Long-Term Outcomes of Surgical Resection of Pathologically Confirmed Isolated Para-Aortic Lymph Node Metastases in Colorectal Cancer: A Systematic Review

Simple Summary Para-aortic lymph node (PALN) metastases represent patterns of initial recurrence in only 2-6% CRC patients. Lack of consensus has impaired an unambiguous statement for PALN recurrence resection. Our systematic review identified 59.4-68% 3-year OS rate and 53.4-87.5% 5-year OS rate, with a 25-84 months median OS, 26.3-61% 3-year DFS rate and 0-60.5% 5-year DFS rate, with a 14-24 month median DFS, in patient undergoing isolated PALNM resection. Overall, 62.1% re-recurrence rate ranged from 43.8% to 100%. Although PALNMs resection in CRC patients may be considered a feasible and beneficial option, no conclusions or recommendations can be provided, taking into account the current evidence. Further randomized, possibly multicenter trials are strongly recommended and mandatory in order to confirm our results and clearly identify patient selection criteria. Background: Para-aortic lymph node (PALN) metastases represent patterns of initial recurrence in only 2-6% CRC patients, after an estimated 23-28 month time interval. An increasing trend towards curative surgery has been witnessed in patients presenting with controlled PALN recurrence. Nevertheless, lack of consensus has impaired an unambiguous statement for PALN recurrence resection. Methods: We performed a systematic literature review following the Preferred Reporting Items for Systematic Reviews and Meta-Analyzes (PRISMA) guidelines, which led us to gain deeper insight into the prognostic factors and long-term outcomes after resection for synchronous or metachronous pathologically confirmed CRC isolated para-aortic lymph node metastases (PALNM). Pubmed/MEDLINE, Embase, Scopus, Cochrane Library and Web of Science databases were used to search all related literature. Results: The nine articles included covered a study period of 30 years (1988-2018), with a total of 161 patients. At presentation, most primary CRCs were located in the colon (74%) and 95.6%, 87.1% and 76.9% patients had T3-T4, N1-N2 and well/moderately differentiated CRC, respectively. We identified a 59.4-68% 3-year OS rate and 53.4-87.5% 5-year OS rate, with a 25-84 months median OS, 26.3-61% 3-year DFS rate and 0-60.5% 5-year DFS rate, with a 14-24 month median DFS. Overall, 62.1% re-recurrence rate ranged from 43.8% to 100%. Conclusions: Although PALNMs resection in CRC patients may be considered a feasible and beneficial option, no conclusions or recommendations can be made taking into account the current evidence. Therefore, further randomized, possibly multicenter trials are strongly recommended and mandatory if we want to have our results confirmed and patient selection criteria clearly identified.