Risk factors for paraaortic lymph-node recurrence in colorectal cancer

Background: The paraaortic lymph-node (PALN) is a relatively uncommon metastasis as a first site of recurrence following colorectal cancer (CRC) surgery. Localized and resectable PALN recurrence has the potential of long-term survival by curative resection. We evaluated the risk factors for the recurrence of PALN following curative surgery in patients with CRC in a pooled analysis of two large randomised control studies. Patients and Methods: Individual patient data from the Japanese Foundation for Multidisciplinary Treatment of Cancer clinical Trials 7 and 15 were pooled for this analysis. We included total 4459 patients who had stage I-III colorectal cancer and underwent curative resection with over D2 lymph node dissection. Results: Recurrent PALN occurred in 0.7% of all patients (30/4459). Of the 30 patients with recurrent PALN, 19 had PALN alone, whereas 11 had a recurrence in at least one other organ in addition to PALN. PALN recurrence occurred after the 3-year postoperative period in 10 patients (33%). In multivariate analysis, lymph node involvement was the only independent predictor of recurrent PALN (hazard ratio, 2.670; p = 0.0106). Conclusions: Our findings clarify the risk factors for PALN recurrence in stage I–III CRC who undergo curative resection. These results will be useful to identify optimal subgroups for high risk of PLAN recurrence.