Abstract
BACKGROUND/AIM: Rapid progressive disease (RPD), accelerated tumour growth immediate after the initiation of immune checkpoint inhibitor therapy, has been reported in melanoma and lung cancer. Herein, we describe 3 cases of RPD during the initial phase of nivolumab treatment for metastatic renal cell carcinoma. PATIENTS AND METHODS: The first and second patients received nivolumab in the fourth-line setting. The third patient received nivolumab therapy as third-line treatment. RESULTS: The first patient developed severe respiratory failure due to carcinomatous lymphangiosis 14 days after initiation of nivolumab therapy. The second patient developed leg paraplegia due to rapid growth of the metastatic tumour at the sixth thoracic vertebrae 5 days later. The third patient developed grade 4 hypercalcemia due to RPD on day 3. CONCLUSION: Clinicians should be aware of RPD during the initial phase of nivolumab therapy, especially in patients with critical lesions in the late-line setting.