Durable Response to Atezolizumab in Extensive-Stage Small-Cell Lung Cancer Leading to 60 Months Overall Survival: A Case Report

Abstract

Small-cell lung cancer (SCLC) remains a disease with poor prognosis, particularly in extensive-stage SCLC (ES-SCLC). Current standard-of-care treatment includes chemotherapy with platinum agents and etoposide plus immunotherapy with atezolizumab or durvalumab, which has achieved a mean overall survival of 12–13 months in clinical trials. However, long-term survival in ES-SCLC, even with the addition of immunotherapy, continues to be rare. We present the case of a middle-aged male patient diagnosed with ES-SCLC who was treated with four cycles of induction chemotherapy (carboplatin and etoposide) and atezolizumab, starting maintenance atezolizumab every 21 days thereafter, and thoracic radiotherapy. After 9 months, he experienced mild disease progression and was rechallenged with six cycles of carboplatin and etoposide with continued atezolizumab. Subsequent imaging showed near-complete disease resolution which has been sustained since. He has continued on maintenance atezolizumab since diagnosis and has achieved 60 months overall survival and 44 months progression-free survival. Throughout treatment, he has maintained a high functional capacity and only experienced one immune-related adverse event. Our patient is representative of a small subset who are capable of achieving durable responses to immunotherapy and his case highlights the need for further research to elucidate the clinical and biological factors driving this response.

Keywords

• small-cell lung cancer
• extensive-stage small-cell lung cancer
• durable response
• atezolizumab
• long-term survival