Successful Response of Pembrolizumab Rechallenge after Radiotherapy for a Patient with Bladder Cancer of Nonresponse of Pembrolizumab First Challenge

Abstract

We report a patient with advanced bladder cancer in which the primary lesion and metastatic site disappeared following the pembrolizumab therapy rechallenge after radiotherapy for bladder cancer lesion of nonresponse of pembrolizumab first challenge. A 76-year-old man with advanced bladder cancer received three courses of the chemotherapy with gemcitabine and cisplatin combination; however, the chemotherapy was stopped because of adverse events. The patient started pembrolizumab therapy; however, the effect was not observed. Radiation therapy was given to the primary lesion and pelvic lymph node metastases for the purpose of local control of the lesions. Because the primary lesion was regrowth and para-aortic lymph node metastasis appeared, pembrolizumab therapy was resumed. Thereafter, the primary lesion and metastatic site disappeared.

Figure 1

Imaging findings. (a) CT in April 2019 at diagnosis shows the extramural invasive tumor in posterior and trigonal bladder wall. (b) CT urography at diagnosis shows the leakage of contrast media because of extravasated urine. (c) MRI at diagnosis shows that the extramural invasive tumor in posterior and trigonal bladder wall is a low signal intensity on T2-weighted image. (d) CT in December 2019 at the discontinuation of pembrolizumab therapy shows growth in the primary lesion. (e) CT in June 2020 after radiotherapy shows diminished primary tumor in size. (f) CT in September 2020 three months following radiotherapy shows regrowth of the primary lesion. (g) CT in September 2020 three months following radiotherapy shows the emergency of para-aortic lymph node metastasis (arrow: para-aortic lymph node metastasis). (h) CT in February 2021 at the end of 8 doses of pembrolizumab therapy resumption shows significant reduction of the primary lesion. (i) CT in February 2021 at the end of 8 doses of pembrolizumab therapy resumption shows almost disappearance of para-aortic lymph node metastasis.

Figure 2

Pathological findings. Pathological findings revealed invasive urothelial carcinoma (UC) (luminal type UC, papillary, G2, high grade) (H&E stain (a)), CK5/6 negative (b), CK20 weak positive (c), GATA3 strong positive (d), and PD-L1 negative (red arrow: macrophage) (e).