Preclinical Tumor Growth Delay Is More Reliable from Imaging-Based Rather than Manual Caliper Volume Measurements

Area of Science:

• Oncology
• Preclinical Research
• Medical Imaging

Background:

• Tumor growth delay (TGD) is a key metric in preclinical cancer research.
• Manual caliper measurements are standard for assessing TGD in animal models.
• Reliability of caliper measurements versus imaging is crucial for accurate intervention evaluation.

Purpose of the Study:

• To compare the reliability of caliper-based versus MRI-based volumetrics for assessing tumor growth delay.
• To evaluate the accuracy of normalized tumor growth delay (NTGD) rates derived from both methods.

Main Methods:

• A 4T1 murine breast cancer model was used with immunotherapy and radiotherapy.
• Tumor volumes were measured using manual calipers and MRI scans.
• NTGD rates were calculated from both caliper and MRI volumetric data.

Main Results:

• Averaged caliper volumes showed good correlation with MRI volumes (r=0.897).
• However, NTGD rates derived from caliper measurements did not correlate with MRI-derived rates.
• Significant discrepancies were observed, with only 15% of caliper NTGD rates within 10% of MRI rates.

Conclusions:

• Caliper-based NTGD is not a reliable measure of treatment response in preclinical studies.
• MRI-based volumetrics provide a more accurate and verifiable assessment.
• Medical imaging should replace caliper estimates for preclinical oncologic intervention evaluation.