LAUSR

We thank Dr Guo and colleagues for their interest in our research and their engaging insight on an interesting topic. Dr Guo highlighted how in a recent publication of his group a high number of lymphnodes harvested during pulmonary metastasectomy (PM) was a significant predictor of longer progression‐free survival (PFS). Even though we were not able to read the full article, we congratulate with the Authors for their research. We agree that the comparison between our investigations raises some interesting points of discussion. In accordance with what has been described by Dr Guo, our investigation showed a trend towards a lower recurrence of disease in the group of patients where lymphadenectomy was carried out (5 years‐PFS 80% vs. 63.2%), although the difference did not reach statistical significance (p = 0.073). However, there are some evident differences between our two studies: the number of resected lymphnodes, that turned out as a significant independent predictor of PFS in Dr Guo's study, is a parameter that unfortunately we could not analyze in our retrospective series, as reported in the manuscript. Nonetheless, in our population we compared patients who underwent lymphadenectomy with others that did not have any lymph node harvested, and the two groups had comparable sizes. We do not know the proportion of patients who underwent associated lymphadenectomy during PM in Dr Guo's series: if this is significantly dissimilar from ours, the differences in our respective conclusions might be justified by a difference in the populations of study. Nonetheless, as Dr Guo underlined, there is a notable difference in the proportion of patients whose PM was performed through a minimally invasive approach in our respective studies and this may have affected the results. In our series, we observed a slightly higher incidence of persistent air‐leak and arrhythmias in the lymphadenectomy group, but the result might be biased by the higher proportion of lobar resections in this group. We agree that lymphadenectomy itself does not necessarily expose patients to an increased risk of complications, and that it may help to stratify patients from a prognostic point of view and offer an indication for postoperative adjuvant treatments. However, in our opinion the presence of lymph nodes metastasis is a marker of a disease behavior that goes beyond the definition of “oligometastatic.” In this perspective, lymphadenectomy does not confer a real benefit in terms of prognostic outcomes. Therefore, we believe that patients should be accurately staged, and, in consideration of the well‐known detrimental effect of nodal metastases in patients with pulmonary metastasis, patients should be offered a surgical option once the presence of nodal involvement has been ruled out. Lastly, we acknowledge that the design of our study should pose some caution in interpreting the results, and an accurate prospective study assessing the impact of lymphadenectomy during PM would be of great value to define the real effect of this practice on oncological outcomes. We thank again Dr Guo and colleagues for their interesting considerations.