Should mediastinal lymphadenectomy be performed during lung metastasectomy of renal cell carcinoma?

A best evidence topic was constructed according to a structured protocol. The question addressed was whether radical mediastinal lymphadenectomy should be performed during lung metastasectomy of renal cell carcinoma (RCC). Of the 13 papers found through a report search, seven represent the best evidence to answer this clinical question. The authors, journal, date, country of publication, study type, group studied, relevant outcomes and results of these papers are given. We conclude that on the whole, the seven-retrieved studies support the realization of systematic radical mediastinal lymphadenectomy. The published literature showed a prevalence of lymph node involvement (LNI) that approaches 30%. The majority of the studies conclude that LNI is a significant, independent prognostic of survival. Indeed, some authors did not report any 5-year survival in the case of LNI. On the contrary, however, a 5-year survival of ~50% was reported when no LNI was present. To date, the published data do not allow conclusions to be drawn regarding the prognosis of hilar vs mediastinal LNI: only one paper focused on the difference between hilar and mediastinal location and showed no difference. In addition, only one study has compared the survival of patients with or without lymphadenectomy, showing greater survival when mediastinal lymphadenectomy was performed. Despite the poor prognosis of patients with LNI, surgery seems to be the best treatment for potentially curative RCC with metastases. It is known that RCC metastases do not respond well to chemotherapy and radiotherapy. Indeed, reported 5-year survival rate ranged between 3 and 11% for non-operated patients. Consequently, resection must be as complete as possible and include a systematic total mediastinal lymphadenectomy, which will probably yield better loco-regional control and evaluation of prognostic factor. However, the published evidence remains quite limited and mainly based on retrospective studies on highly selected patients, with a low level of evidence. Indeed, most patients referred to surgery are younger, fitter, and have fewer metastases. Consequently, the survival gain could be biased, related more to the resectability and the good performance status rather to the resection itself. Consequently, although these preliminary results are interesting, they must be interpreted with caution.