PURPOSE: The incidence of lung cancer in persons below 40 years of age is low. This pattern raises questions regarding potential differences in clinical presentation, outcomes and tumor biology in these patients.
METHODS: We compared patient and disease characteristics and survival between lung cancer patients aged 15–39 years at diagnosis and those aged ≥40 years in the California Cancer Registry from 1988 to 2006. Rates were age-standardized to the 2000 US population.
RESULTS: The age-adjusted incidence rate of lung cancer in 15–39 year olds was 1.2 per 100,000, whereas that in ≥40-year olds was 141 per 100,000. 2728 patients aged 15–39 years, comprising 0.08% of all lung cancer patients, were identified. 48% were female (vs. 45% female among those aged ≥40 years, p<0.01). 55% of patients were white, 19% Hispanic, 12% black and 12% Asian; this racial distribution differed significantly from that in ≥40-year-olds (78% white, 8% Hispanic, 7% black and 6% Asian; p<0.01). A higher proportion of younger patients (57%) had distant disease at diagnosis compared with older patients (51%, p<0.01). The distribution of histologic subtypes also differed significantly between younger patients (39% adenocarcinoma, 9% squamous-cell carcinoma, 7% small-cell carcinoma, 6% large-cell carcinoma, 3% bronchioloalveolar carcinoma, and 35% other) and older patients (specifically 30% adenocarcinoma, 19% squamous-cell carcinoma, 13% small-cell carcinoma and 28% other; p<0.01). Mean five-year cause-specific survival was 34% in the 15–39 year age group and 16% in the ≥40-year age group (p<0.01). At each disease stage, mean one and five-year cause-specific survival rates were better in the younger group.
CONCLUSION: These findings suggest that lung cancer in the very young exhibits distinct clinical features, including higher proportion with distant disease at presentation, different racial distribution, differing proportions of histologic subtypes, and better survival at each stage.
CLINICAL IMPLICATIONS: Our results provide information on clinical epidemiology, including survival data, of lung cancer in the very young. These results may inform discussions with patients and prompt research into lung cancer in the very young as a distinct clinical entity.
DISCLOSURE: Laveena Chhatwani, No Financial Disclosure Information; No Product/Research Disclosure Information