[Establishment of a clinical risk scoring model for patients undergoing curative resection of pulmonary metastases from colorectal cancer based on primary tumor lymph node indices].

Objective: To analyze the clinicopathological factors affecting the prognosis of patients after curative resection of lung metastases (LMs) from colorectal cancer (CRC) and to construct a clinical risk scoring (CRS) model. Methods: This study retrospectively collected clinicopathological data and follow-up information on 132 patients who underwent radical resection of LMs from CRC at the Cancer Hospital of the Chinese Academy of Medical Sciences between January 2010 and December 2020. We analyzed the clinicopathological factors influencing patient prognosis using univariate and multivariate Cox proportional hazards regression models, and we developed a risk stratification model for prognostic prediction. Results: The median follow-up duration for the cohort of 132 patients was 54.2 months. During this period, 61 patients (46.2%) experienced recurrence or distant metastasis, resulting in a 5-year DFS rate of 54.1%. Additionally, 33 patients (25.0%) died, corresponding to a 5-year overall survival (OS) rate of 76.7%. Univariate Cox proportional hazards regression model analysis indicated that ten clinicopathological factors were significantly associated with OS (all P＜0.05). These factors include the total number of lymph nodes (LNs) dissected from the primary tumor (PT) <16, the number of negative LNs from the PT <13, pN(+) of the PT, logarithmic odds of positive lymph nodes (LODDS) of the PT ≥-1.1, lymph nodes ratio (LNR) of the PT ≥0.02, preoperative carcinoembryonic antigen (CEA) level before LMs resection ≥10 ng/ml, the presence of hilar/mediastinal LN metastasis, the number of LMs ≥2, the maximum diameter of LMs ≥2.5 cm, and the necessity for hilar/mediastinal lymphadenectomy. Multivariate Cox proportional hazards regression analysis identified the number of negative LNs <13 (HR=3.01, 95% CI: 1.28-7.03, P=0.011), pN(+) of the PT (HR=5.04, 95% CI: 1.51-16.84, P=0.009), preoperative CEA level before LMs resection ≥10 ng/ml (HR=5.39, 95% CI: 1.80-16.19, P=0.003), the number of LMs ≥2 (HR=2.47, 95% CI: 1.09-5.60, P=0.030), and the necessity for hilar/mediastinal lymphadenectomy (HR=2.74, 95% CI: 1.15-6.52, P=0.023) as independent prognostic risk factors. Patients were categorized based on independent risk factors, revealing statistically significant differences in OS across the groups with CRS scores of ≤2, 3～4, and ≥5 (P＜0.001). Conclusions: Independent risk factors associated with LMs from CRC patients include the number of negative LNs <13, pN(+) of the PT, preoperative CEA level before LMs resection ≥10 ng/ml, the number of LMs ≥2, and the necessity for hilar/mediastinal lymphadenectomy. Patients scoring 3 or higher on the CRS model may warrant cautious assessment for the appropriateness of direct surgical treatment.