Resistant Urothelial Carcinoma: Organ-Specific Response to Pembrolizumab
Tumor response to pembrolizumab may differ in metastases and in the primary tumor in patients with advanced urothelial cancer refractory to platinum-based chemotherapy, according to a recent Japanese retrospective study. Motonobu Nakamura, PhD, of the National Hospital Organization Kyushu Cancer Center, Fukuoka, Japan, and colleagues published their results in OncoTargets and Therapy.
“The most prominent tumor response was found in lung metastasis, and the least response was found in primary organ sites,” the investigators reported. “The mechanisms of these different responses were unclear, and there does not appear to be a constant trend between tumor shrinkage and overall survival in tumor sites.”
The retrospective study included 69 patients, 51 of them male, with a total of 226 metastases. All patients had advanced urothelial cancer and were receiving pembrolizumab after failure of platinum-based chemotherapy. A total of 32 patients had measurable lung disease, 31 had lymph node disease, 16 had a local recurrence, 14 had primary tumor organ disease, 13 had liver disease, and 7 had bone disease.
The objective response rate was 23%, and the median overall survival was 10.9 months. Organ-specific response rates were 31% for lung disease, 29% for lymph node disease, 29% for bone disease, 23% for liver disease, 13% for local recurrence, and 7% for primary tumor organ disease. Primary tumor organ disease and liver metastases were both found to be significantly associated with differences in overall survival.
The study’s main limitation is its small sample size, which was even smaller for specific organs. The two organs with significant differences in overall survival, liver and primary organ tumor, were represented by 13 and 14 patients, respectively.
Disclosure: The study authors reported no conflicts of interest.