Association of Pelvic Structure Involvement and Tumor Morphology at MRI with Prognosis Following Resection in Locally Recurrent Rectal Cancer

Abstract

Purpose To determine the influence of location, extent of tissue invasion, and tumor morphology at MRI on the resectability of locally recurrent rectal cancer (LRRC) and postresection oncologic outcomes of LRRC. Materials and Methods This retrospective observational study included consecutive patients diagnosed with LRRC who underwent surgery with curative intent at the Catharina Hospital Eindhoven and Karolinska University Hospital Stockholm between January 2003 and December 2017. Two expert radiologists reviewed available MR images while adhering to a standardized reviewing checklist. The effect of pelvic structure involvement, tumor morphology on the primary outcome of resection margin status, and secondary outcomes of overall survival and disease-free survival were assessed using univariable and multivariable logistic regression and Cox proportional hazard analyses. Results The final analysis included 328 patients with LRRC (mean age ± SD, 64.9 years ± 9.6; 126 female, 202 male). Resection margins were negative in 217 (66.2%) patients and positive in 111 patients (33.8%). Tumor size, tumor type, and border type on MR images were all associated with resectability. Central recurrences were associated with the lowest likelihood of positive resection margins (odds ratio [OR], 0.45; 95% CI: 0.28, 0.71; P < .001), whereas lateral recurrences were associated with the highest likelihood (OR, 2.00; 95% CI: 1.25, 3.19: P = .004). Similarly, central recurrences were associated with better disease-free survival compared with lateral recurrences (hazard ratio [HR], 0.69; 95% CI: 0.53, 0.90; P = .006 vs HR, 1.49; 95% CI: 1.14, 1.94; P = .003, respectively). Similar findings were observed after correcting for resection margin status. Conclusion Standardized MRI assessment of tumor characteristics in patients with LRRC resulted in the identification of specific prognostic factors. Central compartment involvement and well-defined tumors were associated with improved prognosis, whereas lateral compartment involvement and fibrotic spiculated tumors were associated with a worse prognosis after surgical resection. Keywords: Rectum, MR-Imaging, Abdomen/GI, Oncology, Surgery, Locally Recurrent Rectal Cancer, Tumor Biology Supplemental material is available for this article. © RSNA, 2025.

Keywords: Abdomen/GI; Locally Recurrent Rectal Cancer; MR-Imaging; Oncology; Rectum; Surgery; Tumor Biology.

Graphical abstract

Figure 1:

Flowchart of patient selection. LRRC = locally recurrent rectal cancer.

Figure 2:

T2-weighted MR images of primary involved compartments in locally recurrent rectal cancer. (A) Non–contrast-enhanced T2-weighted sagittal MR image shows a solid tumor type in a 58-year-old male patient. (B) Non–contrast-enhanced T2-weighted transverse MR image of a mucinous tumor type in a 48-year-old male patient. (C) Non–contrast-enhanced T2-weighted transverse MR image of a fibrotic tumor type in a 75-year-old-male patient. Tumors are circled in blue.

Figure 3:

Graph shows disease-free survival of patients with radical resection (R0) of lateral and nonlateral locally recurrent rectal cancer (LRRC).

Figure 4:

Graph shows disease-free survival of patients with radical resection (R0) of central and noncentral locally recurrent rectal cancer (LRRC).

Figure 5:

T2-weighted MR images of tumor types in locally recurrent rectal cancer. (A) Non–contrast-enhanced T2-weighted transverse MR image of a well-defined tumor border in a 73-year-old-male patient. (B) Non–contrast-enhanced T2-weighted transverse MR image of a spiculated or irregular tumor border in an 88-year-old male patient. Tumors are circled in blue.

Figure 6:

T2-weighted MR images of border types in locally recurrent rectal cancer. (A) Non–contrast-enhanced T2-weighted transverse MR image of central compartment involvement in a 67-year-old male patient. (B) Non–contrast-enhanced T2-weighted transverse MR image of anterior compartment involvement in a 77-year-old male patient. (C) Non–contrast-enhanced T2-weighted sagittal MR image of posterior compartment involvement in a 46-year-old male patient. (D) Non–contrast-enhanced T2-weighted transverse MR image of lateral compartment involvement in a 58-year-old male patient. Tumors are circled in blue.