Lung cancer in young patients: tumour characteristics and treatment in an Irish population.

Background: Lung cancer is the leading cause of cancer death in both sexes in Ireland. Studies suggest that lung cancer in younger patients has distinct characteristics. The aim of this study is to define the characteristics of lung cancer in patients 55-year-old or younger in an Irish population.

Methods: Data was collected retrospectively from local medical records and the hospital electronic database regarding all patients diagnosed with lung cancer aged 55-year-old and younger, from 2010-2016. Information regarding patient demographics, smoking status, tumour histology, molecular analysis, stage and location, diagnostic modality and initial treatment choice was collected. In all cases the diagnosis of lung cancer was confirmed at the regional lung cancer multidisciplinary team (MDT) meeting.

Results: In total, 8% (n=130) of all cases of lung cancer diagnosed from 2010 to 2016 in our center occurred in patients aged 55 years old or younger; 83% (n=108) were 45 to 55-year-old, 15% (n=19) were 35 to 44-year-old and 2% (n=3) were younger than 35-year-old; 88% (n=115) of patients reported a smoking history. There was a female preponderance (58%, n=76), higher rates of NSCLC non-squamous subtype (53%, n=69) and an upper lobe predominance (42%, n=54); 53% (n=68) of patients had IV or extensive disease at presentation. Epidermal growth factor receptor (EGFR), anaplastic lymphoma kinase (ALK) and Kirsten rat sarcoma oncogene (KRAS) mutation rates were 9% (n=4) and 3% (n=1) and 80% (n=4) respectively.

Conclusions: Lung cancer in younger patients has distinct characteristics. This study suggests a female preponderance, high smoking rates and a predilection for the upper lobes. Further large-scale multicenter studies are required to verify these results and to clarify the responsible mechanisms.