Introduction: Immune checkpoint inhibitors (ICIs) have considerably improved the prognosis of solid tumors. However, this class of medications can cause immune-related adverse events, which represent a distinct spectrum of adverse events in cancer treatment. Case Report: Here we present a case of immune-related neutropenia (irN) that occurred in a 47-year-old man with metastatic clear cell renal cell carcinoma (ccRCC). During the 18 months of nivolumab monotherapy, severe neutropenia occurred. Buccal mucosal aphthous ulcers and antineutrophil cytoplasmic antibody positivity concurrently emerged with neutropenia. The patient was diagnosed with irN after a comprehensive evaluation ruled out all other likely causes. Management and outcome: Neutropenia improved with corticosteroids, but reoccurred with the introduction of nivolumab. During the approximately nine-month follow-up period after nivolumab treatment was permanently discontinued due to neutropenia, there was no disease progression. Discussion: IrN associated with nivolumab treatment for metastatic ccRCC is uncommon. The pathophysiology of irN is not entirely understood. Corticosteroids are one of the most commonly used drugs for the treatment of irN. As ICIs become more widely used, medical oncologists will encounter this side effect more frequently.

Ewing sarcoma (ES) mainly affects children and adolescents; thus, treatment protocols for adult patients are adapted from pediatric protocols. Long treatment durations often lead to treatment discontinuation for adults. This single-center retrospective study evaluated real-world outcomes and compliance with standard chemotherapy regimens in adult patients with localized ES. Adult patients diagnosed with localized ES who underwent curative intent treatment between 2007 and 2022 were retrospectively analyzed. Patients who were intended to receive the vincristine, adriamycin, and cyclophosphamide (VAC)/(ifosfamide, etoposide) regimen, consisting of 18 cycles along with local treatment, were included in this study. Adherence to the treatment protocol and outcomes were evaluated. Event-free survival (EFS) and overall survival were calculated, and predictors of treatment completion were assessed. A total of 31 patients were analyzed. Median age was 28 years (range, 18–71 yr); 17 patients were male (54.8%) and 14 were female (45.2%). Fourteen (45.1%) patients underwent surgery, 10 (32.3%) received radiotherapy, and 7 (22.5%) received both treatments. Eighteen (58.1%) patients completed 18 chemotherapy cycles. Patients undergoing surgical resection were likelier to complete all the chemotherapy cycles (odds ratio: 0.117, 95% confidence interval: 0.016–0.835). The estimated 5-year EFS and overall survival rates were 37% and 58%, respectively. Multivariate analysis identified a neutrophil-lymphocyte ratio ≥ 5 as an independent predictor of EFS (hazard ratio: 4.50, 95% confidence interval: 1.52–13.30, P = .006). Compliance with the 51-week-long vincristine, adriamycin (doxorubicin), and cyclophosphamide/ifosfamide and etoposide chemotherapy regimen remains a critical issue for adult patients. Our findings suggest that surgical resection may be associated with better compliance with the chemotherapy protocol, and a neutrophil-lymphocyte ratio of ≥5 may be linked to poorer outcomes.

PURPOSE: Primary bone sarcomas, including osteosarcoma, chondrosarcoma, and Ewing sarcoma, have poor prognoses, with 5-year overall survival (OS) rates of < 20%-30% in metastatic or recurrent disease. Although tyrosine kinase inhibitors (TKIs) targeting angiogenic and oncogenic pathways have shown efficacy in phase II trials, there is a lack of supporting real-world data. This study aimed to evaluate the efficacy and safety of TKI use in patients with advanced bone sarcomas in a real-world setting. MATERIALS AND METHODS: This multicenter, retrospective study included 72 patients with advanced or metastatic osteosarcoma, chondrosarcoma, or Ewing sarcoma who received at least one TKI (regorafenib, pazopanib, sorafenib, or cabozantinib) at multiple centers in Türkiye. Progression-free survival (PFS) and OS were estimated using the Kaplan-Meier method. Adverse events were recorded and graded according to standard criteria. RESULTS: The median age was 28.5 years (range, 17-72 years), and 62.5% (n = 45) of the patients were male. The most frequently used TKIs were regorafenib (n = 31, 43.1%) and pazopanib (n = 22, 30.6%); in the majority of patients (n = 68, 94.4%), TKIs were used as second-line or subsequent treatment. The median PFS for the entire cohort was 4.8 months (95% CI, 3.05 to 6.48), and the median OS was 9.9 months (95% CI, 6.48 to 13.25). In histologic subgroup analyses, the median PFS was 4.4 months for osteosarcoma, 4.8 months for chondrosarcoma, and 5.4 months for Ewing sarcoma. Adverse events were observed in 50% (n = 36) of patients, and 89.2% (n = 58) of these were grade 1-2. Dose reduction was required in 27.8% (n = 20) of patients, and permanent treatment discontinuation due to toxicity was necessary in 6.9% (n = 5) of patients. CONCLUSION: In this real-world cohort, although TKIs were associated with limited survival outcomes, they had an acceptable safety profile in patients with advanced bone sarcomas. These findings are consistent with the results of phase II studies and suggest that TKIs may be a treatment option for patients who have disease progression after standard therapies.