Dong Wook Shin MD, DrPH, MBA^{a, b}, Jong Ho Cho MD, PhD^c, Jae Myoung Noh MD, PhD^d, Hyesook Han MD, PhD^e, Kyungdo Han PhD^f, Sang Hyun Park BS^f, So Young Kim MD, MPH, PhD^{g, h}, Jong Heon Park MD, PhDⁱ, Jong Hyock Park MD, MPH, PhD^{h, i, *}, Ichiro Kawachi MD, PhD<sup>j

a</sup> Supportive Care Center, Department of Family Medicine, Samsung Medical Center, Seoul, Republic of Korea
^b Department of Digital Health, Samsung Advanced Institute of Health Sciences and Technology, Sungkyunkwan University, Seoul, Republic of Korea
^c Department of Thoracic Surgery, Samsung Medical Center, Seoul, Republic of Korea
^d Department of Radiation Oncology, Samsung Medical Center, Seoul, Republic of Korea
^e Division of Hemato-Oncology, Department of Internal Medicine, Chungbuk National University Hospital, Cheongju, Republic of Korea
^f Department of Medical Statistics, The Catholic University of Korea, Seoul, Republic of Korea
^g Department of Public Health and Preventive Medicine, Chungbuk National University Hospital, Cheongju, Republic of Korea
^h College of Medicine/Graduate School of Health Science Business Convergence, Chungbuk National University, Cheongju, Republic of Korea
ⁱ Big Data Steering Department, National Health Insurance Service, Wonju, Republic of Korea
^j T. H. Chan School of Public Health, Harvard University, Boston, Massachusetts

^*Corresponding author

Dr. Shin and Dr. Cho equally contributed to this work.

Introduction
Potential disparities in the diagnosis, treatment, and survival of patients with lung cancer with and without disabilities have rarely been investigated.

Methods
We conducted a retrospective cohort study with a data set linking the Korean National Health Service database, disability registration data, and Korean Central Cancer Registry data. A total of 13,591 people with disabilities in whom lung cancer had been diagnosed and 43,809 age- and sex-matched control subjects in whom lung cancer had been diagnosed were included.

Results
Unknown stage was more common in people with severe disabilities (13.1% versus 10.3%), especially those with a communication (14.2%) or mental/cognitive disability (15.7%). People with disabilities were less likely to undergo a surgical procedure (adjusted OR [aOR] = 0.82, 95% confidence interval [CI]: 0.77-0.86), chemotherapy (aOR = 0.80, 95% CI: 0.77-0.84), or radiotherapy (aOR = 0.92, 95% CI: 0.88-0.96). This higher likelihood was more evident for people with severe communication impairment (aORs of 0.46 for surgery and 0.64 for chemotherapy) and severe brain/mental impairment (aORs 0.39 for surgery, 0.47 for chemotherapy, and 0.49 for radiotherapy). Patients with disabilities had a slightly higher overall mortality than did people with no disability (adjusted hazard ratio = 1.08, 95% CI: 1.06-1.11), especially in the group with a severe disability (a hazard ratio = 1.20, 95% CI: 1.16-1.24).

Conclusions
Patients with lung cancer and disabilities, especially severe ones, underwent less staging work-up and treatment even though their treatment outcomes were only slightly worse than those of people without a disability. Although some degree of disparity might be attributed to reasonable clinical judgement, unequal clinical care for people with communication and brain/mental disabilities suggests unjustifiable disability-related barriers that need to be addressed.

Keywords : Lung cancer; Disability; Stage; Treatment; Survival