Multicenter prospective study of sublobar resection for c-stage I non-small cell lung cancer patients unable to undergo lobectomy (KLSG-0801): complete republication

Should sublobar resection be offered for screening-detected lung nodules?

The increasing use of low-dose CT for screening for lung cancer will inevitably identify many small, asymptomatic lung nodules and ground-glass opacities (GGOs). Current guidelines for the management of screening-detected lesions tend to advise a conservative approach based on serial imaging and intervention only if ‘suspicious’ features emerge. However, more recent developments in thoracic surgery and in the understanding of the screening-detected lesions themselves prompt some pertinent questions over this conservatism. Is CT surveillance sufficiently reliable to exclude malignancy? Is it really necessary to hold back on operative biopsy and resection given modern surgical safety and efficacy? Is the option for early surgical therapy a viable one—especially with the availability of sublobar resection today? Modern data suggests that the risk of inaction for some screening-detected lesions may be higher than expected, whereas the potential harm of surgical intervention may be substantially reduced by sublobar resection and the latest minimally invasive surgical techniques. A more pro-active approach towards offering surgery for screening-detected lesions should now be considered.

Video-assisted thoracoscopic surgery as the gold standard for lung cancer surgery

Surgical resection remains the only effective means of cure in the vast majority of patients with early-stage lung cancer. It can be performed via a traditional open approach (particularly thoracotomy) or a minimally invasive approach. VATS is 'keyhole' surgery in the chest, and was first used for lung cancer resection in the early 1990s. Since then, a large volume of evolving clinical evidence has confirmed that VATS lung cancer resection offered proven safety and feasibility, better patient-reported post-operative outcomes, less surgical trauma as quantified by objective outcome measures and equivalent or better survival than open surgery. This has firmly established VATS as the surgical approach of choice for early-stage lung cancer today. Although impressive new non-surgical lung cancer therapies have emerged in recent years, VATS is also being constantly rejuvenated by the development of 'next generation' VATS techniques, the refinement of VATS sublobar resection for selected patients, the utilization of bespoke post-operative recovery programmes for VATS and the synthesis of VATS into multi-modality lung cancer therapy. There is little doubt that VATS will remain as the gold standard for lung cancer surgery for the foreseeable future.

Surgery or stereotactic body radiotherapy for metachronous primary lung cancer? A propensity score matching analysis

OBJECTIVE

We compared outcomes after surgery or stereotactic body radiotherapy (SBRT) among patients with metachronous primary lung cancer (MPLC).

METHODS

Patients with MPLC were treated with either surgery (2008-2018) or SBRT (2010-2018). We used propensity score matching (PSM) to reduce bias from various clinicopathological factors. MPLC was defined by the Martini and Melamed criteria.

RESULTS

Of 77 patients, 51 underwent surgery and 26 received SBRT. Most median clinicopathological characteristics did not significantly differ between the surgery and SBRT groups (male sex: 67% vs 65%; age: 73 vs 77 years; time after first surgery: 6.2 vs 4.7 years; lobectomy as first procedure: 82% vs 85%; second tumor size: 11 vs 12 mm; clinical stage I: 96% vs 100%; CEA: 2.9 vs 3.0 ng/ml). However, the surgery group had significantly more ipsilateral second tumors (n = 71, 58%, P = 0.003), better performance status (P = 0.03), and preserved lung function (P = 0.02). Surgery, thus, tended to be selected for patients with good physical function and for the MPLC in the contralateral side. Five-year overall survival did not significantly differ between the surgery and SBRT groups, either before PSM (86.5% vs 65.8%, P = 0.24, log-rank) or after PSM (100% vs 84.4%, P = 0.73).

CONCLUSIONS

Surgery and SBRT for MPLC patients are safe and feasible treatments with similar outcomes. However, this finding should be verified by a random controlled trial with a larger study cohort.

Oncologic Outcomes of Surgery Versus SBRT for Non-Small-Cell Lung Carcinoma: A Systematic Review and Meta-analysis

BACKGROUND

The optimal treatment of stage I non-small-cell lung carcinoma is subject to debate. The aim of this study was to compare overall survival and oncologic outcomes of lobar resection (LR), sublobar resection (SR), and stereotactic body radiotherapy (SBRT).

METHODS

A systematic review and meta-analysis of oncologic outcomes of propensity matched comparative and noncomparative cohort studies was performed. Outcomes of interest were overall survival and disease-free survival. The inverse variance method and the random-effects method for meta-analysis were utilized to assess the pooled estimates.

RESULTS

A total of 100 studies with patients treated for clinical stage I non-small-cell lung carcinoma were included. Long-term overall and disease-free survival after LR was superior over SBRT in all comparisons, and for most comparisons, SR was superior to SBRT. Noncomparative studies showed superior long-term overall and disease-free survival for both LR and SR over SBRT. Although the papers were heterogeneous and of low quality, results remained essentially the same throughout a large number of stratifications and sensitivity analyses.

CONCLUSION

Results of this systematic review and meta-analysis showed that LR has superior outcomes compared to SBRT for cI non-small-cell lung carcinoma. New trials are underway evaluating long-term results of SBRT in potentially operable patients.

Similar-cases-based planning approaches with beam angle optimizations using water equivalent path length for lung stereotactic body radiation therapy

This study aimed to propose automated treatment planning approaches based on similar cases with beam angle optimizations using water equivalent path length (WEPL) to avoid lung and rib doses for lung stereotactic body radiation therapy (SBRT). Similar cases to an objective case were defined as cases, which were close to the objective case with respect to the Euclidean distances based on geometrical features. Initial similar-case-based (ISC) plans were generated by applying lung SBRT plans of similar cases to objective cases. Similar cases were selected using the Euclidean distances based on lung shape and geometrical features from a radiation treatment planning database with 174 cases. Beam angles of the ISC plans were optimized using a greedy algorithm based on a cost function to include absorbed doses in the lung and ribs in the WEPL. The 12 dose evaluation indices for the planning target volume, lung, spinal cord, and ribs were evaluated in the original plans, ISC plans, and optimized similar-case-based (OSC) plans with and without WEPL for 20 test cases to investigate its dosimetric impact. These findings revealed that V10 and the mean dose for the lung and V20, V30, and V40 for the ribs in the OSC plan with WEPL improved more significantly than those in the original and ISC plans. This study indicates a potential of similar cases, whose beam angle configurations were optimized with WEPL to avoid lung and rib doses in lung SBRT plans.

Optimal sublobar resection for c-stage I non-small cell lung cancer: significance of margin distance to tumor size ratio and margin cytology (Supplementary analysis of KLSG-0801): complete republication

BACKGROUND

Sublobar resection for lung cancer is associated with a higher risk of recurrence than that of lobectomy; we evaluated the factors considered to be predictors of recurrence.

METHODS

By analyzing multicenter prospective studies of sublobar resection for patients with c-stage I non-small lung cancer who were unable to undergo lobectomy (KLSG-0801), we investigated the relationship between (1) tumor location (TL) and margin distance from the stump (MD), (2) the MD/tumor size (TS) ratio and prognosis, (3) and the margin cytology (MC) and prognosis.

RESULTS

The correlation between TS and MD was statistically significant in cases of easily resectable regions defined by Lewis' classification (n = 18). However, there was no correlation in difficult-to-resect regions (n = 14). Among cases of recurrence, the MD/TS ratio was less than 1. The 3-year survival rate was 100% for patients with MD/TS > 1 (n = 12), 59.7% for patients with MD/TS ≤ 1 (n = 20) (p = 0.06), 88.1% in cases of negative MC (n = 18), and 20% in cases of positive MC (n = 5) (p = 0.001).

CONCLUSION

Cases with positive MC had a significantly worse prognosis than those with negative MC. It may be difficult to secure an MD greater than the TS in a difficult-to-resect region according to Lewis' classification.

Validating margin status in lung wedge resection for clinical stage I non-small cell lung cancer

Stage I non-small cell lung cancer (NSCLC) is a localized disease without metastasis; therefore, it can be treated effectively with local therapies. Pulmonary resection is the most frequent treatment, performed as pulmonary wedge resection, segmentectomy, lobectomy, or pneumonectomy. Some retrospective clinical studies of pulmonary wedge resection suggest that its outcome may be inferior to that of anatomical pulmonary resection, whereas other recent studies, which assess surgical margin status, leveled acceptable outcomes. Since the outcome of pulmonary wedge resection for lung cancer may depend on tumor size, distance from the surgical margin to the tumor, tumor size/margin distance ratio, and margin cytology results, a prospective study assessing these parameters is ongoing. This will allow us to identify the clinical implications of these factors and predict which patients are likely to have a good outcome.