Lymph node dissection does not affect the survival of patients with tumor node metastasis stages I and II colorectal cancer

Lymph node yield does not affect the cancer-specific survival of patients with T1 colorectal cancer: a population-based retrospective study of the U.S. database and a Chinese registry

PURPOSE

This study aimed to investigate the association between lymph node yield (LNY) and cancer-specific survival (CSS) in patients with T1 colorectal cancer (CRC) via data from two large cohorts.

METHODS

We analyzed data from 4186 patients in the SEER cohort (2010-2015) and 533 patients from CHCAMS (2014-2019). Patients were categorized into two groups based on whether their LNY was above or below the guideline-recommended threshold of 12 nodes. Propensity score matching was used to adjust for confounding factors, and survival analysis was conducted using Kaplan-Meier and Cox proportional hazards models.

RESULTS

No significant difference in CSS was found between patients with LNY ≥ 12 and those with LNY < 12 in either the SEER or CHCAMS cohorts (log-rank P > 0.05 for both). After multivariate adjustment, LNY was not independently associated with CSS. Factors such as age, tumor location, elevated preoperative CEA levels, and adjuvant chemotherapy were significant prognostic factors in the SEER cohort. In the CHCAMS cohort, lymph node metastasis (LNM) emerged as the sole independent predictor of CSS.

CONCLUSION

Our findings suggest that LNY is not significantly associated with CSS in patients with T1 CRC, challenging the necessity of adhering to the 12-node benchmark for early-stage disease. Instead, factors such as tumor biology, LNM, and patient demographics may be more relevant in determining survival outcomes. Further prospective studies are needed to validate these findings and refine guidelines for lymph node assessment in early-stage CRC.

Does lymph node dissection improve the prognosis of patients with colorectal cancer?

The number of lymph nodes (LNs) dissected during surgery has become an interesting topic. Simple intuition always leads us to believe that dissecting more LNs will result in more accurate pathological staging and assurance of surgical quality. However, when the number of LNs dissected reaches a certain threshold, the patient's prognosis does not continue to improve as the number of dissected nodes increases. Instead, an increase in the number of dissected LNs may be accompanied by a higher incidence of complications. Currently, there are only less than 40% of colorectal cancer patients undergoing adequate LN evaluation. Therefore, obtaining a sufficient number of LNs in clinical practice is extremely challenging. How to further address the insufficiency of LN dissection due to various reasons, which results in concerns of surgeons about patient prognosis, is currently a critical focus.

Colorectal cancer lymph node dissection and disease survival

The debate regarding the two possible roles of lymphadenectomy in surgical oncology, prognostic or therapeutic, is still ongoing. Furthermore, the use of lymphadenectomy as a proxy for the quality of the surgical procedure is another feature of discussion. Nevertheless, this reckoning depends on patient conditions, aggressiveness of the tumor, the surgeon, and the pathologist, and then it is not an absolute surrogate for the surgical quality. The international guidelines recommend a minimum of 12 lymph nodes harvested for pathological examination in colorectal cancer (CRC) surgery. There is a growing literature on reporting better survival when the lymph node yield is high, even when these nodes are negative for malignancy. On the other hand, there are studies reporting no survival benefit with high lymph node yield in stage I-II of CRC. Herein we review the roles of the lymphadenectomy in CRC, and discuss the results of studies on lymph node harvesting.