Real-world data on microsatellite instability status in various unresectable or metastatic solid tumors

Area of Science:

• Oncology
• Biomarkers
• Cancer Genomics

Background:

• Microsatellite instability-high (MSI-H) is a predictive biomarker for immune checkpoint inhibitor (ICI) efficacy in advanced solid tumors.
• Understanding the precise frequency of MSI-H across various cancer types and patient demographics is crucial for effective ICI therapy planning.

Purpose of the Study:

• To investigate the actual frequency of MSI-H in a large cohort of diverse cancer samples examined in clinical practice.
• To analyze the variation in MSI-H frequency by cancer type, gender, and age.

Main Methods:

• Analysis of MSI test results from 26,469 diverse cancer samples collected between December 2018 and November 2019.
• Data included patient demographics (gender, age) and MSI test outcomes for 26,237 samples (99.1% completion rate).

Main Results:

• The overall frequency of MSI-H was 3.72% across all cancer types.
• MSI-H was significantly more prevalent in females (4.75%) than males (2.62%).
• Higher MSI-H frequencies were observed in patients younger than 40 (6.12%) and older than 80 (5.77%).
• MSI-H was detected in 30 cancer types, with high rates in endometrial (16.85%), small intestine (8.63%), and gastric (6.74%) cancers.

Conclusions:

• The frequency of MSI-H varies significantly across different cancer types, genders, and age groups.
• These real-world data provide valuable insights for optimizing the selection of patients for ICI treatment.
• The widespread detection of MSI-H across diverse malignancies underscores its broad relevance in cancer immunotherapy.