Does surgical margin affect recurrence and survival after sublobar pulmonary resection for lung cancer?

A best evidence topic in thoracic surgery was written according to a structured protocol. The question addressed was: How does surgical margin distance affect recurrence and survival after sublobar pulmonary resection for lung cancer? Altogether, 172 papers were found using the search strategy, of which 12 studies with 1946 stage I non-small-cell lung cancer (NSCLC) patients using sublobar resection (wedge resection or segmentectomy) represented to be the best evidence to answer the clinical question. The authors, journal, date and country of publication, patient group studied, study type, relevant outcomes and results of these papers were tabulated. Overall, 11 cohort studies and 1 prospective study were included. Four cohort studies demonstrated positive prognostic significance of surgical margin with specific cut-off points in each paper (ranged from 9 to 15 mm). Two retrospective studies and 1 prospective study found that a margin-to-tumour ratio of ≥1 was associated with better cytology and prognosis results. Other 5 studies showed that larger margin distance provided a favourable prognosis for NSCLC patients with poor-prognostic factors, including solid-dominant type, high invasive component size and Spread through Air Spaces-positive subtype. After reviewing all the included articles, we conclude that the standard of margin distance of >10 mm or margin-to-tumour ratio  ≥ 1 should be recommended for stage I NSCLC patients undergoing sublobar resection, especially in wedge resection. Patients with poor-prognostic factors like solid-predominant tumour or non-lepidic adenocarcinoma may benefit from larger margin distance and the proper margin distance for them still needs to be determined. For Spread through Air Spaces-positive patients, sublobar resection may not be the alternative to lobectomy.