Clinical Features of Lung Cancer in Japanese Patients Aged Under 50

The proportion of lung cancer patients under 50 years old is small at approximately 510%, but as with patients older than 50, the number is on the rise. Although lung cancer treatment strategies have undergone extensive transformation in recent years based on the presence or absence of oncogenic driver mutations, there are few reports regarding these mutations in the young or the relationship between clinical setting and prognosis. Therefore, we conducted a study of clinical features in 36 patients under the age of 50 who were diagnosed with primary lung cancer from October 2008 to November 2015. The 22 patients in stages I through III A underwent operations, and all 17 whose lung cancer were detected through screening were candidates for surgery. Gene analysis was conducted for 26 (72.2%); 10 (38.5%) were positive for EGFR gene mutations, and ALK gene translocation was present in 4 (15.4%). In stage IV patients, the median progression free survival (PFS) in the ALK translocation positive and negative patients was 518 days and 130 days, respectively, and the median overall survival (OS) was not reached and 280 days, respectively. A trend toward extended PFS (p=0.203) and OS (p=0.056) was observed in patients positive for ALK translocation. We must strive for early detection by increasing screening rates and evaluate oncogenic driver mutations important for prognosis of lung cancer in the young.