Daisuke Morinaga: Department of Respiratory Medicine, Faculty of Medicine, Hokkaido University, North 15, West 7, Kita-ku, Sapporo, 060-8638, Japan.
Jun Sakakibara-Konishi: Department of Respiratory Medicine, Faculty of Medicine, Hokkaido University, North 15, West 7, Kita-ku, Sapporo, 060-8638, Japan; Medical Network and Welfare Center, Hokkaido University Hospital, North 15, West 7, Kita-ku, Sapporo, 060-8638, Japan. Electronic address: konishj@med.hokudai.ac.jp.
Yasutaka Kawai: Department of Respiratory Medicine, Oji General Hospital, 3-4-8, Wakakusa-cho, Tomakomai, 053-0021, Japan.
Yumi Morinaga: Department of Respiratory Medicine, Obihiro-Kosei General Hospital, West 15, South 10, Obihiro, 080-0024, Japan.
Shohei Mizobuchi: Department of Respiratory Medicine, NHO Hokkaido Medical Center, 5-7-1-1, Nishi-ku, Sapporo, 063-0005, Japan.
Yoshihiro Okamoto: Department of Respiratory Medicine, NHO Hokkaido Medical Center, 5-7-1-1, Nishi-ku, Sapporo, 063-0005, Japan.
Yasunari Yamanaka: Department of Respiratory Medicine, Iwamizawa Municipal General Hospital, 9jo, West 7, Iwamizawa, 068-8555, Japan.
Kei Takahashi: Department of Respiratory Medicine, Iwamizawa Municipal General Hospital, 9jo, West 7, Iwamizawa, 068-8555, Japan.
Hajime Kikuchi: Department of Respiratory Medicine, Obihiro-Kosei General Hospital, West 15, South 10, Obihiro, 080-0024, Japan.
Noriaki Sukoh: Department of Respiratory Medicine, NHO Hokkaido Medical Center, 5-7-1-1, Nishi-ku, Sapporo, 063-0005, Japan.
Taichi Takashina: Department of Respiratory Medicine, Iwamizawa Municipal General Hospital, 9jo, West 7, Iwamizawa, 068-8555, Japan.
Hidenori Kitai: Department of Respiratory Medicine, Faculty of Medicine, Hokkaido University, North 15, West 7, Kita-ku, Sapporo, 060-8638, Japan.
Satoshi Konno: Department of Respiratory Medicine, Faculty of Medicine, Hokkaido University, North 15, West 7, Kita-ku, Sapporo, 060-8638, Japan.
BACKGROUND: Immune checkpoint inhibitors (ICIs) combined with platinum-doublet chemotherapy (ICI-chemo) have become the standard of care for extensive-stage small cell lung cancer (ES-SCLC). However, the effect of ICI-chemo on the efficacy of subsequent chemotherapy remains unknown. This study aimed to investigate the efficacy of second and subsequent treatments of SCLC with and without ICI combination therapy. METHODS: We performed an analysis of patients with ES-SCLC between January 2015 and June 2023. The ICI-chemo groups were defined as patients who received ICI-chemo as first-line therapy between September 2019 and June 2023, after ICI-chemo was reimbursed in Japan. The non-ICI-chemo groups were defined as patients who received platinum-doublet therapy between January 2015 and August 2019 and were considered eligible for ICI-chemo. RESULTS: In total, 224 patients were included (91 and 133 patients who received ICI-chemo and non-ICI-chemo, respectively). There were no significant differences in patient characteristics between the groups. There was no significant difference in progression-free survival (PFS) and overall survival (OS) for first-line treatment between the two groups. The median PFS and OS periods for second-line treatment were 3.9 and 3.9 months and 10.3 and 10.7 months in the ICI-chemo and non-ICI-chemo groups, respectively, without significant difference. Most patients in both groups received amrubicin as the second-line treatment. Moreover, the PFS and OS periods for third-line treatment were not significantly different between the ICI-chemo and non-ICI-chemo groups. CONCLUSIONS: In ES-SCLC, there is no significant additive effect on PFS and OS of second- and subsequent line treatments following ICI-chemo at first-line treatment.
