Predicting recurrence and metastasis of stage II/Dukes' B colorectal cancer without lymph node metastasis

This study was designed to compare the prediction of recurrence based on detection of occult neoplastic cells (ONCs) in lymph nodes or by using high-risk criteria for recurrence/metastasis in patients with Dukes' B colorectal cancer. Prediction of recurrence based on the detection of ONCs had a sensitivity of 59.1% (13/22), a false-positive rate of 7.8% (8/102), a specificity of 92.2% (94/102), and a negative predictive value (NPV) of 91.3% (94/103). Prediction of recurrence based on positivity for at least 2 of the 3 high-risk criteria had a sensitivity of 90.9% (20/22), a false-positive rate of 49.0% (50/102), a specificity of 51.0% (52/102), and an NPV of 96.3% (52/54). Among the 21 patients in whom ONCs were detected, prediction of recurrence based on the presence of all 3 high-risk criteria including ONCs had a sensitivity of 84.6% (11/13) and a positive predictive value (PPV) of 78.6% (11/14). These results suggest that colorectal cancer is unlikely to recur in patients without ONCs, while recurrence is likely in patients who fulfill 2 or more of the high-risk criteria. Accordingly, a combination of these parameters may be useful for the early prediction of recurrence/metastasis to assist in the choice of postoperative systemic chemotherapy.