Clinicopathologic characteristics and EGFR mutations in lung cancer patients aged below 45 years.

Patients aged ≤45 years are rarely diagnosed as lung cancer. Therefore, this paper describes a retrospective study which was conducted to understand the clinicopathologic characteristics and epidermal growth factor receptor (EGFR) mutations in these young lung cancer patients. All patients diagnosed as lung cancer from January 2014 to December 2016 at Huai'an First People's Hospital were enrolled in this study. Their clinicopathologic manifestations and EGFR mutations were recorded, and the difference between those aged less than 45 years and those aged above 45 years was compared. A total of 1472 patients were enrolled in this study, including 73 (4.95%) younger patients (≤45 years old) and 1399 older patients (>45 years old). The proportions of female patients (57.5% vs 32.2%, P = 0.000), nonsmokers (79.5% vs 54.2%, P = 0.000), and adenocarcinoma (72.6% vs 54.8%, P = 0.000) were higher in the younger group, while the primary location of lung cancer and the selection of surgical treatment showed no significant difference between the 2 groups. Among all 1472 patients, there were 1410 cases of nonsmall cell lung carcinoma (NSCLC), whose stage distribution was significantly different between the 2 groups (stage I/II and carcinoma in situ: 38.0% vs 40.1%; stage III/IV: 62.0% vs 52.4%, P = 0.047). There was no significant difference in the number of T stage and N stage cases between the 2 groups. The EGFR mutation rate and overall survival were not significantly different between the 2 groups. In conclusion, lung cancer in young patients (≤45 years old) was associated with unique characteristics, with greater percentages of female patients, adenocarcinoma, nonsmokers, and advanced tumor stage.