Predictive value of lesion morphology in rectal cancer based on MRI before surgery

Area of Science:

• Radiology
• Oncology
• Surgical Pathology

Background:

• Rectal cancer staging relies on accurate prediction of adverse prognostic indicators.
• MRI offers a non-invasive method to assess tumor characteristics and predict outcomes.

Purpose of the Study:

• To investigate the correlation between MRI morphology of primary rectal cancer and key adverse prognostic factors.
• To evaluate the predictive value of specific MRI features for extramural vascular invasion (EMVI), metastasis, and local recurrence.

Main Methods:

• Retrospective analysis of 153 rectal cancer patients.
• Evaluation of imaging factors (e.g., nodular projection, cord sign, irregular nodules, peritoneal reflection invasion, extramural depth) and histopathological data.
• Univariate and multivariable logistic regression to determine significant predictors.
• Construction and validation of a nomogram for predicting EMVI.

Main Results:

• Nodular projection (NP), cord sign (CS), irregular nodules (IN), maximal extramural depth (EMD), MRI-detected EMVI (mEMVI), and circular infiltration were significantly associated with adverse prognostic indicators.
• mEMVI predicted synchronous metastasis, while peritoneal reflection invasion (PRI) and mEMVI predicted local recurrence.
• A nomogram for predicting preoperative EMVI showed high accuracy (C-index 0.868, accuracy 81.7%).

Conclusions:

• Specific MRI features, including NP, CS, IN, large EMD, mEMVI, and circular infiltration, are significant predictors of adverse prognostic indicators in rectal cancer.
• The developed nomogram demonstrates good predictive performance for preoperative EMVI.
• mEMVI and PRI are identified as risk factors for synchronous metastasis and local recurrence, respectively.