Long-term Outcome After Surgical Resection of Paraaortic Lymph Node Metastasis of Colorectal Cancer: A Multicenter Retrospective Study.

ABSTRACT

BACKGROUND: The significance of resection of paraaortic lymph node metastasis in colorectal cancer is controversial. OBJECTIVE: To clarify the prognosis of colorectal cancer after paraaortic lymph node metastasis resection. DESIGN: Multicenter retrospective study. SETTINGS Thirty-six institutions in Japan participated in this study. PATIENTS Patients with resected and pathologically proven paraaortic lymph node metastasis of CRC between 2010 and 2015. DATA SOURCES Database and medical records at each institution. MAIN OUTCOME MEASURES: Overall survival after paraaortic lymph node metastasis resection, recurrence-free survival, and recurrence patterns after R0 resection of paraaortic lymph node metastasis. RESULTS: A total of 133 patients were included in the primary analysis population in this study. The 5-year overall survival rate (95% confidence interval [CI]) was 41.0% (32.0, 49.8), and the median survival (95% CI) was 4.1 (3.4, 4.7) years. Independent prognostic factors for overall survival were the pathological T stage (pT4 vs. pT1- 3, adjusted hazard ratio [aHR] 1.91, p = 0.006), other organ metastasis (present vs. absent, aHR 1.98, p = 0.005), time to metastases (synchronous vs. metachronous, aHR 2.02, p = 0.02), and number of paraaortic lymph node metastasis (≥3 vs. <3, aHR 2.13, p = 0.001). The 5-year recurrence-free survival rate (95% CI) was 21.1% (13.5, 29.7), with a median (95% CI) of 1.2 (0.9, 1.4) years. The primary tumor location (left- vs. right-sided colon, aHR 4.77, p = 0.01; rectum vs. right-sided colon, aHR 5.27, p = 0.006), other organ metastasis (present vs. absent, aHR 1.90, p = 0.03), number of paraaortic lymph node metastasis (≥3 vs. <3, aHR 2.20, p = 0.001), and hospital volume (<10 vs. ≥10, aHR 2.18, p = 0.02) were identified as independent prognostic factors for recurrence-free survival. Paraaortic lymph node recurrence was the most common at 33.3%. LIMITATIONS: Selection bias cannot be ruled out because of the retrospective nature of the study. CONCLUSIONS: Less than three paraaortic lymph node metastasis was a favorable prognostic factor for both overall survival and recurrence-free survival. However, paraaortic lymph node metastases were considered to be a systemic disease and the significance of resection was limited. See Video Abstract.