Staging in colorectal cancer:problems for pathologists

We have read with interest the paper by Quirke and Morris, published in Histopathology, about the guidelines for the reporting of surgically resected specimens of colorectal carcinoma. We would like to comment on some controversial issues concerning the number of lymph nodes to be recovered and the utilization of the fifth rather than the sixth edition of TNM. The authors state that 15–18 lymph nodes are usually recovered in the best centres and this number is advisable for all pathologists. However, there is no general consensus given that other authors, reporting colorectal cancer guidelines, have recently proposed a mean number of 12–15 lymph nodes. We have recently shown that in pT3 rectal cancer 15–18 lymph nodes are insufficient for correct staging and that, if the mean number of lymph nodes recovered increases from 17.8 to 26.8 after a second sampling of the same surgically resected specimens, metastases are detected in 18.7% of patients that had been originally understaged. Our results are in line with those previously obtained by other authors, showing that most lymph node metastases (about 80–90% of cases) of colorectal cancer are detected if about 26–30 lymph nodes are recovered.