Can mathematics replace anatomy to establish recommendations in lung cancer surgery?

The greater the number of lymph node (LN) sampled (NLNsS) during lung cancer surgery, the lower the risk of underestimating the pN-status and the better the outcome of the pN0-patients due to stage-migration. Thus, regarding LN sampling “to be or not to be”, number is the question. Recent studies advocate removing 10 LNs. The most suitable NLNsS is unfortunately impossible to establish by mathematics. A too high NLNsS variability exists, based on anatomy, surgery and pathology. The methodology may vary according to Inter-institutional differences in the surgical approach regarding LN inspection and number sampling. The NLNsS increases with the type of resection: sublobar, lobectomy or pneumonectomy. Concerning pathology, one LN may be divided into several pieces, leading to number overestimation. The pathological examination is limited by the number of slices analyzed by LN. The examined LNs can arbitrarily depend on the probability of detecting nodal metastasis. In fact, the only way to ensure the best NLNsS and the best pN-staging is to remove all LNs from the ipsilateral mediastinal and hilar LN-stations as they are discovered by thoroughly dissecting their anatomical locations. In doing so, a deliberate lack of harvest of LNs is unlikely, number turns out not to be the question anymore and a low NLNsS no longer means incomplete surgery. This prevents from judging as incomplete a complete LN dissection in a patient with a small NLNsS and from considering as complete a true incomplete one in a patient with a great NLNsS. Precise information describing the course of the operation and furnished in the surgeon's reports is also advisable to further improve the quality of LN-dissection, which ultimately might be beneficial in the long-term to patients. However, that procedure is of limited interest in pN-staging if LNs are not thoroughly examined and also described by the pathologist.