Computed Tomography in the Postoperative Surveillance of Stage III Colorectal Cancers Receiving Adjuvant Chemotherapy

Abstract

Purpose. Colorectal cancer (CRC) is the most common malignancy in Taiwan. Approximately 30-50% of CRC patients receiving radical resection will eventually develop postoperative relapse. Surveillance for early detection of postoperative relapse is the ideal goal, and computed tomography (CT) scan is the crucial tool for such surveillance for stage III CRC patients administrated with adjuvant chemotherapy; however, the routine role of CT scan in the post-chemotherapeutic surveillance in local recurrence or distant metastasis of these patients in the clinical practice remains largely unknown.Methods. From January 2008 to February 2011, a retrospective analysis of 115 stage III CRC patients undergoing primary lesion resection following by adjuvant chemotherapy was investigated. The sensitivity, specificity, positive predictive value, negative predictive value and accuracy of CT scan for the diagnosis of postoperative local recurrence and distant metastasis were analyzed.Results. There were no significant differences between colon and rectal cancer patients in age (p=0.798), gender (p=0.242), tumor size (p=0.288), tumor depth (p=0.059), and lymph node metastasis (p=0.557).The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of CT scan for colon cancer or rectal cancer patients in the diagnosis of distant metastasis are similar. However, the sensitivity of CT scan in the diagnosis of local recurrence in colon cancer (22.2%) and rectal cancer (50%) was relatively low.Conclusion. Our study showed that the sensitivity for diagnosis of local recurrence in colon and rectal cancer patients is prominently lower than that of distant metastasis by CT scan. Therefore, more precise image studies in the surveillance may be mandatory to improve accurate detection of local recurrence for CRC patients following adjuvant chemotherapy.