Nodal size ranking as a predictor of mediastinal involvement in clinical early-stage non-small cell lung cancer

Abstract

In non-small cell lung cancer (NSCLC) patients, the recommended minimum requirement for an endoscopy-based mediastinal staging procedure is sampling the largest lymph node (LN) in right and left inferior paratracheal, and subcarinal stations. We aimed to analyze the percentage of cases where the largest LN in each mediastinal station was malignant in a cohort of NSCLC patients with mediastinal metastases diagnosed in the lymphadenectomy specimen. Furthermore, we investigated the sensitivity of a preoperative staging procedure in a hypothetical scenario where only the largest LN of each station would have been sampled. Prospective data of patients with mediastinal nodal metastases diagnosed in the lymphadenectomy specimens were retrospectively analyzed. The long-axis diameter of the maximal cut surface of all LNs was measured on hematoxylin and eosin-stained sections. Seven hundred seventy five patients underwent operation and 49 (6%) with mediastinal nodal disease were included. A total of 713 LNs were resected and 119 were involved. Sixty seven nodal stations revealed malignant LNs: in these, the largest LN was malignant in 39 (58%). In a “per patient” analysis, a preoperative staging procedure that sampled only the largest LN would have attained a sensitivity of 0.67; and if the largest and the second largest were sampled, sensitivity would be 0.87. In patients with NSCLC, nodal size ranking is not reliable enough to predict malignancy. In clinical practice, regardless of the preoperative staging method, systematic thorough sampling of all visible LNs is to be recommended over selective random samplings.

Dual-Energy Computed Tomography for the Diagnosis of Mediastinal Lymph Node Metastasis in Lung Cancer Patients: A Preliminary Study

“…Lymph node diameter was measured in this set of images. The short-axis length of mediastinal LNs was measured at the axial plane with the largest short axis 11 . Then, a 10-mm 2 region of interest was placed on mediastinal LNs to measure the attenuation value in 16 sets of virtual monochromatic images (VMIs) (corresponding to the photon energy levels of 40 keV–190 keV at a 10 keV interval) and iodine concentration (IC) in the iodine-based material decomposition images.…”

“…The short-axis length of mediastinal LNs was measured at the axial plane with the largest short axis. 11 Then, a 10-mm 2 region of interest was placed on mediastinal LNs to measure the attenuation value in 16 sets of virtual monochromatic images (VMIs) (corresponding to the photon energy levels of 40 keV-190 keV at a 10 keV interval) and iodine concentration (IC) in the iodine-based material decomposition images. The attenuation value in 40 keV to 190 keV VMIs was used to calculate the slope of the spectral attenuation curve (K) with the formula K = (HU 40keV − HU 190keV )]/(40-190) (wherein HU is the attenuation value of LN measured at single energy levels of 40 and 190 keV, respectively).…”

Mediastinal staging for non-small cell lung cancer

“…The presence of lymph nodes whose size exceed 10 mm on the short axis should be considered a predictor of malignancy. However, results from studies focused in the accuracy of lymph node size for malignancy prediction have demonstrated that size alone is insufficient to confirm or discard metastatic infiltration of lymph nodes because of the low sensitivity (55%) reported for this technique (1)(2)(3)(4)(5)(6)(7)(8)(9)15). Additionally, the clinical relevance of nodal enlargement is limited because metastases have been found in about 20% of lymph nodes with dimensions under 1 cm on the short axis (6).…”

Preoperative staging of the mediastinum is an essential and multidisciplinary task

“…Several authors have classified the levels of thoroughness in four categories ranging from A (optimal) to D (poorest) 34 . For surgical methods, level A is restricted to lymphadenectomy and implies complete resection of nodal stations according to the IASLC lymph node map 35 : stations 1 (low cervical, sternal notch), 2L (left upper paratracheal), 2R (right upper paratracheal), 3 (prevascular (3a)) and retrotracheal (3p)), 4R (right lower paratracheal), 4L (left lower paratracheal), 7 (subcarinal) and 8 (right (R)/left (L) paraoesophageal); and 5 (subaortic) and 6 (paraaortic) for left upper lobe tumours (Fig. 4).…”