Exploring indications for anatomic partial lobectomy in the modern era

In this retrospective cohort study, the authors describe their experience performing anatomic partial lobectomy (APL), which was defined as anatomic resection of one or more segments or subsegments (1). This study included more than 3,300 patients at a large cancer center in China, who underwent predominantly thoracoscopic procedures over a 6-year period performed by experienced thoracic surgeons. Three-dimensional reconstruction of preoperative imaging was used to plan the resections, which were classified as simple, moderate, or complex, depending on the number of dissection surfaces and segments/subsegments resected. Outcomes were excellent, with mean operating time of approximately 127 minutes, low overall morbidity, and no reported mortalities. From an oncologic standpoint, 85% of patients underwent systematic mediastinal node evaluation with a median of 11 lymph nodes and 4 lymph node stations resected. This paper reports a large experience performing complex minimally invasive sublobar resection for patients with suspected or confirmed lung cancer and raises important questions regarding the most appropriate application of anatomic sublobar resection in the modern era.

It is relevant to note that there are several key differences between this patient cohort and those individuals described in recently published trials comparing sublobar resection to lobectomy in early-stage lung cancer, namely the CALGB140503/Alliance (2) and JCOG0802 (3) trials. Perhaps most importantly, both trials included patients with confirmed lung cancer, 2 cm or smaller, and in the outer third of the lung parenchyma. JCOG0802 further included only single tumors and excluded basilar segmentectomy. In both studies, patients had not previously received chemotherapy or radiation. By comparison, Qiu et al. report on a more heterogeneous population. More than 20% of patients in this cohort were found to have benign lesions or noninvasive cancers, and up to 25% of patients had multiple primary cancers. The authors describe 1,250 (37%) simple cases (standard segment with one intersegmental dissection plane), 1,383 (41%) moderate complexity cases (segments with multiple dissection planes), and 703 (21%) complex cases involving extended segmentectomy, combined subsegmentectomy, or combined segmentectomy. The authors describe intentional APL being performed for patients who would have tolerated lobectomy and passive APL for those unable to tolerate lobectomy and unsuitable for wedge resection. It remains unclear what proportion of patients underwent sublobar resection for each indication and where tumors were located within the parenchyma. Several patients in the cohort had advanced disease and some had previously undergone neoadjuvant therapy. Finally, this patient population included 68% women and 80% non-smokers, which differs substantially from the typical cohort of lung cancer patients in a Western population. For example, the CALGB140503 cohort included only 9% never smokers; 41% of patients were currently smoking at the time of resection (4). As such, the application of these findings to other patient groups may be limited. There are also limited data regarding other comorbidities that may impact the application of APL to specific patient subgroups.

Differences in surgeon experience may also impact the generalizability of these results. Of the cases described, 93% were performed thoracoscopically, 51% utilized single-port techniques, and authors reported that case complexity increased over time. However, the surgeons included in the study were also highly experienced, performing more than 300 thoracic surgery operations per year. The impact of surgeon experience in this study is underscored by comparisons to recent trial data. Operative times in this series were shorter than those described in JCOG0802, and there was a 0.2% rate of conversion to thoracotomy compared to 6% in CALGB140503. Despite being performed by highly experienced surgeons, APL was still associated with a significant learning curve, with shorter operative times and lower complication rates during the latter portion of the study period. Complex cases were associated with a 2.5-fold increased risk of postoperative complications. Prolonged air leak was the most common complication and chest tubes were left in place for a median of 4 [interquartile range (IQR), 3–6] days. One ventilatory failure was described. It is unclear how generalizable these findings may be when performed elsewhere, perhaps by surgeons with less experience in the conduct of these cases. Furthermore, a higher incidence of prolonged air leak can lead to longer inpatient hospitalizations, higher overall costs and poorer postoperative quality of life (5). In addition, smoking status was associated with a higher risk of complications which is an important consideration given the higher frequency of smoking in Western cohorts and its impact on pulmonary function (6).

Given the technical complexity and potential risk associated with APL, it is important to identify the most appropriate population for its adoption in the modern era. In early 2024, a post-hoc analysis of the CALGB140503 trial demonstrated similar survival after wedge resection compared to segmentectomy and lobectomy for patients with early peripheral lung cancers (4). Based on these results, there may be limited benefit in using more complex anatomic resection techniques over wedge resection in this population. One important consideration is the value of more extensive lymph node evaluation during anatomic dissection. Qiu et al. report a median of 11 nodes evaluated compared to 4 nodes in CALGB140503. In the CALGB140503 post hoc analysis, patients undergoing lobectomy had more lymph nodes evaluated and a higher rate of nodal positivity compared to those undergoing sublobar resection, particularly compared to wedge resection. There was a trend toward higher locoregional recurrence among patients who had wedge resection which may be important as this was a post hoc analysis, not adequately powered to detect significant differences in this area.

For patients not meeting criteria for sublobar resection in recent trials and current clinical guidelines, APL must be used with caution. The complex APL technique described by Qiu may be of most significant benefit for patients with more advanced disease who are unable to tolerate lobectomy and those with multiple primary tumors for which parenchymal sparing is needed. The greater number of lymph nodes dissected/sampled during these operations may increase diagnostic yield, but without definitive differences in nodal upstaging, it is not clear that it will have downstream impact on outcomes. For patients with adequate pulmonary function and more centralized tumors/advanced disease, lobectomy is still preferred over sublobar resection, according to current guidelines and recommendations in the United States (7). For those with small central tumors and high surgical risk, it is important to consider the comparative benefit of alternatives to surgery such radiation. For patients with benign disease requiring surgery, use of less complex, non-anatomic resection may be preferred when feasible. Furthermore, advances in diagnostic and therapeutic approaches may impact the future use of APL. With increasing use of the robotic platform, there may be a less profound learning curve associated with performing more complex anatomic resections. Advances in three-dimensional imaging and robotic bronchoscopy may reduce the need to perform complex anatomic resections for benign and pre-malignant lesions. Novel techniques for nodule marking and localization may also increase the efficacy of identifying small tumors below the pleural surface and make it possible to achieve appropriate margins with non-anatomic resection using minimally invasive techniques when appropriate.

This study characterized perioperative and short-term outcomes after APL for patients with suspected or confirmed lung cancers. The authors demonstrate that this technique is technically feasible in experienced hands, but that a significant learning curve persists, with more complications after complex multi- or sub-segmental resections and among patients who smoke. Several factors, including surgeon experience, tumor size, location, and histology, and patient comorbidities (including smoking) may impact the feasibility of using this approach more broadly. In future studies evaluating the long-term oncologic outcomes of APL, it will be important to stratify results based on tumor stage and indication to ensure accurate comparisons. The primary question that arises from this article centers around understanding when APL is of greatest benefit. Based on recent trial data, wedge resection may be sufficient for well-selected patients with early peripheral tumors and current guidelines in the United States recommend lobectomy for larger or more central tumors in patients with adequate pulmonary function. As a result, APL may offer the most benefit for patients with multiple small primary tumors and those with borderline pulmonary function (8).

Acknowledgments

Funding: None.

Footnote

Provenance and Peer Review: This article was commissioned by the editorial office, Journal of Thoracic Disease. The article has undergone external peer review.

Peer Review File: Available at https://jtd.amegroups.com/article/view/10.21037/jtd-24-272/prf

Conflicts of Interest: Both authors have completed the ICMJE uniform disclosure form (available at https://jtd.amegroups.com/article/view/10.21037/jtd-24-272/coif). M.B.A. serves as an unpaid editorial board member of Journal of Thoracic Disease from August 2024 to July 2026. M.B.A. receives consulting fees from AZ, MSD, Ethicon and BMS; payment for lectures from AZ, MSD and Ethicon. The other author has no conflicts of interest to declare.

Ethical Statement: The authors are accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved.

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