Relevant parameters for describing the oxygenation status of solid tumors

Area of Science:

• Oncology
• Biomedical Engineering
• Medical Physics

Background:

• Tumor tissue oxygenation (pO2) is highly heterogeneous across different tumor types.
• A single pO2 value is insufficient to describe the complex oxygenation status of solid tumors.
• Understanding tumor oxygenation is crucial for diagnosis, therapy, and predicting biological behavior.

Purpose of the Study:

• To identify and present essential distribution parameters for a comprehensive description of solid tumor oxygenation.
• To establish a standardized set of parameters for characterizing tumor pO2 heterogeneity.
• To provide metrics for assessing the biological and therapeutic relevance of tumor oxygenation.

Main Methods:

• Statistical analysis of pO2 distribution data from solid tumors.
• Identification of key statistical parameters (e.g., median, percentiles, interpercentile range) to describe pO2 distribution.
• Inclusion of biological parameters reflecting the impact of oxygen levels on tumor microenvironment and behavior.
• Consideration of quality parameters for assessing the reliability of pO2 measurements.

Main Results:

• Tumor pO2 distributions are often asymmetrically shifted towards lower values.
• Recommended statistical parameters include median, mean, 10th and 90th percentiles, minimum, maximum, and interpercentile range.
• Key biological parameters include the fraction of pO2 readings below critical thresholds (2.5, 5, and 10 mm Hg).
• Quality assessment requires reporting the fraction of negative pO2 readings and the most negative value.

Conclusions:

• A comprehensive description of solid tumor oxygenation necessitates a defined set of distribution parameters.
• These parameters include statistical measures, biologically relevant fractions of low pO2 values, and quality control metrics.
• Standardizing these parameters will improve the comparability and interpretation of tumor oxygenation studies.