EGFR, Kras mutations are frequently positive in adenocarcinoma among all lung cancers. HER2, BRAF mutations or EML4-ALK, RET, ROS1 translocations are identified in lesser numbers. Although adenocarcinomas emerging in younger patients are presumably associated with some driver oncogenes including these mutations/translocations, details remain unknown.
We retrospectively screened 67 consecutive patients who were diagnosed as stage I-IV adenocarcinoma at the age of 40 years or less in 2009-2014. We analyzed clinical and genetic characteristics among them.
Out of 67 patients, 27 (40%) were male, 26 (39%) were never-smoker, and 45 (68%) were stage IV, with the median age of 36 years (range; 26-40). Fifty-five patients (82%) were identified with some driver oncogene. Thirty (45%) had EML4-ALK translocation, 19 (28%) had EGFR mutation, and 2 (3%) had Kras mutation. Most of the EGFR-mutant patients had exon 19 deletion (14/19; 74%). Furthermore, we examined rare oncogenes in 12 out of 15 triple-negative patients, which revealed three patients had HER2 mutation and two had RET translocation. Twenty-six stage IIIB-IV patients with EML4-ALK translocation received ALK-inhibitors; the median progression-free survival was 8.9 months (95% CI: 4.8-10.8 months).
82% of early-emerging adenocarcinoma was identified with some targetable driver oncogenes. Among younger populations, examination of all known driver oncogenes is recommended.
Clinical trial identification
All authors have declared no conflicts of interest.