Adherence to guideline-recommended low-dose CT lung cancer screening among breast cancer survivors with a history of tobacco use.

Abstract

668 Background: Adherence to lung cancer screening remains suboptimal. Breast cancer survivors are at increased risk for second primary malignancies, including lung cancer, underscoring the need for guideline-concordant screening during survivorship. Breast cancer survivors meeting U.S. Preventive Services Task Force (USPSTF) lung cancer screening criteria represent a high-risk subgroup that may benefit from early detection, yet there is a paucity of literature examining lung cancer screening in this population. This study evaluated screening adherence and identified factors associated with screening completion among breast cancer survivors with a history of tobacco use. Methods: Women aged 50–80 with diagnoses of breast cancer and tobacco use between 2019 and 2024 were identified by ICD-10 codes within a single institution. Smoking history was ascertained through chart review. Of 297 patients reviewed, 118 met USPSTF criteria for lung cancer screening (≥20 pack-years, current smoker or quit within 15 years). Screening adherence was defined as completion of at least one low-dose CT scan (LDCT) after breast cancer diagnosis. Demographic, clinical, and healthcare access variables were analyzed using univariate analyses and multivariable logistic regression. Statistical significance was set at p<0.05. Results: Among 118 eligible patients, lung cancer screening adherence was 68%. Notably, 87% of missed screenings resulted from failures in ordering or completing LDCT rather than patient refusal. On univariate analysis, factors associated with higher adherence included White race (p=0.031), primary care (PCP) visit within 12 months of breast cancer diagnosis (p<0.001), having a pulmonologist (p<0.001), COPD (p<0.001), and early-stage breast cancer (p=0.009). Factors associated with lower adherence included former smoking status (p=0.017), mastectomy (p=0.013), and chemotherapy receipt (p=0.009). On multivariable analysis, independent predictors of screening completion included PCP visit within 12 months of breast cancer diagnosis (OR 6.74, p=0.001), having a pulmonologist (OR 5.88, p=0.004), and history of COPD (OR 3.51, p=0.026). Former smoking (OR 0.19, p=0.009) and mastectomy (OR 0.18, p=0.004) were associated with lower odds of screening. Screening completion was not associated with distance to hospital, area deprivation index, or insurance type. Conclusions: Most missed screenings resulted from system-level barriers in ordering or completing screening rather than patient refusal. PCP engagement was the strongest predictor of screening completion. Improving oncology-PCP coordination, integrating screening reminders into survivorship care plans, and targeting outreach to non-white patients and former smokers may enhance screening adherence in this high-risk population.