Contrast-enhanced MRI and PET-CT in the evaluation of patients with suspected local recurrence of rectal carcinoma

Abstract

Contrast-enhanced MRI and PET-CT can help in the detection of local recurrence of rectal cancer, even though their roles in early detection remains debatable, as the value of these techniques in current surveillance protocols is still to be defined.

MRI of Rectal Cancer: An Overview and Update on Recent Advances

“…Enhancement in tumoral tissue has been shown to occur earlier and to be more intense and heterogeneous than enhancement in benign posttreatment fibrosis [86,87]. Besides its high diagnostic performance for the identification of distant metastatic disease in recurrent rectal cancer (sensitivity, 91%; spec-ificity, 83%) [88], PET/CT has also shown high sensitivity (89-94%) and variable specificity (69-94%) for diagnosing the local recurrence on the basis of the shape, location, and intensity of tracer uptake [88][89][90]. Biopsy is indicated whenever imaging or clinical findings are equivocal and the diagnosis of recurrent disease cannot be confirmed.…”

FDG-avid presacral soft tissue mass in previously treated rectal cancer: Diagnostic outcome and additional value of MRI, including diffusion-weighted imaging

“…However, it was unclear what type of surgery was performed in these 10 patients and if they underwent additional radiation therapy [5]. Yet more recent work reported the PPV of FDG-PET/CT to be only 48.1% based on a series of 60 patients with suspicious findings at follow-up CT after curative-intent surgery [11], although this study did not perform a separate analysis for presacral lesions.…”

“…With regard to the recent literature on the role of MRI in this setting, one study included only 11 presacral recurrences without any patients with benign presacral tissue [6], another study included only three presacral recurrences without separately reporting on the value of MRI for presacral space assessment [7], and two other studies mixed patients with presacral lesions with lesions elsewhere in the pelvis [8,11]. One recent study that investigated 47 integrated FDG-PET/MRI examinations in 46 patients, reported sensitivity, specificity, PPV, and NPV of 94%, 94%, 97%, and 90%, respectively [12].…”

Early Detection of Colorectal Cancer Recurrence in Patients Undergoing Surgery with Curative Intent: Current Status and Challenges

“…In prospective data comparing MRI with PET for local recurrence of rectal cancer (using histological biopsy as the gold standard), sensitivity, specificity, positive and negative predictive value and accuracy were 86.7%, 68.9%, 48.1%, 93.9% and 73.3% for contrast-enhanced MRI and 93.3%, 68.9%, 50%, 96.9% and 75% for PET-CT. 56 Unfortunately, there were only 39 cases, and the role for early detection was debatable. Other comparisons report overall diagnostic accuracy for PET-CT at 91% (sensitivity 86%, specificity 96%) and 83% for MRI (sensitivity 72%, specificity 93%), respectively; though PET-CT appears to be better for nodal disease and both equal for organ involvement.…”