Editorial Comment to Development and external validation of lymph node density cut‐off points in prospective series of radical cystectomy and pelvic lymph node dissection

Abstract

Simone et al. aimed to develop relevant prognostic cut-off values for lymph node density (LN-d).1 The concept is well known and the present paper gives an excellent review of the literature regarding this. The present paper is also, in my opinion, one of the best papers regarding this subject, as it also includes an external validation of the findings. However, I still have difficulties understanding the clinical relevance of LN-d. In the final conclusions, the authors suggest using LN-d to select patients for adjuvant therapy – but to my knowledge, the evidence supporting a benefit of adjuvant therapy does not exist.2 Furthermore, in the present study, it is shown how adjuvant chemotherapy does not reduce cancer specific survival – so how should that change in this minority of patients who will eventually die of their disease anyway, despite chemotherapy (immediate or referred)? The present study also shows one of the downsides of LN-d. That is that the lymph node count is dependent on the pathologist rather than the surgeon. This is consistent with the finding of Parkash et al.3 This is a true disadvantage of LN-d, whereas the number of metastatic lymph nodes is more stable from an interobserver point of view. Furthermore, at Aarhus University Hospital, Aarhus, Denmark, we have found the number of lymph nodes to be more variable between patients undergoing lymph node dissection according to the same extended template than the amount of lymphatic tissue removed.4 In contrast, the present study provides excellent indirect proof that an extended template is better than a standard template lymph node dissection; and this might be of more importance than the number of lymph nodes removed and, thus, LN-d. The present study shows that the hazard ratio is twice as high going from an extended to a standard template, whereas the hazard ratio is only increased by 50% going from one LN-d group to another. During surgery, I personally have difficulty counting the number of lymph node metastases and then dissecting more than eight times as many negative lymph nodes as suggested. Furthermore, if the patient has more than 10 metastases, will he benefit from me dissecting all lymph nodes up to the axillae? I do not necessarily think so. However, during surgery I will be perfectly able to carry out an extended lymph node dissection in all patients. The most important part of the surgery might not be removing many lymph nodes, but to remove the right ones. None declared.