Are there differences by sex in lung cancer characteristics at diagnosis? —a nationwide study

Background Lung cancer causes approximately 25% of all cancer deaths. Despite its relevance, few studies have analyzed differences by sex at the time of diagnosis in terms of symptoms, stage, age or smoking status. We aim to assess if there are differences between men and women on these characteristics at diagnosis. Methods We analyzed the Thoracic Tumour Registry (TTR), sponsored by the Spanish Lung Cancer Group using a case-series design. This is a nationwide registry of lung cancer cases which started recruitment in 2016. For each case included, clinicians fulfilled an electronic record registering demographic data, symptoms, exposure to lung cancer risk factors, and treatment received in detail. We compared men and women using descriptive statistics. Results A total of 13,590 participants took part in this study, 25.6% women. Women were 4 years younger than men (64 vs. 69), and men had smoked more frequently. Adenocarcinoma was the most frequent histological type in both sexes. Stage IV at diagnosis was 50.8% in women compared to 43.6% in men. Weight loss/anorexia/asthenia was the most frequent symptom in both sexes and there were no differences in the number of symptoms at diagnosis. There were no relevant differences in the frequency or number of symptoms by sex when non-small cell lung cancer (NSCLC) and small-cell lung cancer (SCLC) were analyzed separately. Smoking status did not appear to cause different lung cancer presentation in men compared to women. Conclusions There seems to be no differences in lung cancer characteristics by sex at the time at diagnosis on stage, specific symptoms or number of symptoms.