The optimal number of lymph nodes examined in stage II colorectal cancer and its impact of on outcomes

Abstract

BackgroundLymph node status is the most important prognostic factor for colorectal cancer. The number of lymph nodes that should be histologically examined has been controversial. The aims of this study were to assess the impact of the number of lymph nodes examined on survival of patients with stage II colorectal cancer and to determine the optimal number of lymph nodes that should be examined.MethodsThe study included 664 patients who underwent resection for stage II colorectal cancer. The clinical and histopathologic data of the patients were prospectively collected and analyzed.ResultsThe median number of lymph nodes examined was 12 (range: 1 to 58). The 5-year disease free survival rate was significantly higher for patients with 12 or more lymph nodes examined compared to those with less than 12 lymph nodes examined. The significant difference in 5-year disease free survival persisted if the dividing number increased progressively from 12 to 23. However, the difference in survival was most significant (lowest p value and highest hazard ratio) for the number 21. The 5-year disease free survival of patients with 21 or more lymph nodes examined was 80% whereas that of patients with less than 21 lymph nodes examined was 60% (p = 0.001, hazard ratio 2.08). Multivariate analysis showed that 21 or more lymph nodes examined was a factor that independently influenced survival. The 5-year disease free survival also increased progressively with the number of lymph node examined up to the number 21. After the number 21, the survival rate did not increase further. It was likely that 21 was the optimal number, at and above which the chance of lymph node metastasis was minimal.ConclusionsThe number of lymph nodes examined in colorectal cancer specimen significantly influences survival. It is recommended that at least 21 lymph nodes should be examined for accurate diagnosis of stage II colorectal cancer.

Practice parameters for early colon cancer management: Italian Society of Colorectal Surgery (Società Italiana di Chirurgia Colo-Rettale; SICCR) guidelines

“…Hoenberger considered the lymph node harvest as a surrogate marker of surgical quality reporting a significant difference in survival between node-positive and node-negative patients with a cutoff point of 29 lymph nodes examined [123]. Similar results were reported by Choi with a significant difference in survival when a minimum of 21 nodes were examined; above this number there was no differences [124]. Although there is no consensus on what should be the cut-off point, it makes sense to conclude that the more lymph nodes are retrieved and examined the better will be the quality of care [125].…”

Review of Histopathological and Molecular Prognostic Features in Colorectal Cancer

“…In the UK, the Royal College of pathologists recommends examining a minimum of 12 nodes. Some published studies recommend higher number [25]. …”

“…In addition, if fewer than 12 lymph nodes were found after careful gross examination, it is suggested that additional techniques that aid in the macroscopic identification of lymph node, such as fat clearing, be considered. Likewise, examination of both halves of each node and preparation of more than one tissue level per paraffin block of nodes improves detection of metastatic disease [25]. …”

Clinical application of sentinel lymph node mapping in colon cancer:in vivovs.ex vivotechniques

“…Actually, other reports recommended that more lymph nodes should be examined to ensure proper staging [5,6]. However, it is time-consuming and impractical to obtain more lymph nodes.…”