A statistical tool for risk assessment as a function of the number of lymph nodes retrieved from rectal cancer patients

The Effect of Lymph Node Harvest on Prognosis in Locally Advanced Middle-Low Rectal Cancer After Neoadjuvant Chemoradiotherapy

OBJECTIVE

The purpose of this study was to investigate the relationship between lymph node harvest and the prognosis in locally advanced rectal cancer (LARC) patients after neoadjuvant chemoradiotherapy (nCRT).

METHODS

Patients who were diagnosed with clinical LARC and treated with nCRT and radical surgery between June 2008 and July 2017 were included in this study. The relationship between lymph node retrieval and prognosis was analyzed. Other lymph node-related indicators were explored.

RESULTS

A total of 837 patients with a median follow-up of 61 (7-139) months were included in the study. The five-year DFS and OS rates of all patients were 74.9% and 82.3%, respectively. Multivariate survival analysis suggested that dissection of ≥ 12 lymph nodes did not improve OS or DFS. 7 was selected as the best cutoff value for the total number of lymph nodes retrieved by Cox multivariate analysis (χ2 = 10.072, HR: 0.503, P=0.002). Dissection of ≥ 5 positive lymph nodes (PLNs) was an independent prognostic factor for poorer DFS (HR: 2.104, P=0.004) and OS (HR: 3.471, p<0.001). A positive lymph node ratio (LNR) of more than 0.29 was also an independent prognostic factor for poorer DFS (HR: 1.951, P=0.002) and OS (HR: 2.434, p<0.001).

CONCLUSION

The recommends that at least 7 harvested lymph nodes may be more appropriate for LARC patients with nCRT. PLN and LNR may be prognostic factors for LARC patients with ypN+ after nCRT.

The prognostic impact of neoadjuvant chemoradiotherapy on lymph node sampling in patients with locally advanced rectal cancer

According to the American Joint Committee on Cancer, at least 12 lymph nodes are required to accurately stage locally advanced rectal cancer (LARC). Neoadjuvant chemoradiation therapy (NACRT) reduces the number of lymph nodes retrieved during surgery. In this study, we evaluated the effect of NACRT on lymph node retrieval and prognosis in patients with LARC. We performed an observational study of 142 patients with LARC. Although our analysis was retrospective, data were collected prospectively. Half the patients were treated with NACRT and total mesorectal excision (TME) and the other half underwent TME only. The number of lymph nodes retrieved and the number of metastatic lymph nodes were significantly reduced in the NACRT group (P > 0.001). In the univariate and multivariate analyses, only NACRT and patient age were significantly associated with reduced lymph node retrieval. The number of metastatic lymph nodes and the lymph node ratio (LNR) both had a significant effect on prognosis when the patient population was examined as a whole (P = 0.003 and P = 0.001, respectively). However, the LNR was the only significant, independent prognostic factor in both treatment groups (P = 0.007 for the NACRT group; P = 0.04 for the no-NACRT group). NACRT improves patient prognosis only when the number of metastatic lymph nodes is reduced. The number of metastatic lymph nodes and the LNR are important prognostic factors. Lymph node retrieval remains an indispensable tool for staging and prognostic assessment of patients with rectal carcinoma treated with NACRT.

Development and validation of a nomogram to predict survival after curative resection of nonmetastatic colorectal cancer

Background

We aimed to develop a clinical applicable nomogram to predict overall survival (OS) for patients with curatively resected nonmetastatic colorectal cancer.

Methods

Records from a retrospective cohort of 846 patients with complete information were used to construct the nomogram. The nomogram was validated in a prospective cohort of 379 patients. The performance of the nomogram was evaluated with concordance index (c‐index), time‐dependent receiver operating characteristic (ROC) curves, calibration plots, and decision curve analyses for discrimination, accuracy, calibration ability, and clinical net benefits respectively, and further compared with AJCC 8th TNM staging and the MSKCC nomogram. Risk stratification based on nomogram scores was performed with recursive partitioning analysis.

Results

The nomogram incorporated age, Glasgow prognostic score, pretreatment carcinoembryonic antigen levels, T staging, N staging, number of harvested lymph nodes, and histological grade. Compared with the 8th AJCC staging and MSKCC model, the nomogram had a statistically higher c‐index (0.77, 95% CI: 0.73‐0.80), bigger areas under the time‐dependent ROC curves (AUC at 3 years: 79; at 5 years: 79), and improved clinical net benefits. Calibration plots revealed no deviations from reference lines. All results were reproducible in the validation cohort. Nomogram‐based risk stratification successfully discriminated patients within each AJCC stage (all log‐rank P < .05).

Conclusion

We established an accurate, reliable, and easy‐to‐use nomogram to predict OS after curative resection for nonmetastatic colorectal cancer (CRC). The nomogram outperformed the 8th AJCC staging and the MSKCC model and could aid in personalized treatment and follow‐up strategy for CRC patients.