Lymph node involvement in T1 non-small-cell lung cancer: do not miss radical lymphadenectomy Free

I read with interest the article by Casiraghi et al. [1] and I would like to share a few comments. This article is of great interest as the proportion of small non-small-cell lung cancer (NSCLC) is increasing while we improve early diagnosis, but some points are disconcerting.

First, the authors precisely state in the introduction the impact of tumor size exposed in the latest TNM classification, but did not expose the impact of N staging. Although the N description has not changed within the 2007 International Association for the Study of Lung Cancer (IASCL) lung staging system, some findings regarding N status are significant [2]. Indeed, three prognosis groups are merging: good prognosis (single zone N1), intermediate prognosis (multiple zones N1 and single zone N2), and poor prognosis (multiple zones N2). This highlights the need for an extended lymphadenectomy for a rigorous pTNM classification, irrespective of T size, thus confounding the carcinologic and the staging role of this procedure.

Second, concerning positron emission tomography/computed tomography (PET/CT), it is known that its sensitivity is poor for structures under 1-cm length, (tumor or lymph node). A recent retrospective study points out sensitivity up to 32.4% for infra-centimeter nodes [3]. However, the authors mention ‘PET/CT is a reliable tool versus CT in evaluating both solitary nodules and lymph node involvement.’ It seems for us mandatory to draw attention that those two procedures are not to oppose. CT is the anatomical tool for thorax imaging and newest machines (256-detector row) are offering excellent spatial resolution. The PET/CT is not an anatomic examination but a functional tool offering information about metabolic activity of the structure identified with fusion images of a low-resolution CT (16-detector row).

Third, in the era of molecular biology, we are finding evidence of disease aggressiveness regarding microvascular invasion [4] and gene mutations [5] despite the stage. The trend is to find evidence of benefit from adjuvant therapy to epidermal growth factor-muted patients, even for early stage of lung cancer (e.g., the Randomized, Double-Blind Trial in Adjuvant NSCLC with Tarceva (RADIANT) trial, double-blind randomized of erlotinib in the adjuvant setting of I–IIIa NSCLC). Moreover, the authors have accurately stated that extended lymphadenectomy is not more morbid than sampling.

As a conclusion, regarding the benefit/risk expected of extended lymphadenectomy and the absence of accuracy of PET/CT for small-size structures, I was expecting the authors to conclude that PET/CT is not relevant for small-size tumor or node metabolic evaluation. A trial evaluating the omission of extended lymphadenectomy in small-size tumors with no lymph node uptake on PET–CT appears unethical and obviously exposes the arm of patient without lymphadenectomy to a loss of chance (risk of under staging and under treatment). In addition, a ‘wait-for–grow-’ attitude for non-uptaking nodes with suspect morphologic characteristics is a misbenefit of technology.

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