Background: It is necessary to identify valuable predictors of primary lymph node metastasis and prognosis for patients with synchronous colorectal cancer liver metastases (CRLM) with simultaneous resection of colorectal cancer (CRC) and liver metastases. This study constructed nomograms especially incorporating preoperative testing markers to predict primary lymph node metastases and prognosis in CRLM patients.
Methods: By the highest Youden index (sensitivity + 1-specificity), the optimal cut-off values of testing markers for postoperative major complications and lymph node metastasis were identified. Multivariate regression analysis was used to reveal independent predictors for primary lymph node metastasis, postoperative major complications and progression-free survival (PFS). Nomograms based on independent predictors were constructed, and the discrimination and calibration were evaluated.
Results: A nomogram predicting primary lymph node metastasis was based on four risky independent predictors: American Society of Anesthesiologists (ASA) score 3-4, preoperative albumin (ALB) <41.15 g/L, poor differentiation and multiple liver metastases. The performance of the model was acceptable in predicting lymph node metastasis, with an area under the receiver operating characteristic curve (AUROC) of 0.655 (95% CI: 0.591-0.739). Calibration curves and the Hosmer-Lemeshow test revealed desirable model calibration (chi-square: 13.26, P=0.815). In the multivariate analysis, preoperative lactate dehydrogenase (LDH) ≥202.5 U/L [odds ratio (OR) =2.084, 95% confidence interval (CI): 1.039-4.181, P=0.039] and operation time ≥350.5 min (OR =2.848, 95% CI: 1.418-5.723, P=0.003) were independently associated with the presence of postoperative major complications. A nomogram predicting PFS was constructed based on poor differentiation, positive lymph node metastasis, bilobar liver distribution and R0 resection with good discrimination (C-index: 0.656±0.021) and calibration.
Conclusions: This study established predictive nomograms specifically incorporating preoperative ALB and LDH levels for the prediction of primary lymph node metastasis and prognosis in synchronous CRLM patients with simultaneous resection, which have favourable discrimination and calibration to make individualized predictions.
Keywords: Colorectal liver metastases; lymph node metastasis; nomogram; postoperative complications; progression-free survival (PFS).