What happened, in summary

A 78-year-old man with type 2 diabetes was diagnosed in August 2017 with Stage IV gastric cancer and a portal-vein tumor thrombus. First-line S-1 plus oxaliplatin and second-line ramucirumab plus paclitaxel were both stopped because the cancer progressed. Nivolumab immunotherapy was started as third-line treatment in September 2018.

Nivolumab initially controlled the primary stomach tumor and brought an elevated CEA tumor marker back into the normal range. Within 2 months, however, urine testing began showing increasing protein and blood. Nivolumab was later stopped when he developed bacterial pneumonia and his overall condition worsened.

Over the following months, kidney abnormalities progressed. A renal biopsy showed IgA nephropathy, considered related to nivolumab. While immunotherapy was being withheld, the gastric tumor began growing again. Restarting nivolumab was considered, but progressive kidney injury initially made that difficult.

Prednisolone was started in June 2019 and gradually tapered. His kidney function stabilized and the heavy protein loss in the urine improved substantially. Even after the renal problem improved, recurrent bacterial pneumonia left him too unwell to restart nivolumab. At the latest follow-up, the Stage IV gastric cancer had regrown during the treatment interruption.