True Prevalence of Unforeseen N2 Disease in NSCLC: A Systematic Review + Meta-Analysis

Abstract

Patients with unforeseen N2 (uN2) disease are traditionally considered to have an unfavorable prognosis. As preoperative and intraoperative mediastinal staging improved over time, the prevalence of uN2 changed. In this review, the current evidence on uN2 disease and its prevalence will be evaluated. A systematic literature search was performed to identify all studies or completed, published trials that included uN2 disease until 6 April 2023, without language restrictions. The Newcastle-Ottawa Scale (NOS) was used to score the included papers. A total of 512 articles were initially identified, of which a total of 22 studies met the predefined inclusion criteria. Despite adequate mediastinal staging, the pooled prevalence of true unforeseen pN2 (9387 patients) was 7.97% (95% CI 6.67–9.27%), with a pooled OS after five years (892 patients) of 44% (95% CI 31–58%). Substantial heterogeneity regarding the characteristics of uN2 disease limited our meta-analysis considerably. However, it seems patients with uN2 disease represent a subcategory with a similar prognosis to stage IIb if complete surgical resection can be achieved, and the contribution of adjuvant therapy is to be further explored.

Saving Lives in Thoracic Surgery: Balancing Oncological Radicality and Functional Preservation, Transitioning from Standard Pneumonectomy to Targeted Sublobar Resection

“…Although a conversion to a lobectomy is feasible if lymph node metastasis is detected intraoperatively, a completion lobectomy may pose technical difficulties in patients found to have occult lymph node metastasis after surgery. Recent studies investigating long-term outcomes in patients with an occult N2 after either a lobectomy or a segmentectomy have shown that the type of surgical procedure, either a lobectomy or a segmentectomy, does not significantly affect survival rates; instead, appropriate adjuvant chemotherapy plays a crucial role [40,41]. Therefore, emphasis should be placed on administering adequate adjuvant treatment based on proper staging to improve patient survival rates, rather than solely relying on completion lobectomies.…”

Systematic mediastinal staging in non‐small cell lung cancer: Filling in the guideline evidence gap

“…In the pre‐PET era, upstaging to pN2/3 was observed in up to 25% of patients with T1/2 N0 NSCLC 9 . Consistent use of PET results in reduced post‐operative upstaging to approximately 6%–9%, 8,10–13 though varies according to clinico‐radiologic factors, including tumour size >3 cm (rate unforeseen N2 21%–22% 8,10 ) and cN1 (rate unforeseen N2 17%–25% 14–17 ).…”