Colorectal cancer and lymph nodes: The obsession with the number 12

Abstract

Lymphadenectomy of colorectal cancer is a decisive factor for the prognostic and therapeutic staging of the patient. For over 15 years, we have asked ourselves if the minimum number of 12 examined lymph nodes (LNs) was sufficient for the prevention of understaging. The debate is certainly still open if we consider that a limit of 12 LNs is still not the gold standard mainly because the research methodology of the first studies has been criticized. Moreover many authors report that to date both in the United States and Europe the number "12" target is uncommon, not adequate, or accessible only in highly specialised centres. It should however be noted that both the pressing nature of the debate and the dissemination of guidelines have been responsible for a trend that has allowed for a general increase in the number of LNs examined. There are different variables that can affect the retrieval of LNs. Some, like the surgeon, the surgery, and the pathology exam, are without question modifiable; however, other both patient and disease-related variables are non-modifiable and pose the question of whether the minimum number of examined LNs must be individually assigned. The lymph nodal ratio, the sentinel LNs and the study of the biological aspects of the tumor could find valid application in this field in the near future.

Preoperative Carcinoembryonic Antigen and Prognosis of Colorectal Cancer. An Independent Prognostic Factor Still Reliable

“…This number, though in the context of an issue still unresolved, 36 has been considered the minimum for a correct staging of the tumor. Currently data similar to ours has been reported in literature if it is true that in the US reports published between 2005 and 2010 revealed that lymphadenectomy was still considered inadequate in 48 to 63% of cases.…”

Comparison of Stage and Lymph Node Ratio in Young and Older Patients with Colorectal Cancer Operated in a Tertiary Hospital in Nepal

“…16 The number of positive nodes is dependent on the number of nodes dissected and the extent of resection of nodes as well as the location of the lesion.Lesions retrieved in the right side of colon are more commonly associated with a high frequency of positive nodes. 17,18 The dissection of 12 nodes is regarded as adequate for staging colorectal cancer, however, there is a controversy regarding whether this numberis inadequate lead to arisk of understaging.…”

“…It was similar to other studies where the retrieved nodes ranges from 10 to 26.8 nodes, which signifies the adequacy of nodal dissection in our study. 10,18 The cut off LNR has been reported to be 0.12 to 0.35. 10 In our series, the mean LNR was 0.31 in the younger patients where as in those above 40 years, it was 0.13 and the difference was statistically significant.…”

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

“…In recent population studies conducted in the USA and Europe, it has been reported that the ''magic'' number of 12 lymph nodes examined is rarely achieved in district or community hospitals which fail to hit the target in 33-60 % of the cases [115][116][117][118]. The national report card concluded that only the Comprehensive Cancer Centers were compliant with 92 % of patients with more than 12 lymph nodes retrieved, thus stressing the importance of a multidisciplinary team (MDT) approach and of developing of pooled experience [119].…”