Correlation between occult neoplastic cells in the lymph node sinuses and recurrence in patients with Dukes' C...

The aim of this study was to investigate whether it was possible to select patients with Dukes' C primary colorectal cancer who had a high risk of metastasis and recurrence. Among 434 patients who underwent surgical resection of primary colorectal cancer, 115 patients (26.5%) had Dukes' C cancer. Among them, 35 patients (30.45%) suffered from metastasis/recurrence postoperatively. Thirty-two patients with recurrence for whom complete follow-up was possible (recurrence group) and 32 patients who survived for at least 5 years without recurrence (non-recurrence group) were compared by immunohistochemical staining of resected lymph nodes for cytokeratin using two antibodies (AE1/AE3 and CAM 5.2). AE1/AE3 staining was positive in 93.85% of the recurrence group versus 68.85% of the non-recurrence group (p=0.0250), while CAM 5.2 staining was positive in 84.45% vs. 53.15%, respectively (p=0.0152). The occult neoplastic cell count (mean +/- SD) in the peripheral lymph node sinuses was 6.28+/-5.17 vs. 2.38+/-3.03 (p=0.0002) in the AE1/AE3-positive patients from the recurrence and non-recurrence groups, while it was 5.13+/-4.84 vs. 1.53+/-2.37 (p=0.0003) in the CAM 5.2-positive patients in each group. Accordingly, the immunohistochemical positivity rate for both AE1/AE3 and CAM 5.2, as well as the occult neoplastic cell count, were significantly higher in the recurrence group. These results suggest that patients with Dukes' C primary colorectal cancer who have a higher risk of recurrence can be selected by immunostaining of resected lymph nodes for cytokeratin.