Role of Adjuvant Chemotherapy After Surgical Resection of Paraaortic Lymph Node Metastasis from Colorectal Cancer-A Multicenter Retrospective Study.

Background: Surgical removal of metastasized paraaortic lymph nodes (PALNs) can prolong the survival of certain patients with colorectal cancer (CRC). However, the role of postoperative chemotherapy in such patients remains unknown.

Patients And Methods: This multicenter retrospective study examined 97 patients with PALN metastasis from CRC who underwent surgical resection at 36 centers in Japan between 2010 and 2015. On the basis of adjuvant chemotherapy (AC) after the lymphadenectomy, patients were classified into non-AC and AC groups (27 and 70 patients, respectively). After the exclusion of patients receiving irinotecan, the latter group was further categorized into 5-fluorouracil (5-FU) and oxaliplatin (L-OHP) subgroups (14 and 52 patients, respectively) according to the use of L-OHP. Background characteristics and postoperative survival were compared among the groups.

Results: Marked differences were not seen in background characteristics, except for neoadjuvant treatment, between the non-AC and AC groups. The AC group exhibited better recurrence-free survival (RFS; p = 0.009) and overall survival (OS; p = 0.040 by the Wilcoxon test) than the non-AC group. However, RFS and OS of the 5-FU group did not differ from those of the L-OHP group (p = 0.73 and p = 0.92 by the Wilcoxon test, respectively).

Conclusions: AC may be associated with improved prognosis of patients after the removal of PALN metastasis from CRC, but L-OHP did not offer additional survival benefits. Prospective studies comparing non-AC with 5-FU- and L-OHP-based AC are needed to confirm these findings.