ALB and rheumatoid arthritis: During the study period, eight patients were excluded as follows: two patients diagnosed with secondary ILD (one with rheumatoid arthritis and one with dermatomyositis), serum Alb was not measured in one patient prior to first‐line chemotherapy administration, one patient did not receive chemotherapy, one patient was transferred from our hospital before undergoing first‐line chemotherapy, one patient had an infectious condition, and two patients received irinotecan.