Late Recurrence of Completely Resected Stage I-IIIA Lung Adenocarcinoma.

OBJECTIVE: Research into the risk factors associated with late recurrence (>2 years after surgery) of lung adenocarcinoma (LUAD) is limited. We investigated the incidence of and clinicopathologic and genomic features associated with late recurrence of resected stage I-IIIA LUAD. METHODS: We performed a retrospective analysis of patients with completely resected pathologic stage I-IIIA LUAD (2010-2019). Patients with a history of lung cancer, neoadjuvant therapy, or mucinous or noninvasive LUAD, or with follow-up of <2 years were excluded. Cox and logistic regression modeling were used to compare clinicopathologic variables among patients with no, early (≤2 years), and late recurrence. Comparisons of genomic mutations were corrected for multiple testing. RESULTS: Of the 2349 patients included, 537 developed a recurrence during follow-up. Most recurrences (55% [297/537]) occurred early; 45% (240/537) occurred late. A larger proportion of late recurrences than early recurrences were locoregional (37% vs. 29%; p=0.047). Patients with late recurrence had more aggressive pathologic features (IASLC grade 2 and 3, lymphovascular invasion, visceral pleural invasion) and higher stage than patients without recurrence. Pathologic features were similar between patients with early and late recurrence, except stage IIIA disease was more common in the early cohort. No genomic mutations were associated with late recurrence. CONCLUSIONS: Late recurrence of LUAD following resection is more common than previously reported. Patients without disease >2 years after surgery who had aggressive pathologic features at the time of resection have an elevated risk of recurrence and may benefit from more-aggressive follow-up.

Characterizing a learning curve for robotic-assisted bronchoscopy: Analysis of skills acquisition in a high-volume academic center.

OBJECTIVE: Shape-sensing robotic-assisted bronchoscopy (ssRAB) is an emerging technology for the sampling of pulmonary lesions. We seek to characterize the ssRAB learning curve at an academic center. METHODS: SsRAB procedures performed by 9 proceduralists at a single institution were analyzed. Cumulative sum analyses were performed to examine diagnostic sampling and procedure time over each operator's first 50 cases, with the acceptable yield threshold set to 73%. RESULTS: During the study period, 442 patients underwent sampling of 551 lesions. Each operator sampled 61 (IQR, 60-63) lesions. Lesion size was 1.90 cm (IQR, 1.33-2.80). The median procedure time for single-target cases decreased from 62 minutes during the first 10 cases to 39 minutes after case 40 (P<0.001). The overall diagnostic yield was 72% (range, 58-83%). Six of 9 operators achieved proficiency over the study period. An aggregated cumulative sum analysis of those who achieved competency demonstrated a steep improvement between lesions 1 and 21 and crossing of the competency threshold by lesion 25. Temporal analysis of yield-related lesion characteristics demonstrated that at approximately lesion 20, more challenging lesions were increasingly targeted, as evidenced by smaller target size, higher rates of unfavorable radial endobronchial ultrasound views and a negative bronchus sign. CONCLUSIONS: Skills acquisition in ssRAB is variable. Approximately half of proceduralists become facile with the technology within 25 lesions. After the initial learning phase, operators increasingly target lesions with more challenging features. Overall, these findings can inform certification and competency standards and provide new users with expectations related to performance over time.

Outcomes of Patients Undergoing Segmentectomy for Occult Node-Positive Clinical Stage IA Lung Cancer.

BACKGROUND: Results of recent clinical trials suggest segmentectomy may be an acceptable alternative to lobectomy for selected patients with early-stage non-small cell lung cancer (NSCLC). Increased use of segmentectomy may result in a concomitant increase in occult node-positive (N+) disease on surgical pathology. The optimal management for such patients remains unknown. METHODS: Clinicopathologic data were abstracted from a prospective institutional database to identify patients with pathologic N+ disease after segmentectomy for cT1N0M0 NSCLC. Propensity score matching identified a comparable lobectomy cohort for assessment of cumulative incidence of recurrence and overall survival (OS). RESULTS: Of 759 included patients, 27 (4%) had nodal upstaging on final pathology. Of these, 4 (15%) had skip metastasis to N2 stations, and 20 (74%) received adjuvant therapy; no completion lobectomies were performed. Ten patients (37%) had recurrence: 3 isolated locoregional (11%) and 7 distant (26%). The median time to recurrence among patients with recurrence was 1.8 years; OS after recurrence was 3.4 years. After 5:1 matching with 109 lobectomy patients, all variables were balanced between the groups, except pathologic N2 stage and open surgical approach. Five-year cumulative incidence of recurrence was not significantly different between segmentectomy and lobectomy (42% vs 52%; Gray's p=0.1). Five-year OS (63% and 50%) and rate of locoregional recurrence (12% vs. 13%) were not statistically different between the groups. CONCLUSIONS: Patients with occult N+ disease after segmentectomy for cT1N0M0 NSCLC had limited isolated locoregional recurrences and similar outcomes as patients who underwent lobectomy. Lobectomy may not provide an advantage in these patients.

Determinants of radiation exposure during mobile cone-beam CT-guided robotic-assisted bronchoscopy.

BACKGROUND AND OBJECTIVE: Robotic-assisted bronchoscopy (RAB) is an emerging modality to sample pulmonary lesions. Cone-beam computed tomography (CBCT) can be incorporated into RAB. We investigated the magnitude and predictors of patient and staff radiation exposure during mobile CBCT-guided shape-sensing RAB. METHODS: Patient radiation dose was estimated by cumulative dose area product (cDAP) and cumulative reference air kerma (cRAK). Staff equivalent dose was calculated based on isokerma maps and a phantom simulation. Patient, lesion and procedure-related factors associated with higher radiation doses were identified by logistic regression models. RESULTS: A total of 198 RAB cases were included in the analysis. The median patient cDAP and cRAK were 10.86 Gy cm2 (IQR: 4.62-20.84) and 76.20 mGy (IQR: 38.96-148.38), respectively. Among staff members, the bronchoscopist was exposed to the highest median equivalent dose of 1.48 µSv (IQR: 0.85-2.69). Both patient and staff radiation doses increased with the number of CBCT spins and targeted lesions (p < 0.001 for all comparisons). Patient obesity, negative bronchus sign, lesion size <2.0 cm and inadequate sampling by on-site evaluation were associated with a higher patient dose, while patient obesity and inadequate sampling by on-site evaluation were associated with a higher bronchoscopist equivalent dose. CONCLUSION: The magnitude of patient and staff radiation exposure during CBCT-RAB is aligned with safety thresholds recommended by regulatory authorities. Factors associated with a higher radiation exposure during CBCT-RAB can be identified pre-operatively and solicit procedural optimization by reinforcing radiation protective measures. Future studies are needed to confirm these findings across multiple institutions and practices.

Novel Insights Into the International Association for the Study of Lung Cancer Grading System for Lung Adenocarcinoma.

The new grading system for lung adenocarcinoma proposed by the International Association for the Study of Lung Cancer (IASLC) defines prognostic subgroups on the basis of histologic patterns observed on surgical specimens. This study sought to provide novel insights into the IASLC grading system, with particular focus on recurrence-specific survival (RSS) and lung cancer-specific survival among patients with stage I adenocarcinoma. Under the IASLC grading system, tumors were classified as grade 1 (lepidic predominant with <20% high-grade patterns [micropapillary, solid, and complex glandular]), grade 2 (acinar or papillary predominant with <20% high-grade patterns), or grade 3 (≥20% high-grade patterns). Kaplan-Meier survival estimates, pathologic features, and genomic profiles were investigated for patients whose disease was reclassified into a higher grade under the IASLC grading system on the basis of the hypothesis that they would strongly resemble patients with predominant high-grade tumors. Overall, 423 (29%) of 1443 patients with grade 1 or 2 tumors classified based on the predominant pattern-based grading system had their tumors upgraded to grade 3 based on the IASLC grading system. The RSS curves for patients with upgraded tumors were significantly different from those for patients with grade 1 or 2 tumors (log-rank P < .001) but not from those for patients with predominant high-grade patterns (P = .3). Patients with upgraded tumors had a similar incidence of visceral pleural invasion and spread of tumor through air spaces as patients with predominant high-grade patterns. In multivariable models, the IASLC grading system remained significantly associated with RSS and lung cancer-specific survival after adjustment for aggressive pathologic features such as visceral pleural invasion and spread of tumor through air spaces. The IASLC grading system outperforms the predominant pattern-based grading system and appropriately reclassifies tumors into higher grades with worse prognosis, even after other pathologic features of aggressiveness are considered.

A Real-World Assessment of Stage I Lung Cancer Through Electronic Nose Technology.

INTRODUCTION: Electronic nose (E-nose) technology has reported excellent sensitivity and specificity in the setting of lung cancer screening. However, the performance of E-nose specifically for early-stage tumors remains unclear. Therefore, the aim of our study was to assess the diagnostic performance of E-nose technology in clinical stage I lung cancer. METHODS: This phase IIc trial (NCT04734145) included patients diagnosed with a single greater than or equal to 50% solid stage I nodule. Exhalates were prospectively collected from January 2020 to August 2023. Blinded bioengineers analyzed the exhalates, using E-nose technology to determine the probability of malignancy. Patients were stratified into three risk groups (low-risk, [<0.2]; moderate-risk, [≥0.2-0.7]; high-risk, [≥0.7]). The primary outcome was the diagnostic performance of E-nose versus histopathology (accuracy and F1 score). The secondary outcome was the clinical performance of the E-nose versus clinicoradiological prediction models. RESULTS: Based on the predefined cutoff (<0.20), E-nose agreed with histopathologic results in 86% of cases, achieving an F1 score of 92.5%, based on 86 true positives, two false negatives, and 12 false positives (n = 100). E-nose would refer fewer patients with malignant nodules to observation (low-risk: 2 versus 9 and 11, respectively; p = 0.028 and p = 0.011) than would the Swensen and Brock models and more patients with malignant nodules to treatment without biopsy (high-risk: 27 versus 19 and 6, respectively; p = 0.057 and p < 0.001). CONCLUSIONS: In the setting of clinical stage I lung cancer, E-nose agrees well with histopathology. Accordingly, E-nose technology can be used in addition to imaging or as part of a "multiomics" platform.

Leveraging the pleural space for anticancer therapies in pleural mesothelioma.

Most patients with pleural mesothelioma (PM) present with symptomatic pleural effusion. In some patients, PM is only detectable on the pleural surfaces, providing a strong rationale for intrapleural anticancer therapy. In modern prospective studies involving expert radiological staging and specialist multidisciplinary teams, the population incidence of stage I PM (an approximate surrogate of pleura-only PM) is higher than in historical retrospective series. In this Viewpoint, we advocate for the expansion of intrapleural trials to serve these patients, given the paucity of data supporting licensed systemic therapies in this setting and the uncertainties involved in surgical therapy. We begin by reviewing the unique anatomical and physiological features of the PM-bearing pleural space, before critically appraising the evidence for systemic therapies in stage I PM and previous intrapleural PM trials. We conclude with a summary of key challenges and potential solutions, including optimal trial designs, repurposing of indwelling pleural catheters, and new technologies.

A New Functional Threshold for Minimally Invasive Lobectomy.

OBJECTIVE: To assess the performance of a lower predicted postoperative (ppo) forced expiratory volume in 1 second (FEV1) or diffusion capacity of the lung for carbon monoxide (DLCO) (ppoFEV1/ppoDLCO) threshold to predict cardiopulmonary complications after minimally invasive surgery (MIS) lobectomy. SUMMARY BACKGROUND DATA: Although MIS is associated with better postoperative outcomes than open surgery, MIS uses risk-assessment algorithms developed for open surgery. Moreover, several different definitions of cardiopulmonary complications are used for assessment. METHODS: All patients who underwent MIS lobectomy for clinical stage I-II lung cancer from 2018 to 2022 at our institution were considered. The performance of a ppoFEV1/ppoDLCO threshold of <45% was compared against that of the current guideline threshold of <60%. Three different definitions of cardiopulmonary complications were compared: Society of Thoracic Surgeons (STS), European Society of Thoracic Surgeons (ESTS), and Berry et al. RESULTS: In 946 patients, the ppoFEV1/ppoDLCO threshold of <45% was associated with a higher proportion correctly classified (79% [95% CI, 76%-81%] vs. 65% [95% CI, 62%-68%]; P<0.001). The complication with the biggest difference in incidence between ppoFEV1/ppoDLCO of 45%-60% and >60% was prolonged air leak (33 [13%] vs. 34 [6%]; P<0.001). The predicted probability curves for cardiopulmonary complications were higher for the STS definition than for the ESTS or Berry definitions across ppoFEV1 and ppoDLCO values. CONCLUSIONS: The ppoFEV1/ppoDLCO threshold of <45% more accurately classified patients for cardiopulmonary complications after MIS lobectomy, emphasizing the need for updated risk-assessment guidelines for MIS lobectomy to optimize additional cardiopulmonary function evaluation.

High-risk features associated with recurrence in stage I lung adenocarcinoma.

OBJECTIVE: There is a lack of knowledge regarding the use of prognostic features in stage I lung adenocarcinoma (LUAD). Thus, we investigated clinicopathologic features associated with recurrence after complete resection for stage I LUAD. METHODS: We performed a retrospective analysis of patients with pathologic stage I LUAD who underwent R0 resection from 2010 to 2020. Exclusion criteria included history of lung cancer, induction or adjuvant therapy, noninvasive or mucinous LUAD, and death within 90 days of surgery. Fine and Gray competing-risk regression assessed associations between clinicopathologic features and disease recurrence. RESULTS: In total, 1912 patients met inclusion criteria. Most patients (1565 [82%]) had stage IA LUAD, and 250 developed recurrence: 141 (56%) distant and 109 (44%) locoregional only. The 5-year cumulative incidence of recurrence was 12% (95% CI, 11%-14%). Higher maximum standardized uptake value of the primary tumor (hazard ratio [HR], 1.04), sublobar resection (HR, 2.04), higher International Association for the Study of Lung Cancer grade (HR, 5.32 [grade 2]; HR, 7.93 [grade 3]), lymphovascular invasion (HR, 1.70), visceral pleural invasion (HR, 1.54), and tumor size (HR, 1.30) were independently associated with a hazard of recurrence. Tumors with 3 to 4 high-risk features had a higher cumulative incidence of recurrence at 5 years than tumors without these features (30% vs 4%; P < .001). CONCLUSIONS: Recurrence after resection for stage I LUAD remains an issue for select patients. Commonly reported clinicopathologic features can be used to define patients at high risk of recurrence and should be considered when assessing the prognosis of patients with stage I disease.

Pro: "Is Spread Through Air Spaces an In Vivo Phenomenon or an Inducible Artifact?"

In this PRO-CON debate, you will read very different perspectives about a simple question regarding an observation under the microscope: What is the significance of tumor cells in the air spaces of the lung parenchyma beyond the tumor edge of a resected lung cancer? An important underlying question is whether this entire PRO-CON debate is a mere academic exercise or whether spread through air spaces (STAS), as currently defined, describes a clinically useful phenomenon. The journey of STAS began with a complete paradigm shift to reverse the thinking that all air space tumor cells beyond the edge of lung cancers are an artifact. This led to a new concept where STAS could be separated from artifacts with a definition that has proven to be clinically useful. As with any major change in thinking, it is understandable that there would be some disagreement with this paradigm shift. Nevertheless, after a decade since it was described, many pathologists and clinicians around the world have found STAS to provide important information about the behavior of lung cancer. Numerous PRO-STAS articles supporting the usefulness of STAS have been published with clinical data on many thousands of patients from numerous institutions all over the world. In contrast, for the CON-STAS articles, widespread international representation and data are limited. It is now difficult to ignore the numerous reports and is reasonable to consider how to use the presence of STAS in clinical decisions. Hopefully, this PRO-CON debate will further stimulate clinical and scientific investigations aimed at a better understanding of STAS.

The Emerging Role of Immunotherapy in Resectable Non-Small Cell Lung Cancer.

BACKGROUND: Despite surgical resection, long-term survival of patients with resectable non-small cell lung cancer (NSCLC) remains poor. Adjuvant chemotherapy, the standard of care for locally advanced NSCLC, provides a marginal 5.4% benefit in survival. Immune checkpoint inhibitors (ICIs) have shown a significant survival benefit in some patients with advanced NSCLC and are being evaluated for perioperative use in resectable NSCLC. METHODS: We conducted a literature search using the PubMed online database to identify clinical trials of immunotherapy in resectable NSCLC and studies analyzing biomarkers and immune priming strategies. RESULTS: Building on previous phase I and II trials, randomized phase III trials have shown efficacy of neoadjuvant nivolumab, perioperative pembrolizumab, adjuvant atezolizumab, and adjuvant pembrolizumab in the treatment of NSCLC with improvement of event-free/disease-free survival of 24% to 42%, leading to United States Food and Drug Administration approval of these drugs in the treatment of resectable NSCLC. Three additional phase III trials have also recently reported the use of immunotherapy both before and after surgery, with pathologic complete response rates of 17% to 25%, significantly better than chemotherapy alone. Perioperative ICI therapy has comparable perioperative morbidity to chemotherapy alone and does not impair surgical outcomes. CONCLUSIONS: Perioperative immunotherapy, in combination with chemotherapy, is safe and improves outcomes in patients with resectable NSCLC. Questions regarding patient selection, the need for adjuvant ICI therapy after neoadjuvant chemoimmunotherapy, and the duration of perioperative immunotherapy remain to be answered by future trials.

Comparison of Immunohistochemistry, Next-generation Sequencing and Fluorescence In Situ Hybridization for Detection of MTAP Loss in Pleural Mesothelioma.

9p21 deletions involving MTAP/CDKN2A genes are detected in diffuse pleural mesotheliomas (DPM) but are absent in benign mesothelial proliferations. Loss of MTAP expression by immunohistochemistry (IHC) is well accepted as a surrogate for 9p21 deletion to support a diagnosis of DPM. Accurate interpretation can be critical in the diagnosis of DPM, but variations in antibody performance may impact interpretation. The objectives of this study were to compare the performance of MTAP monoclonal antibodies (mAbs) EPR6893 and 1813 and to compare MTAP expression by IHC with 9p21 copy number status in DPM. Cytoplasmic expression of MTAP IHC with mAbs EPR6893 (ab126770; Abcam) and 1813 (NBP2-75730, Novus Biologicals) was evaluated in 56 DPM (47 epithelioid, 7 biphasic, and 2 sarcomatoid) profiled by targeted next-generation sequencing. 9p21 Copy number status was assessed by Fraction and Allele-Specific Copy Number Estimates from Tumor Sequencing (FACETS) analysis and also by CDKN2A fluorescence in situ hybridization in discrepant cases when material was available. MTAP mAb 1813 showed stronger immunoreactivity, more specific staining, and no equivocal interpretations compared to mAb EPR6893 which showed equivocal staining in 19 (34%) of cases due to weak or heterogenous immunoreactivity, lack of definitive internal positive control, and/or nonspecific background staining. MTAP expression with mAb 1813 showed near perfect agreement with 9p21 copy number by combined FACETS/fluorescence in situ hybridization calls (κ = 0.85; 95% CI, 0.71-0.99; P < .001). MTAP IHC with mAb 1813 was 96% sensitive, 86% specific, and 93% accurate for 9p21 homozygous deletion. The findings of this study suggest that interpretation of MTAP IHC is improved with mAb 1813 because mAb EPR6893 was often limited by equivocal interpretations. We show that MTAP IHC and molecular assays are complementary in detecting 9p21 homozygous deletion. MTAP IHC may be particularly useful for low tumor purity samples and in low-resource settings.

Quantifying Interrater Agreement and Reliability Between Thoracic Pathologists: Paradoxical Behavior of Cohen's Kappa in the Presence of a High Prevalence of the Histopathologic Feature in Lung Cancer.

Introduction: Cohen's kappa is often used to quantify the agreement between two pathologists. Nevertheless, a high prevalence of the feature of interest can lead to seemingly paradoxical results, such as low Cohen's kappa values despite high "observed agreement." Here, we investigate Cohen's kappa using data from histologic subtyping assessment of lung adenocarcinomas and introduce alternative measures that can overcome this "kappa paradox." Methods: A total of 50 frozen sections from stage I lung adenocarcinomas less than or equal to 3 cm in size were independently reviewed by two pathologists to determine the absence or presence of five histologic patterns (lepidic, papillary, acinar, micropapillary, solid). For each pattern, observed agreement (proportion of cases with concordant "absent" or "present" ratings) and Cohen's kappa were calculated, along with Gwet's AC1. Results: The prevalence of any amount of the histologic patterns ranged from 42% (solid) to 97% (acinar). On the basis of Cohen's kappa, there was substantial agreement for four of the five patterns (lepidic, 0.65; papillary, 0.67; micropapillary, 0.64; solid, 0.61). Acinar had the lowest Cohen's kappa (0.43, moderate agreement), despite having the highest observed agreement (88%). In contrast, Gwet's AC1 values were close to or higher than Cohen's kappa across patterns (lepidic, 0.64; papillary, 0.69; micropapillary, 0.71; solid, 0.73; acinar, 0.85). The proportion of positive versus negative agreement was 93% versus 50% for acinar. Conclusions: Given the dependence of Cohen's kappa on feature prevalence, interrater agreement studies should include complementary indices such as Gwet's AC1 and proportions of specific agreement, especially in settings with a high prevalence of the feature of interest.

Management of Pericardial Effusion in Patients With Solid Tumor: An Algorithmic, Multidisciplinary Approach Results in Reduced Mortality After Paradoxical Hemodynamic Instability.

OBJECTIVE: This study compared outcomes in patients with solid tumor treated for pericardial effusion with surgical drainage versus interventional radiology (IR) percutaneous drainage and compared incidence of paradoxical hemodynamic instability (PHI) between cohorts. BACKGROUND: Patients with advanced-stage solid malignancies may develop large pericardial effusions requiring intervention. PHI is a fatal and underreported complication that occurs following pericardial effusion drainage. METHODS: Clinical characteristics and outcomes were compared between patients with solid tumors who underwent s urgical drainage or IR percutaneous drainage for pericardial effusion from 2010 to 2020. RESULTS: Among 447 patients, 243 were treated with surgical drainage, of which 27 (11%) developed PHI, compared with 7 of 204 patients (3%) who were treated with IR percutaneous drainage ( P =0.002); overall incidence of PHI decreased during the study period. Rates of reintervention (30-day: 1% vs 4%; 90-day: 4% vs 6%, P =0.7) and mortality (30-day: 21% vs 17%, P =0.3; 90-day: 39% vs 37%, P =0.7) were not different between patients treated with surgical drainage and IR percutaneous drainage. For both interventions, OS was shorter among patients with PHI than among patients without PHI (surgical drainage, median [95% confidence interval] OS, 0.89 mo [0.33-2.1] vs 6.5 mo [5.0-8.9], P <0.001; IR percutaneous drainage, 3.7 mo [0.23-6.8] vs 5.0 mo [4.0-8.1], P =0.044). CONCLUSIONS: With a coordinated multidisciplinary approach focusing on prompt clinical and echocardiographic evaluation, triage with bias toward IR percutaneous drainage than surgical drainage and postintervention intensive care resulted in lower incidence of PHI and improved outcomes.

Clinical outcomes of stereotactic body radiation therapy for malignant pleural mesothelioma.

BACKGROUND: The objective of this study is to determine the outcomes and toxicities of patients with malignant pleural mesothelioma (MPM) treated with stereotactic body radiotherapy (SBRT). MATERIALS AND METHODS: Data were extracted from an institutional tumor registry for patients diagnosed with mesothelioma and treated with SBRT. Kaplan-Meier and Cox regression analyses were employed to determine local control (LC) and overall survival (OS). RESULTS: Forty-four patients with 59 total treated tumors from December 2006 to April 2022 were identified. Fifty-one (86.4 %) cases had oligoprogressive disease (five sites or less). The median prescription dose delivered was 3000 cGy in 5 fractions (range: 2700-6000 cGy in 3-8 fractions). Fifty-one (86.4 %) tumors were in the pleura, 4 (6.8 %) spine, 2 (3.4 %) bone, 1 (1.7 %) brain, and 1 (1.7 %) pancreas. The median follow-up from SBRT completion for those alive at last follow-up was 28 months (range: 14-52 months). The most common toxicities were fatigue (50.8 %), nausea (22.0 %), pain flare (15.3 %), esophagitis (6.8 %), dermatitis (6.8 %), and pneumonitis (5.1 %). There were no grade ≥ 3 acute or late toxicities. There were 2 (3.4 %) local failures, one of the pleura and another of the spine. One-year LC was 92.9 % (95 % CI: 74.6-98.2 %) for all lesions and 96.3 % (95 % CI: 76.5-99.5 %) for pleural tumors. One-year LC was 90.9 % (95 % CI: 68.1-97.6 %) for epithelioid tumors and 92.1 % (95 % CI: 72.1-98.0 %) for oligoprogressive tumors. One-year OS from time of SBRT completion was 36.4 % (95 % CI: 22.6-50.3 %). On multivariable analysis, KPS was the lone significant predictor for OS (p = 0.029). CONCLUSIONS: Our single-institutional experience on patients with MPM suggests that SBRT is safe with a low toxicity profile and potentially achieve good local control.

Lung resection after initial nonoperative treatment for non-small cell lung cancer.

OBJECTIVES: The study objectives were to assess the outcomes of lung resection in patients with non-small cell lung cancer previously treated with nonoperative treatment and to identify prognostic factors associated with survival. METHODS: Patients who underwent surgery (2010-2022) after initial nonoperative treatment at a single institution were identified from a prospectively maintained database. Exclusion criteria included metachronous cancer, planned neoadjuvant therapy, and surgery for diagnostic or palliative indications. Cox models were constructed for overall survival and event-free survival. Survival of patients with stage IV disease was compared with survival of a nonstudy cohort who did not undergo surgery. RESULTS: In total, 120 patients met the inclusion criteria. Initial clinical stage was early stage in 16%, locoregionally advanced in 25%, and metastatic in 59% of patients. The indication for surgery was recurrence in 18%, local persistent disease in 23%, oligoprogression in 22%, and local control of oligometastatic disease in 38% of patients. Grade 3 or greater complications occurred in 5% of patients; 90-day mortality was 3%. Three-year event-free survival and overall survival were 39% and 73%, respectively. Male sex and lymphovascular invasion were associated with shorter event-free survival and overall survival; younger age and prior radiation therapy were associated with shorter overall survival. Patients with stage IV disease who received salvage lung resection had better overall survival than similar patients who received subsequent systemic therapy and no surgery. CONCLUSIONS: In this selected, heterogeneous population, lung resection after initial nonoperative treatment for non-small cell lung cancer was safe. Surgery as local consolidative therapy was associated with encouraging outcomes and should be considered for these patients.