The Incidence of Node-Positive Non-small-Cell Lung Cancer Undergoing Sublobar Resection and the Role of Radiation in Its Management

Abstract

Purpose: To identify the incidence, preoperative risk factors, and prognosis associated with pathologically positive lymph node (pN+) in patients undergoing a sub-lobar resection (SLR). Methods: This is a retrospective study using the National Cancer Database (NCDB) from 2004 to 2014 analyzing SLR excluding those with any preoperative chemotherapy and/or radiation, follow-up <3 months, stage IV disease, or >1 tumor nodule. Multivariable modeling (MVA) was used to determine factors associated with overall survival (OS). Propensity score matching (PSM) was used to determine preoperative risk factors for pN+ in patients having at least one node examined to assess radiation's effect on OS in those patients with pN+ and to determine whether SLR was associated with inferior OS as compared to lobectomy for each nodal stage. Results: A total of 40,202 patients underwent SLR, but only 58.3% had one lymph node examined. Then, 2,615 individuals had pN+ which decreased progressively from 15.1% in 2004 to 8.9% in 2014 (N1, from 6.3 to 3.0%, and N2, from 8.4 to 5.9%). A lower risk of pN+ was noted for squamous cell carcinomas, bronchioloalveolar adenocarcinoma (BAC), adenocarcinomas, and right upper lobe locations. In the pN+ group, OS was worse without chemotherapy or radiation. Radiation was associated with a strong trend for OS in the entire pN+ group (p = 0.0647) which was largely due to the effects on those having N2 disease (p = 0.009) or R1 resections (p = 0.03), but not N1 involvement (p = 0.87). PSM noted that SLR was associated with an inferior OS as compared to lobectomy by nodal stage in the overall patient population and even for those with tumors <2 cm. Varlotto et al. Incidence and Outcomes of SLRs With Positive Nodes Conclusion: pN+ incidence in SLRs has decreased over time. SLR was associated with inferior OS as compared to lobectomy by nodal stage. Radiation appears to improve the OS in patients undergoing SLR with pN+, especially in those with N2 nodal involvement and/or positive margins.

Commentary: The Incidence of Node-Positive Non-small-Cell Lung Cancer Undergoing Sublobar Resection and the Role of Radiation in Its Management

“…This suboptimal staging is likely responsible for the observed reduced long-term oncological outcome of patients undergoing sublobar resections due to an upstaging failure effect. In fact, the authors ( 4 ) showed a nodal upstaging rate ranging from 7.6% for nodules under 2 cm to 15% for nodules over 2 cm treated with sublobar resection.…”

“…It is known that anatomical segmentectomies performed by a minimally invasive approach are technically demanding procedures, with the expected result that much more wedge resections instead of anatomical segments have been done to avoid open surgery (4).…”

“…The paper by Varlotto et al ( 4 ) reveals that almost half of the patients undergoing sublobar resection received no removal of a single hilar or mediastinal lymph nodes. This suboptimal staging is likely responsible for the observed reduced long-term oncological outcome of patients undergoing sublobar resections due to an upstaging failure effect.…”

“…The paper by Varlotto et al (4), through a retrospective analysis of the American National Cancer Database (NCDB), focuses the attention on patients undergoing sublobar resection for non-small cell lung cancer with positive hilar or mediastinal lymph nodes and tries to assess the incidence, risk factors, and prognosis of this particular circumstance, evaluating the potential role of postoperative radiation therapy for these patients.…”

“…The article by Varlotto et al ( 4 ) is an occasion to reflect on the consequences of a suboptimal situation in which a sublobar resection is undertaken despite the oncological criteria are not followed.…”