Lung cancer: changes in histology, gender, and age over the last 30 years in Brazil.

Objective: To describe the trends in tumor histology, gender and age among patients with non-small cell lung cancer (NSCLC) treated with lung resection. The histology of lung cancer has changed in developed countries, and there is still little information available on the topic for developing countries.

Methods: This was a retrospective study of 1,030 patients with NSCLC treated with lung resection between 1986 and 2015 at a university hospital in southern Brazil. Differences in histology, stage, and type of surgery were analyzed by gender and for three periods (1986-1995, 1996-2005, and 2006-2015).

Results: Most (64.5%) of the patients were males, and the main histological types were squamous cell carcinoma (in 40.6%) and adenocarcinoma (in 44.5%). The mean age at surgery during the first period was 56.4 years for women and 58.9 years for men, compared with 62.2 for women and 64.6 for men in the third period (p < 0.001). The proportion of females increased from 26.6% in the first period to 44.1% in the third. From the first to the third period, the proportion of patients with squamous cell carcinoma decreased from 49.6% to 34.8% overall (p < 0.001), decreasing to an even greater degree (from 38.9% to 23.2%) among men. Among the NSCLC patients in our sample, females with adenocarcinoma accounted for 11.9% in the first period and 24.0% in the third period (p < 0.001).

Conclusions: As has been seen in developed countries, the rates of lung cancer in females in southern Brazil have been rising over the last three decades, although they have yet to surpass those observed for males in the region. The incidence of squamous cell carcinoma has decreased in males, approaching adenocarcinoma rates, whereas adenocarcinoma has significantly increased among women.