Indication: Presentation and evaluation of diagnostic procedures for the follow-up in patients with suspected local recurrence of rectal cancer.
Methods: Follow-up usually is performed using endoscopy and endosonography. Imaging techniques applied are also contrast enema as well as helical CT,MR imaging (MRI), and positron emission tomography (PET).
Results: The results demonstrate the difficulty of all available modalities to differentiate between early tumor recurrences from post-therapeutic alterations. Especially the differentiation of scar tissue and local tumor recurrence, the detection of lymph node as well as pulmonary or hepatic metastasis requires a large diagnostic effort with employment of various imaging modalities. Values determined for sensitivity and specificity for CT are 84% and 91% with a positive predictive value (PPV) of 78%. For MRI and PET the sensitivity are 94% and 98%,and the specificity 92% and 90% with a PPV of 93% for the PET.
Conclusion: The results demonstrate the increasing importance of CT and MRI in the follow-up of patients with rectal cancer and enable an accurate and early diagnosis through employment of new examination strategies and sequence protocols.PET remains an add-on examination in uncertain local lesions.