Extended-Interval Immunotherapy in Advanced Lung Cancer: A Case Report.

Lung adenocarcinoma frequently presents at an advanced stage with metastases, including the brain. Advances in immunotherapy have improved survival rates; however, challenges remain regarding optimal dosing schedules and the management of immune-related adverse events (irAEs). This case report aims to demonstrate that a less frequent immunotherapy regimen, administered every six weeks, in certain clinical scenarios may maintain durable disease stabilization while potentially reducing clinically significant toxicities. These findings support further evaluation of modified-dose immunotherapy regimens in clinical trials. We retrospectively reviewed the clinical course of a patient with advanced lung adenocarcinoma with brain and contralateral lung involvement over a 14-month period. The patient underwent biopsy confirmation, immunotherapy with atezolizumab, stereotactic radiosurgery for oligometastatic brain lesions, and subsequent therapeutic adjustments, including antibiotic treatment for pneumonia and immunotherapy regimen modifications to manage irAEs. The patient ultimately received a total of nine cycles of atezolizumab. Initial atezolizumab treatment (administered every three weeks) achieved disease stabilization (RECIST 1.1: -26.4%). The immunotherapy interval was adjusted to every six weeks during the treatment course to mitigate toxicities. Disease control was maintained with manageable irAEs, improving the patient's quality of life. This case supports the hypothesis that, in individualized cases, a six-week immunotherapy schedule could provide durable responses in advanced lung adenocarcinoma with fewer life-threatening irAEs. These findings could inform future trials to assess the broader applicability of extended immunotherapy regimens.