The prognostic value of the number of lymph nodes removed in patients with node-negative colorectal cancer

Number of lymph nodes retrieved in patients with locally advanced rectal cancer after total neoadjuvant therapy: post-hoc analysis from the STELLAR trial

BACKGROUND

The current gold standard for extraperitoneal locally advanced rectal cancer is total neoadjuvant therapy (TNT) followed by total mesorectal excision. This research explored the number of lymph nodes in patients with locally advanced rectal cancer after TNT and its correlation with survival.

MATERIALS AND METHODS

This is a post-hoc analysis based on the STELLAR trial, including patients with locally advanced rectal cancer from 16 tertiary centres who were randomized for short-term radiotherapy followed by chemotherapy (TNT group) or long-term concurrent chemotherapy group followed by total mesorectal excision between 2015 and 2018. This lymph node-related analysis is based on the TNT group. Subgroups were differentiated based on the lymph node harvest (below the median number: limited lymphadenectomy group, and greater than/equal to the median number: extended lymphadenectomy group). The primary outcomes were overall survival and disease-free survival (DFS). Correlations with clinical/pathological variables, lymphadenectomy categories and use of adjuvant chemotherapy were explored.

RESULTS

Among the 451 patients enrolled in the STELLAR trial, 227 patients (50.3%) were assigned to the TNT group, including 29.5% females. The median number of lymph nodes retrieved in the TNT group was 11.0. Patients in the limited lymphadenectomy subgroup exhibited worse overall survival than those with extended lymphadenectomy (HR 2.95 (95% c.i. 1.47 to 5.92), P = 0.001). The overall survival was similar in the ypN0-limited and ypN1-extended subgroups (HR 0.38 (95% c.i. 0.11 to 1.30), P = 0.109). Adjuvant chemotherapy was associated with better overall survival and DFS than no adjuvant chemotherapy overall (P < 0.001) and in the limited lymphadenectomy subgroup (P < 0.001). However, there was no significant difference in overall survival or DFS with or without adjuvant chemotherapy in the extended lymphadenectomy subgroup (P = 0.887 and P = 0.192, respectively).

CONCLUSION

In the STELLAR trial, the median number of lymph nodes harvested was 11. In patients with limited lymphadenectomy, the use of adjuvant therapy after TNT was beneficial and correlated with better prognosis compared with patients who did not receive adjuvant chemotherapy.

Finding the minimum number of retrieved lymph nodes in node-negative colorectal cancer using Real-world Data and the SEER database

BACKGROUND

Current clinical guidelines recommend the removal of at least 12 lymph nodes (LNs) in resectable colorectal cancer (CRC). With advancements in lymphadenectomy technologies, the number of retrieved lymph nodes (rLNs) has markedly increased. This study aimed to investigate the lowest number of rLNs in node-negative patients.

MATERIALS AND METHODS

A total of 1103 N0 and 208 N1a stage patients were enrolled in our cohort, while 8503 N0 and 1276 N1a patients from the Surveillance, Epidemiology, and End Results CRC database were included. Propensity score matching and multivariate Cox regression analyses were performed to mitigate the influence of selection bias and control for potential confounding variables.

RESULTS

The median number of rLNs in N0 patients increased from 13.5 (interquartile range [IQR]: 9-18) in 2013 to 17 (IQR: 15-20) in 2019. The restrictive cubic spline illustrated a nonlinear relationship between rLNs and prognosis (nonlinearity, P =0.009), with a threshold ( N =16) influencing clinical outcomes. Patients at either N0 or N1a stage with sufficient rLNs (≥16) demonstrated superior prognoses to those with a limited rLNs (<16). After adjusting for clinical confounders, similar prognoses were observed in N0 limited and N1a adequate populations. Furthermore, Kaplan-Meier curves revealed that N0 limited patients who received chemotherapy exhibited better outcomes than those who did not.

CONCLUSIONS

Among patients with node-negative CRC, it is crucial to remove 16 or more LNs effectively. Fewer than 16 rLNs should be regarded as an independent risk factor, implying the need for adjuvant chemotherapy.

Developing prognostic nomograms to predict overall survival and cancer-specific survival in synchronous multiple primary colorectal cancer based on the SEER database

BACKGROUND

Synchronous multiple primary colorectal cancer (SMPCC) is a rare subtype of CRC, characterized by the presence of two or more primary CRC lesions simultaneously or within 6 months from the detection of the first lesion. We aim to develop a novel nomogram to predict OS and CSS for SMPCC patients using data from the SEER database.

METHODS

The clinical variables and survival data of SMPCC patients between 2004 and 2018 were retrieved from the Surveillance, Epidemiology, and End Results (SEER) database. Appropriate inclusion and exclusion criteria were established to screen the enrolled patients. Univariate and multivariate Cox regression analyses were used to identify the independent risk factors for OS and CSS. The performance of the nomogram was evaluated using the concordance index (C-index), calibration curves, and the area under the curve (AUC) of a receiver operating characteristics curve (ROC). A decision curve analysis (DCA) was generated to compare the net benefits of the nomogram with those of the TNM staging system.

RESULTS

A total of 6772 SMPCC patients were enrolled in the study and randomly assigned to the training (n = 4670) and validation (n = 2002) cohorts. Multivariate Cox analysis confirmed that race, marital status, age, histology, tumor position, T stage, N stage, M stage, chemotherapy, and the number of dissected LNs were independent prognostic factors.The C-index values for OS and CSS prediction were 0.716 (95% CI 0.705-0.727) and 0.718 (95% CI 0.702-0.734) in the training cohort, and 0.760 (95% CI 0.747-0.773) and 0.749 (95% CI 0.728-0.769) in the validation cohort. The ROC and calibration curves indicated that the model had good stability and reliability. Decision curve analysis revealed that the nomograms provided a more significant clinical net benefit than the TNM staging system.

CONCLUSION

We developed a novel nomogram for clinicians to predict OS and CSS, which could be used to optimize the treatment in SMPCC patients.

Survival Contradiction in Stage II, IIIA, And IIIB Colon Cancer: A Surveillance, Epidemiology, and End Result-Based Analysis

There exists an inconsistency between stage and survival in the current American Joint Committee on Cancer (AJCC) staging system for colon cancer. In this study, we compared the clinicopathological characteristics and prognosis of colon cancer patients with stage II, IIIA, and IIIB disease based on the surveillance, epidemiology, and end results (SEER) database. Kaplan-Meier analysis was used to generate overall survival (OS) and cancer-specific survival (CSS) curves. The Cox regression was employed to identify risk factors. The competing risk model was completed by the cumulative incidence function and Gray's test. In the final population of 31,361 colon cancer patients, Kaplan-Meier curve analysis showed that stage IIIA had the highest OS and CSS, followed by stage IIA and IIIB, and IIB and IIC showed the worst OS and CSS. In the Cox model, the stage was proven to be an independent prognostic factor. In the competing risk model, stage IIIA colon cancer patients had the lowest 5-year cancer-specific death rate in stages II, IIIA, and IIIB. In conclusion, the prognosis of colon cancer patients in stage IIA was worse than that of patients in stage IIIA, while the survival rate of stage IIB and IIC was lower than that of stage IIIB.

A nomogram for predicting 10-year cancer specific survival in patients with pathological T3N0M0 rectal cancer

Background

The pathological T3N0M0 (pT3N0M0) rectal cancer is the earliest stage and has the best prognosis in the locally advanced rectal cancer, but the optimal treatment remains controversial. A reliable prognostic model is needed to discriminate the high-risk patients from the low-risk patients, and optimize adjuvant chemotherapy (ACT) treatment decisions by predicting the likelihood of ACT benefit for the target population.

Patients and methods

We gathered and analyzed 276 patients in Sun Yat-sen University Cancer Center from March 2005 to December 2011. All patients underwent total mesorectal excision (TME), without preoperative therapy, and were pathologically proven pT3N0M0 rectal cancer with negative circumferential resection margin (CRM). LASSO regression model was used for variable selection and risk factor prediction. Multivariable cox regression was used to develop the predicting model. Optimum cut-off values were determined using X-Tile plot analysis. The 10-fold cross-validation was adopted to validate the model. The performance of the nomogram was evaluated with its calibration, discrimination and clinical usefulness.

Results

A total of 188 patients (68.1%) had ACT and no patients had adjuvant radiotherapy. Age, monocyte percentage, carbohydrate antigen 19–9, lymph node dissection numbers and perineural invasion (PNI) were identified as significantly associated variables that could be combined for an accurate prediction risk of Cancer Specific Survival (CSS) for pT3N0M0 patients. The model adjusted for CSS showed good discrimination with a C-index of 0.723 (95% CI: 0.652–0.794). The calibration curves showed that the nomogram adjusted for CSS was able to predict 3-, 5-, and 10-year CSS accurately. The corresponding predicted probability was used to stratify high and low-risk patients (10-year CSS: 69.1% vs. 90.8%, HR = 3.815, 95%CI: 2.102–6.924, P < 0.0001). ACT improved overall survival (OS) in the low-risk patients (10-year OS: 91.9% vs. 83.3%, HR = 0.338, 95% CI: 0.135–0.848, P < 0.0001), while it did not exhibit a significant benefit in the high-risk patients.

Conclusion

The present study showed that age, monocyte percentage, carbohydrate antigen 19–9, lymph node dissection numbers and PNI were independent prognostic factors for pT3N0M0 rectal cancer patients. A nomogram based on these prognostic factors effectively predicts CSS in patients, which can be conveniently used in clinical practice. ACT may improve overall survival in the low-risk patients. But the benefit of ACT was not seen in the high-risk patients.

Definition of an extended minimum level of lymphadenectomy in non-pancreatic periampullary cancer resections

BACKGROUND

The number of lymph nodes to be resected in surgery for non-pancreatic periampullary cancer remains unclear.

METHODS

The Surveillance, Epidemiology, and End Results (SEER) database was used to gather information from a large retrospective cohort. To define a novel, reasonable cut-off associated with survival, we stratified patients into subgroups depending on the number of resected lymph nodes.

RESULTS

1481 nodal-negative patients resected for periampullary cancer (excluding pancreatic ductal adenocarcinoma) were included. The median number of resected lymph nodes was ten. Median overall survival in the subgroup with less than 10 removed lymph nodes was 40 months, while median survival for patients with ≥10 lymph nodes was 97 months (p < 0.001). A significant survival benefit was seen if ≥ 16 lymph nodes were harvested (median survival, 117 months), while no further benefit was observed if more than 21 nodes were removed (median survival, >120 months).

CONCLUSION

Sixteen or more resected lymph nodes are associated with improved survival in node-negative periampullary carcinoma. We propose to aim at harvesting and analyzing at least 16 lymph nodes.

Survival Contradiction Between Stage IIA and Stage IIIA Rectal Cancer: A Retrospective Study

Background: When compared with patients harboring stage IIB and stage IIC disease, those with stage IIIA colorectal cancer have a better prognosis. We aimed to compare the cause-specific survival (CSS) of the patients with stage IIA rectal cancer with that of the patients with stage IIIA rectal cancer.

Methods: Data analyzed about patients with stage IIA and stage IIIA rectal cancer was from the US Surveillance, Epidemiology, and End Results (SEER) database. We then validated the results using data derived from Fudan University Shanghai Cancer Center (FUSCC).

Results: A total of 16,788 patients (13,551 staged IIA and 3,237 staged IIIA) were identified in SEER database. A multivariate analysis manifested that patients with stage IIIA disease were more likely to have a better CSS (HR 0.894, 95% CI 0.816-0.979, p=0.016) compared with patients with stage IIA rectal cancer. In the subgroup of patients whose number of lymph nodes harvested (LNH) <12, multivariate analysis signified that patients with stage IIIA disease were more prone to have favorable CSS (HR 0.805, 95% CI 0.719-0.901, p<0.001) compared with patients with stage IIA rectal cancer. In LNH≥12 subgroup, the Kaplan-Meier analysis revealed no significant difference between patients experiencing stage IIA and IIIA rectal cancer (p=0.618). Validation of data from FUSCC proved that patients with stage IIIA rectal cancer were more inclined to have better CSS (HR 0.407, 95% CI 0.187-0.885, p=0.019) in comparison to those with stage IIA rectal cancer. Specifically, in LNH<12 subgroup, the survival outcomes of stage IIIA patients were significantly better than that of the stage IIA patients (p=0.019), while there was no statistical significance between these two stages in the subgroup of patients with LNH≥12 (p=0.180).

Conclusions: Patients with stage IIA rectal cancer have poorer CSS than patients with stage IIIA rectal cancer, particularly when inadequate lymph nodes are harvested.

Stage migration vs immunology: The lymph node count story in colon cancer

Lymph node staging is of crucial importance for the therapy stratification and prognosis estimation in colon cancer. Beside the detection of metastases, the number of harvested lymph nodes itself has prognostic relevance in stage II/III cancers. A stage migration effect caused by missed lymph node metastases has been postulated as most likely explanation for that. In order to avoid false negative node staging reporting of at least 12 lymph nodes is recommended. However, this threshold is met only in a minority of cases in daily practice. Due to quality initiatives the situation has improved in the past. This, however, had no influence on staging in several studies. While the numbers of evaluated lymph nodes increased continuously during the last decades the rate of node positive cases remained relatively constant. This fact together with other indications raised doubts that understaging is indeed the correct explanation for the prognostic impact of lymph node harvest. Several authors assume that immune response could play a major role in this context influencing both the lymph node detectability and the tumor’s behavior. Further studies addressing this issue are need. Based on the findings the recommendations concerning minimal lymph node numbers and adjuvant chemotherapy should be reconsidered.