Quantitative parameters of magnetic resonance imaging cannot predict human epidermal growth factor receptor 2 (HER2) status in rectal cancer.

PURPOSE

To retrospectively investigate whether magnetic resonance imaging (MRI) quantitative parameters can differentiate human epidermal growth factor receptor 2 (HER2) status in rectal cancer.

MATERIALS AND METHODS

This study included 89 patients with surgically confirmed rectal cancer who underwent preoperative MRI from June 2014 to May 2019. Patients were divided into three groups: HER2 negative (HER2-Neg); HER2-low expression (HER2-L); and HER2 positive (HER2-Pos). Quantitative perfusion parameters derived from dynamic contrast-enhanced MRI (DCE-MRI) Tofts model (pharmacokinetic blood dual compartment model) were listed as follows: volume transfer constant (K), rate constant (K), and extracellular volume ratio (V). The mean, minimum, and maximum apparent diffusion coefficient (ADC) values at standard (800 s/mm) b-values were obtained with diffusion-weighted imaging (DWI). Clinicopathologic characteristics and quantitative parameters were compared by Fisher's exact test and one-way analysis of variance (ANOVA), respectively.

RESULTS

The 89 patients included 52 (58.4%) with HER2-Neg, 31 (34.8%) with HER2-L, and 6 (6.8%) with HER2-Pos states. Fisher's exact test showed that clinicopathologic characteristics among the three groups were not significantly different (p = 0.281 to 1.000). Likewise, there were no associations between HER2 status and any quantitative parameters, including K (p = 0.296), K (p = 0.290), V (p = 0.184), ADC (p = 0.181), ADC (p = 0.143), or ADC (p = 0.058).

CONCLUSION

Quantitative perfusion parameters (K, K, V) and ADC values were not able to discriminate HER2 status in patients with rectal cancer or evaluate treatment response in real time.