Nivolumab exerts therapeutic effects against metastatic lesions from early gastric adenocarcinoma with a small proportion of neuroendocrine carcinoma after gastrectomy: a case report

Multimodal Treatment With Nivolumab Contributes to Long-Term Survival in a Case of Unresectable Esophagogastric Junction Neuroendocrine Carcinoma

Advanced neuroendocrine carcinoma (NEC) has an extremely poor prognosis, partly explained by the rarity and diagnostic difficulty, for which the most appropriate treatment strategy has not been established. In this report, we discuss a case of unresectable advanced esophagogastric junction NEC, which was difficult to diagnose, that has achieved relatively long-term survival with multidisciplinary treatment centered on nivolumab. A man in his 60s was initially diagnosed with an advanced esophagogastric junction squamous cell carcinoma (SCC). The lymph node metastasis was detected in the regional lymph nodes and para-aortic region. We diagnosed the patient with T3, N3, M1 (Lym), stage IVB, and administered systemic chemotherapy. Due to the failure of first-line, fluorouracil, and cisplatin therapy, we administered nivolumab as the second-line therapy. This therapy demonstrated partial response, so we performed conversion surgery, however the postoperative diagnosis was NEC. Three years after treatment initiation, a single lymph node metastasis has recurred, which is under control with nivolumab and radiation therapy. However, 4.5 years after the start of treatment, with the advent of immune-related adverse events (irAE), nivolumab was discontinued and the patient was placed on surveillance. Six months after that, metastasis to the hilar lymph node and adrenal gland was observed. Both times that recurrence/metastasis appeared, they occurred while nivolumab was being discontinued, suggesting its significant systemic anti-cancer effect. Therefore, nivolumab in particular may be an effective treatment for advanced esophageal NEC, and this case suggests that it may contribute to prolonged progression-free survival.

Gastric neuroendocrine carcinoma presenting complete durable response by nivolumab treatment for multiple metastases and radiotherapy to oligoprogressive metastasis

Gastric neuroendocrine carcinomas (NEC) are highly aggressive cancer with dismal prognosis. Platinum-based chemotherapy is used as the first-line treatment for this entity. However, there are no established therapeutic guidelines for platinum-resistant gastric NEC. We herein report a patient with metastatic gastric NEC who achieved durable and complete response to nivolumab with radiotherapy for oligoprogressive metastasis. A 70-year-old male patient had recurrences of resected gastric NEC, involving the liver and lymph nodes. His disease became refractory to cisplatin and etoposide combination therapy, after which he was treated with nivolumab. All the tumors showed marked shrinkage. However, 1 year after starting nivolumab, one metastatic lesion of the liver began to enlarge, and radiotherapy was performed to the lesion. Thereafter, a complete response was obtained, which has been maintained without any treatment for the past 2 years.

High T-cell infiltration in tumor tissue and younger age predict the response to pembrolizumab in recurrent urothelial cancer

Targeting the programmed cell death-1 signaling pathway has been approved for the anti-cancer therapy in several cancers including urothelial cancer. To determine predictive factors of the responsiveness to pembrolizumab in urothelial cancer patients, a retrospective study that used clinical information and paraffin-embedded samples obtained from patients diagnosed with urothelial cancer between 2015 and 2020 were performed. Seventeen patients who underwent total cystectomy or nephroureterectomy of the primary lesion and were treated with pembrolizumab for chemo-resistant disease were enrolled, and immunohistochemical analysis was performed. A key difference in the characteristics between the non-responder group and the responder group was the age of the patients (74 vs. 63 years, p = 0.0194). Although there was no statistically significant difference, the histological subtype with sarcomatoid and micropapillary components was only seen in the non-responder group, and squamous differentiation and lymph node metastasis were only seen in cases with a complete response. In the results of immunohistochemistry, the density of CD8-positive T-cells and Tregs was significantly increased in the responder group than in the non-responder group. In conclusion, younger age and a high number of tumor-infiltrating lymphocytes were predictive factors of a good response to immune checkpoint inhibitors, although further studies with more enrolled patients are necessary.