title: Report of two cases of pseudoprogression in patients with non-small cell lung cancer treated with nivolumab-including histological analysis of one case after tumor regression.
abstract: The recent approval of nivolumab and other immune-checkpoint inhibitors for the treatment of certain solid tumors including non-small cell lung cancer (NSCLC) has transformed cancer therapy. However, it will be important to characterize effects of such agents not seen with classical cytotoxic drugs or other targeted therapeutics. We here report two cases of NSCLC showing so-called pseudoprogression during nivolumab treatment. In both cases, imaging assessment revealed that liver metastatic lesions initially progressed but subsequently shrank during continuous nivolumab administration, with treatment also resulting in a decline in serum levels of carcinoembryonic antigen. Histological evaluation of the liver metastatic lesion of one case after regression revealed fibrotic tissue containing infiltrated lymphocytes positive for CD3, CD4, or CD8 but no viable tumor cells, suggestive of a durable immune reaction even after a pathological complete response. Given the increasing use of immune-checkpoint inhibitors in patients with NSCLC or other solid tumors, further clinical evaluation and pathological assessment are warranted to provide a better understanding of such pseudoprogression.
authors.affiliation: Department of Medical Oncology, Kindai University Faculty of Medicine, 377-2 Ohno-higashi, Osaka-Sayama, Osaka 589-8511, Japan.
authors.forename: Junko
authors.initials: J
authors.lastname: Tanizaki
authors.affiliation: Department of Medical Oncology, Kindai University Faculty of Medicine, 377-2 Ohno-higashi, Osaka-Sayama, Osaka 589-8511, Japan. Electronic address: hayashi_h@dotd.med.kindai.ac.jp.
authors.forename: Hidetoshi
authors.initials: H
authors.lastname: Hayashi
authors.affiliation: Department of Pathology, Kindai University Faculty of Medicine, 377-2 Ohno-higashi, Osaka-Sayama, Osaka 589-8511, Japan.
authors.forename: Masatomo
authors.initials: M
authors.lastname: Kimura
authors.affiliation: Department of Medical Oncology, Kindai University Faculty of Medicine, 377-2 Ohno-higashi, Osaka-Sayama, Osaka 589-8511, Japan.
authors.forename: Kaoru
authors.initials: K
authors.lastname: Tanaka
authors.affiliation: Department of Medical Oncology, Kindai University Faculty of Medicine, 377-2 Ohno-higashi, Osaka-Sayama, Osaka 589-8511, Japan.
authors.forename: Masayuki
authors.initials: M
authors.lastname: Takeda
authors.affiliation: Department of Pathology, Kindai University Faculty of Medicine, 377-2 Ohno-higashi, Osaka-Sayama, Osaka 589-8511, Japan.
authors.forename: Shigeki
authors.initials: S
authors.lastname: Shimizu
authors.affiliation: Department of Pathology, Kindai University Faculty of Medicine, 377-2 Ohno-higashi, Osaka-Sayama, Osaka 589-8511, Japan.
authors.forename: Akihiko
authors.initials: A
authors.lastname: Ito
authors.affiliation: Department of Medical Oncology, Kindai University Faculty of Medicine, 377-2 Ohno-higashi, Osaka-Sayama, Osaka 589-8511, Japan.
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Nakagawa
mesh_terms: D000230:Adenocarcinoma / Q000000981:diagnostic imaging / Q000188:drug therapy* / Q000473:pathology*; D000077192:Adenocarcinoma of Lung; D000368:Aged; D000911:Antibodies, Monoclonal / Q000627:therapeutic use*; D000970:Antineoplastic Agents / Q000627:therapeutic use; D018450:Disease Progression; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000000981:diagnostic imaging / Q000188:drug therapy* / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D000077594:Nivolumab; D015898:Tomography Scanners, X-Ray Computed
chemical_list: D000911:Antibodies, Monoclonal; D000970:Antineoplastic Agents; D000077594:Nivolumab
keywords: Adenocarcinoma; Nivolumab; Non–small cell lung cancer; Pseudoprogression