Current Imaging Modalities Understage One-Third of Patients with Stage I Rectal Cancer: Implications for Treatment Selection.

Accurate preoperative clinical staging is essential to optimize the treatment of rectal cancer. Primary surgical resection is typically indicated for stage I disease, whereas neoadjuvant therapy is recommended for stages II and III. The objective of this study is to examine the accuracy of clinical staging using current imaging modalities in predicting pathologic stage and, thus, selecting appropriate treatment. Adult patients with nonmetastatic rectal cancer who underwent primary surgical resection were identified from the National Cancer Database between 2006 and 2014. Data on clinical and pathologic staging was obtained. Kappa index was used to determine the correlation between clinical and pathologic staging. A total of 13,175 patients were identified. The correlation between clinical and pathologic staging was 69 per cent for stage I (31% upstaged) (Kappa 0.54, P < 0.001). One-third of patients who were clinically staged as stage I, and were therefore treated with primary surgical resection, had pathologic stage II or III disease. Based on their clinical staging, those patients did not receive the neoadjuvant therapy recommended by present guidelines. Where accurate clinical staging is in doubt, oncologists should carefully examine the quality of staging modality and perhaps consider multimodal imaging using both endorectal ultrasound and MRI.