会经济水平较低及诊断时早期病例、手术、省级医院治疗等比例较低有关，其次煤烟污染的高风险暴露等其他因素对生存预后的影响尚待进一步研究。】 【中文关键词：肺肿瘤；生存；预后因素；农民；宣威；富源】.
Keywords: Fuyuan; Lung neoplasms; Peasants; Prognostic factors; Survival; Xuanwei.