Lymph node count and prognosis in colorectal cancer: The influence of examination quality

Abstract

Colorectal cancer guidelines recommend adjuvant chemotherapy in stage II disease when less than 12 lymph nodes are assessed. The recommendation bases on previous studies showing an association of a low lymph node count and adverse outcome. Compared to current standards, however, the quality of lymph node examination in the studies was low. We, therefore, investigated the prognostic role of <12 lymph nodes in cancers diagnosed adherent to current quality measures. Stage I-IV colorectal cancers from 1,899 patients enrolled into a population-based cohort study were investigated for the prognostic impact of a lymph node count <12. The stage specific share of patients diagnosed with 12 nodes (stage I-IV: 62, 85, 85, 78%, respectively) was used to compare lymph node examination quality to other studies. We found no impact of a lymph node count <12 on overall, cancer-specific or recurrence-free survival for any tumour stage. Compared to studies reporting an adverse prognostic impact of a low lymph node count in stages II and III the stage-specific shares of patients with 12 nodes were markedly higher in this study (85% vs. 24-58% in previous analyses) and this correlated with increased rates of stage III compared to stage II cancers. In conclusion our data indicate, that the previously reported effect of a low lymph node count on the patients' outcomes is eliminated by improved lymph node examination quality and thus question the general applicability of a 12 lymph node cut off for adjuvant chemotherapy decision making in stage II disease.

Role of lymph node yield and lymph node ratio in predicting outcomes in non-metastatic colorectal cancer

“…LNY is an important prognostic factor in patients with stage II–III colorectal cancer, but evidence for stage I colorectal cancer is unclear,,. Although there are studies reporting differences in survival between low and high LNY in patients with Dukes' A/stage I colorectal cancer,, some indicate that LNY alone has no effect on survival outcome. The present study highlights that a substantial number of patients with stage I and II colorectal cancer have a low LNY.…”

A nomogram improves AJCC stages for colorectal cancers by introducing CEA, modified lymph node ratio and negative lymph node count

“…This is in accord with a recent population-based study, in which the 12-node benchmark proved to be an independent predictor of CRC in patients with stage I-III disease ( n  = 13,941, HR = 0.67) but not in patients with stage III-IV disease ( n  = 6810, P  = 0.136)24. Another possible reason is that the influence of the LNC on patient survival is more easily diminished by improvements in the quality of external pathology with increasing awareness of the 12-node minimum requirement26. In contrast, the NLNC may be more intrinsically related to enhanced regional lymphocytic reactions that result in an increased NLNC and prolonged survival27.…”

Log odds of positive lymph nodes as a prognostic indicator in stage IV colorectal cancer patients undergoing curative resection

“…One explanation for higher frequency of more than 12 LNs retrieved in the LNR1 and LNR2 groups compared to LNR0 group is that insufficient lymph node dissection or pathological examination might be performed in the patients with fewer retrieval of LNs, and positive LNs were not dissected or misdiagnosed as negative. Another explanation is that higher immunological reaction may occur in the patients with more aggressive disease, as previous study reported that the frequency of total lymph nodes less than 12 varied by tumor Stage (Stage I: 38%, Stage II and III: 15%) .…”