Relationship between apparent diffusion coefficient values and clinicopathologic features in rectal cancer: a cross-sectional study.

BACKGROUND

The prognosis of rectal cancer is closely related to its clinicopathologic features. Accurate preoperative assessment of these features is crucial for treatment planning and prognosis prediction. The apparent diffusion coefficient (ADC), derived from diffusion-weighted imaging (DWI), has shown potential as a noninvasive imaging biomarker for evaluating tumor characteristics. This study aimed to explore the relationship between ADC values and the clinicopathological features of rectal cancer.

METHODS

We retrospectively recruited 97 eligible patients with rectal adenocarcinoma who underwent magnetic resonance imaging (MRI) and surgical resection at our institution between January 2023 and December 2023. Each patient was evaluated for the presence of extramural vascular invasion (EMVI) or circumferential resection margin (CRM) on MRI, and the mean (ADC), minimum (ADC), and maximum (ADC) ADC values were calculated. Moreover, the relationship between the ADC values and clinicopathological features, including tumor stage, histologic grade, lymphovascular invasion, perineural invasion, and lymph node metastasis, were statistically analyzed.

RESULTS

Among 97 patients with rectal cancer, the mean age was 61.40±10.46 years and 60 (61.9%) were males. ADC, ADC, and ADC were significantly lower in patients with EMVI or CRM than in those without EMVI or CRM (P<0.05). Pathologic T1-2 staging exhibited higher ADC (0.79±0.26 0.61±0.22, P=0.001), ADC (0.71±0.26 0.55±0.22, P=0.002) and ADC (0.89±0.26 0.75±0.22, P=0.004) compared with T3-4 staging. Highly and moderately differentiated tumors had higher ADC, ADC, and ADC than less-differentiated tumors (P<0.05). Patients with lymphovascular invasion, perineural invasion, and lymph node metastasis showed significantly lower ADC, ADC, and ADC than those without these conditions (P<0.05). ADC, ADC and ADC were negatively correlated with EMVI (r=-0.334, -0.340, -0.302), CRM (r=-0.362, -0.414, -0.276), pathologic T-stage (r=-0.324, -0.313, -0.276), histologic grade (r=-0.353, -0.352, -0.289), lymphovascular invasion (r=-0.405, -0.384, -0.421), perineural invasion (r=-0.428, -0.407, -0.265), and lymph node metastasis (r=-0.347, -0.316, -0.268) in rectal cancer.

CONCLUSIONS

ADC values were negatively associated with different clinicopathological features of rectal cancer, suggesting their potential role as noninvasive imaging markers for preoperative tumor assessment.