Lung squamous cell carcinoma responding to nivolumab retreatment six years after initial treatment: A case report.

A 61-year-old man presented to our hospital with a chief complaint of chronic cough. He was diagnosed with lung squamous cell carcinoma at clinical stage cT2aN3M1a. He received chemotherapy up to the fourth line, but both the primary tumor and lymph node metastases increased in size. Nivolumab, administered as the fifth line, resulted in a complete response (CR) that continued for 2 years and 8 months. Treatment was stopped due to the appearance of common terminology criteria for adverse events grade 1 pneumonitis. He was followed up without treatment for 3 years and 8 months, but a left supraclavicular fossa lymph node metastasis appeared. Retreatment with nivolumab was initiated, and the patient achieved CR again. One year and 6 months after retreatment, CR was maintained with nivolumab. This case represents a rare instance in which nivolumab yielded a significant response after a prolonged immune checkpoint inhibitor (ICI)-free interval. Our experience has shown that the long-term response to ICIs may deteriorate in the future. Therefore, retreatment with ICIs may be effective when the initial therapy is successful.

Disinfection and monitoring of Mycobacterium avium complex in the environment: A novel approach to the management of hot tub lung.

A 45-year-old man visited our hospital with a chronic cough and breathing difficulties. Chest computed tomography revealed diffuse granular shadows. Mycobacterium avium (M. avium) was cultured from bronchoalveolar lavage fluid (BALF). Surgical lung biopsy revealed non-necrotizing granulomas, and M. avium-specific PCR was positive in the tissue. M. avium was also cultured in a sample from the inlet of the patient's bathtub. Mycobacterium avium tandem repeat variable-number tandem-repeat loci (MATR-VNTR) analysis confirmed that the M. avium cultured from BALF and the bathtub inlet had identical allele profiles. The patient's symptoms and oxygenation improved while the patient was in hospital, presumably because of lack of ongoing exposure to M. avium. He was diagnosed with hot tub lung. We advised the patient to avoid bathing to avoid re-exposure. However, the patient was unwilling to follow this advice. Therefore, his bathtub and pipework were disinfected by heating them to over 70 °C. We confirmed that the disinfection has been successful by repeated culture of environmental samples. Three months after resuming bathtub use, the patient's symptoms resolved, and the pulmonary shadows seen on the initial radiography did not recur. For the treatment of hot tub lung, disinfection of M. avium complex in the environment should be considered and the environment should be monitored to confirm eradication.

Cytokine Release Syndrome More than Two Years after Pembrolizumab Introduction.

A 71-year-old man with advanced lung adenocarcinoma was treated with carboplatin, pemetrexed, and pembrolizumab in June 2020. Pemetrexed and pembrolizumab maintenance therapy were continued until November 2022. A fever and severe fatigue occurred in December 2022; however, the cause of the infection was inconclusive based on the patient's symptoms, imaging findings, and culture tests. Although the patient was administered antibiotics, his general condition worsened. Considering the possible diagnosis of immune-related cytokine release syndrome (CRS), the patient was administered prednisolone (1 mg/kg/day) and showed improvement. In conclusion, CRS can occur even long after the initial administration of immune checkpoint inhibitor therapy.

Pure Red Cell Aplasia Induced by Atezolizumab in a Patient with Small-Cell Lung Cancer Successfully Treated with Steroid Therapy: A Case Report.

Introduction: Combination therapy of atezolizumab and chemotherapy has become the standard treatment for small-cell lung cancer. Immune-related adverse events (irAEs) can occur during immune checkpoint inhibitor administration. A few reports exist on pure red cell aplasia (PRCA) as an irAE after atezolizumab treatment. PRCA is characterized by normocytic-normochromic anemia, a marked decrease in reticulocytes, and a decrease in bone marrow erythroblasts. Here, we report a case of atezolizumab-induced PRCA. Case Presentation: A 69-year-old male patient was brought to the emergency department with the chief complaint of seizures. Multiple metastatic brain tumors and a mass suspected to be the primary lesion in the right hilar region were observed. After a brain biopsy, he was diagnosed with small-cell lung cancer (cT1cN0M1c stage IVB). He received four courses of carboplatin, etoposide, and atezolizumab in combination with whole-brain irradiation, which led to a partial response. After six courses of atezolizumab maintenance therapy, severe anemia (hemoglobin, 3.4 g/dL) was observed. PRCA induced by atezolizumab was diagnosed using a bone marrow biopsy performed during red blood cell transfusion. Treatment was started with prednisolone 25 mg/day (0.5 mg/kg/day). Anemia improved, and the dose was gradually reduced to 5 mg/day. Conclusion: Reports of PRCA as an irAE are rare but important; hence, we reported this case.