Tumor mutational burden is not predictive of cytotoxic chemotherapy response

Area of Science:

• Oncology
• Genomics
• Cancer Research

Background:

• High tumor mutational burden (TMB) is linked to immunotherapy response.
• The relationship between TMB and cytotoxic chemotherapy effectiveness is not well understood.
• This study investigates TMB's role in predicting outcomes for solid tumors treated with chemotherapy.

Purpose of the Study:

• To determine if TMB predicts clinical benefit in patients receiving cytotoxic chemotherapy.
• To assess the correlation between TMB and progression-free survival (PFS) in solid tumors.
• To evaluate TMB as a predictive biomarker for chemotherapy response.

Main Methods:

• Retrospective analysis of 294 patients with solid tumors receiving cytotoxic chemotherapy.
• TMB was evaluated within one year of chemotherapy initiation.
• Clinical benefit and PFS were determined by reviewing electronic medical records and imaging.

Main Results:

• No significant difference in TMB was observed between patients who achieved clinical benefit (stable disease ≥6 months, partial response, or complete response) and those who did not.
• Progression-free survival (PFS) did not significantly differ between patients with low TMB (<10 mutations/Mb) and high TMB (≥10 mutations/Mb).
• This lack of association held true across specific cancer types including breast, lung, and gastrointestinal cancers.

Conclusions:

• Tumor mutational burden (TMB) is not a predictive biomarker for response to cytotoxic chemotherapy.
• TMB does not appear to influence clinical benefit or progression-free survival in patients undergoing chemotherapy for solid tumors.