Notable response to nivolumab during the treatment of SMARCA4-deficient thoracic sarcoma: a case report

Area of Science:

• Oncology
• Genetics
• Immunotherapy

Background:

• SMARCA4-deficient thoracic sarcoma is a rare and aggressive malignancy.
• It typically presents as a mediastinal mass with a poor prognosis.
• Effective treatments for this condition remain largely unestablished.

Observation:

• A 76-year-old male patient was diagnosed with SMARCA4-deficient thoracic sarcoma.
• Initial treatments with cytotoxic chemotherapy were ineffective.
• The patient's provisional diagnosis was initially carcinoma of unknown primary, later corrected through genetic and immunohistochemical analysis.

Findings:

• Third-line therapy with nivolumab, an immune checkpoint inhibitor, resulted in marked and sustained tumor regression.
• This case represents the first documented instance of SMARCA4-deficient thoracic sarcoma responding positively to nivolumab.
• Panel-based cancer gene screening and immunohistochemistry were crucial for accurate diagnosis.

Implications:

• Immune checkpoint inhibitors, such as nivolumab, show potential as therapeutic candidates for SMARCA4-deficient thoracic sarcoma.
• This finding opens new avenues for treating this rare and previously difficult-to-treat cancer.
• Further research into immunotherapy for SMARCA4-deficient tumors is warranted.