When to Consider Invasive Lymph Node Staging in Non-Small-Cell Lung Cancer? A Novel Scoring System Utilising...

Area of Science:

• Oncology
• Radiology
• Nuclear Medicine

Background:

• The maximum standardised uptake value (SUVmax) is a common but controversial metric for staging non-small cell lung cancer (NSCLC) using positron emission tomography/computed tomography (PET/CT).
• Accurate nodal staging is crucial for effective NSCLC treatment planning.

Purpose of the Study:

• To assess the effectiveness of semi-quantitative PET/CT parameters (size, SUVmax, metabolic tumour volume (MTV), total lesion glycolysis (TLG), heterogeneity factor (HF)) for evaluating primary tumours and lymph nodes (LNs) in NSCLC.
• To develop and validate a novel scoring system for improved nodal staging in NSCLC.

Main Methods:

• Retrospective analysis of 319 patients with clinically staged I-III NSCLC diagnosed between 2014 and 2019.
• Collection of patient demographics and PET/CT parameters including SUVmax, MTV, TLG, and HF for primary tumours and LNs.
• Development of a novel scoring system incorporating identified risk factors and visual assessment of LNs.

Main Results:

• Tumour size, SUVmax, MTV, TLG, and HF did not significantly predict LN metastasis individually.
• Non-squamous cell carcinoma, higher LN FDG uptake than the liver, LN size, SUVmax, MTV, and TLG were significant risk factors for metastasis (P<0.0001).
• A novel scoring system with cut-off values (LN size: 1.05cm, SUVmax: 4.055, MTV: 1.805cm³, TLG: 5.485) indicated that a score ≥3 increased metastasis risk 14.33-fold.

Conclusions:

• A novel scoring system effectively identifies lymph node metastasis in NSCLC patients.
• LNs with a score of ≥3 demonstrate a high likelihood of metastasis.
• This scoring system can reduce unnecessary invasive pathological staging procedures.