Sex disparities in lung cancer survival rates based on screening status

Low dose computed tomography (LDCT) became the standard method for lung cancer (LC) screening in 2013. However, it is unclear whether there are differences in survival rates based on sex and whether the differences depend on screening status. We aimed to evaluate the LC survival rates between females and males based on screening.

This retrospective cohort study examined data from the Boston LC Study (BLCS) between 2013 and 2021. LC screening depends on patients' demographics (age and smoking history) to determine whether a person is a high-risk individual and, therefore, undergo LDCT. Descriptive statistics were calculated for race, age, histology, smoking history, stage, and treatment. These variables' distributions were compared between sex and screening status using t-test and chi-square, respectively. Cox proportional hazards model and Kaplan-Meier curves were used to compare survival between sex and screening. Propensity score matching was applied to account for selection bias in screening when evaluating the association between screening and stage.

A total of 1,216 LC patients were identified with a screening incidence of 9.4 %, among whom 56 % were female. Unscreened males had 1.59 times higher risk of mortality than unscreened females (P=.0002) and had a worse 5-year survival (male 50 %; 95 %CI, 0.38,0.6 vs female 70 %; 95 %CI,0.62,0.76). In contrast, there were no significant differences in survival between sexes among screened. In a balanced cohort of screened and unscreened, the odds of being diagnosed at late stages for females and smokers were 1.33 and 2.51 times that of males and nonsmokers; however, there were no statistical significance.

Unscreened females had a lower risk of mortality and better survival than unscreened males, while among the screened population, there was no difference in the overall survival. These observations demonstrate the influence of sex on survival prognosis in LC when screening is not performed.