Objective: To study whether the clinico-pathologic characteristics and survival of young lung cancer patients < 40 years of age differ from those of lung cancer patients >or= 40 years of age.
Methods: Retrospective analysis was carried out to compare the clinico-pathologic features and survival of 129 young patients (young group) with those of 140 randomly selected older ones (elderly group).
Results: The young group, when compared with the older group, had more female (P = 0.037), longer mean duration of symptoms (4.7 m vs 2.5 m, P < 0.001), higher misdiagnostic rate (65.1% vs 24.3%, P < 0.001) with longer mean duration of misdiagnosis for the misdiagnosed patients (5.6 m vs 2.5 m, P < 0.001), more adenocarcinoma (54.3% vs 42.1%, P < 0.001), higher pathologic grade (69.5% vs 36.0%, P < 0.001), more advanced-stage diseases at diagnosis (74.4% vs 45.7%, P < 0.001), more patients receiving combined-modality treatment (94.6% vs 62.1%, P < 0.001) and more distant failures as initial relapse (64.7% vs 50.6%, P = 0.02). The median survivals and 5-year survival rates were better in patients with stage I-II disease in the young group than the older group (54 m vs 33 m and 46.2% vs 25.0%, P = 0.0495), even though the overall median survivals and 5-year survival rates were similar in either group (11 m vs 14 m and 8.3% vs 11.9%, P = 0.2889). There was no difference in family or smoking history (P = 0.227 and 0.171).
Conclusion: Younger patients with lung cancer present difference in clinico-pathologic features from the older ones, but the survivals of the two groups are similar. To define younger lung cancer as "the younger type of lung cancer" may have a practical clinical significance.