New perspective to evaluate N1 staging: The peripheral lymph node metastasis status of non‐small cell lung cancer

Abstract

Background Lymph node (LN) metastasis status is the decision‐making basis for the surgical procedure and adjuvant therapy modalities. Fewer studies have previously focused on LN metastasis in N1 station, especially on peripheral lymph node (PLN) metastasis in N1 station. This study aimed to reveal the metastasis status of PLN of non‐small cell lung cancer (NSCLC), and investigate its effects on N staging. Methods We retrospectively evaluated a consecutive series of patients who underwent curative resection for histologically confirmed N1 NSCLC. Propensity score matching (PSM) was used to analyze the effects of PLN on N staging. Results A total of 105 patients with confirmed pathological N1 (pN1) stage NSCLC with solitary nodule and without neoadjuvant therapy were enrolled into the study: 55 patients had intraperipheral LN metastasis (IPLNM), and 50 patients had extra‐peripheral LN metastasis (EPLNM). Before PSM analysis, type of location (P = 0.002), surgical procedure (P = 0.008), number of positive LNs (P = 0.029), number of LNs removed (P = 0.010), lobe of lung cancer (P = 0.031), and vascular invasion (P = 0.049) showed significant differences between the two groups. After PSM analysis, statistically there were differences in type of location (P = 0.034), number of positive LNs (P = 0.008) and vascular invasion (P = 0.049) between them. Conclusion PLN metastasis was a quite common pattern of LN metastasis in N1 station of NSCLC. IPLNM occurred more frequently in central NSCLC and NSCLC with vascular invasion, and thoracotomy was likely to secure more accurate PLN staging. Clinicians should pay great attention to PLN dissection. Follow‐up data will be needed in order to detect the prognosis of IPLNM patients.

Clinical evaluation of contrast-enhanced CT combined with PET/CT in diagnosis of mediastinal lymph node metastasis of non-small-cell lung cancer

“… 12 Its prognosis is closely related to the timing of treatment, early detection and timely treatment can present a satisfactory effect. 13 It is believed that 14 NSCLC with different genotypes have different tendencies of lymph node metastasis, which has a great influence on the selection of treatment methods. Yang et al 15 believe that patients with lymph node metastasis and multiple-organ metastasis present poorer prognosis in terms of survival time, and a better understanding of lymph node metastasis can help clinicians better select treatment methods for NSCLC.…”

The impacts of isolated N1 lymph nodes metastasis on prognosis in non-small cell lung cancer: A single-center experience

“…It has been reported that the pathological stage may increase by 2.4% or 11% after a routine or careful pathological examination. [6,16] According to the reports in the literature, N1 definitions are found to be insufficient in the last lung TNM classification. Evaluations in the form of nN, LNR, and combinations of these among themselves and localization are reported to reflect the prognosis more successfully.…”

“…[ 10 , 12 ] There are studies reporting a better outcome of nNa than nNb. [ 6 , 7 , 17 ] In a study, the five-year survival rate was 67.6% in nNa group and 66.6% in nNb group. [ 20 ] In the same study, although there was a better survival tendency in nNa group, there was no significant difference between the groups (p=0.623).…”

“…[ 7 ] Indeed, some studies have reported that LNR can be an independent predictor in operable N1 NSCC cases. [ 6 ] In the study of Wang et al,[ 12 ] the worst five-year survival rate was found in the group with high LNR, compared to the lower group (p<0.0001). In daily practice, however, it may not be an ideal prognostic factor to use the number of lymph nodes directly or in combination, since there may not be enough N1 lymph node excision or examination in all patients due to different surgical experiences.…”

“…Lymph node metastasis is one of the most important prognostic factors in non-small cell lung cancer (NSCLC). [1][2][3][4][5][6] The N part of the Tumor, Node, Metastasis (TNM) system used in lung cancer staging refers to the lymph node status. The N1 lymph node metastasis indicates a prognostically heterogeneous group.…”