The oncologic efficacy of extended thoracic resections.

Locally invasive lung cancers pose unique challenges for management. Surgical resection of these tumors can pose high morbidity due to the invasion into surrounding structures, including the spine, chest wall, and great vessels. With advances in immunotherapy and chemoradiation, the role for radical resection of these malignancies and associated oncologic outcomes is evolving. This article reviews the current literature of extended thoracic resections with a focus on technical approach, functional outcomes, and oncologic efficacy.

Performance of a new single-use bronchoscope versus a marketed single-use comparator: a bench study.

BACKGROUND: Single-use flexible bronchoscopes eliminate cross contamination from reusable bronchoscopes and are cost-effective in a number of clinical settings. The present bench study aimed to compare the performance of a new single-use bronchoscope (Boston Scientific EXALT Model B) to a marketed single-use comparator (Ambu aScope 4), each in slim, regular and large diameters. METHODS: Three bronchoscopy tasks were performed: water suction and visualization, "mucus" mass (synthetic mucoid mixture) suctioned in 30 s, and "mucus" plug (thicker mucoid mixture) suction. Suction ability, task completion times, and subjective ratings of visualization and overall performance on a scale of one to 10 (best) were compared. All bronchoscopy tasks were completed by 15 physicians representing diversity in specialization including pulmonary, interventional pulmonary, critical care, anesthesia, and thoracic surgery. Each physician utilized the six bronchoscope versions with block randomization by bronchoscope and task. RESULTS: Aspirated mean mass of "mucus" using EXALT Model B Regular was comparable to that for an aScope 4 Large (41.8 ± 8.3 g vs. 41.5 ± 5.7 g respectively, p = 0.914). In comparisons of scopes with the same outer diameter, the aspirated mean mass by weight of water and "mucus" was significantly greater for EXALT Model B than for aScope 4 (p < 0.001 for all three diameters). Mean ratings for visualization attributes were significantly better for EXALT Model B compared to aScope 4 (p-value range 0.001-0.029). CONCLUSION: A new single-use bronchoscope provided strong suction capability and visualization compared to same-diameter marketed single-use comparators in a bench model simulation.

The Society of Thoracic Surgeons General Thoracic Surgery Database: 2023 Update on Outcomes and Research.

The Society of Thoracic Surgeons General Thoracic Surgery Database (GTSD) continues its trajectory of growth and enhancement, solidifying its stature as a premier global thoracic surgical database. The past year witnessed a notable expansion with the inclusion of 10 additional participating sites, now totaling 287, augmenting the database's repository to more than 800,000 procedures. A significant stride was made in refining the data audit process, thereby elevating the accuracy and completeness metrics, a testament to the relentless pursuit of data integrity. The GTSD further broadened its research apparatus, with 15 scholarly publications, a 50% uptick from the preceding year. These publications underscore the database's instrumental role in advancing thoracic surgical knowledge. In a concerted effort to alleviate data entry exigencies, the GTSD Task Force also instituted streamlined data submission protocols, a move lauded by participant sites. This report delineates the recent advancements, volume trajectories, and outcome metrics and encapsulates the prolific research output emanating from the GTSD, reflecting a year of substantial progress and academic fecundity.

Trends and Comparative Outcomes Between Operative Approaches for Segmentectomy in Lung Cancer.

BACKGROUND: Segmentectomy is increasingly performed for non-small cell lung cancer (NSCLC). However, comparative outcomes data between open, robotic-assisted (RATS) and video-assisted thoracoscopic (VATS) approaches are limited. METHODS: A retrospective cohort study of NSCLC segmentectomy cases (2013-2021) from the Society of Thoracic Surgeons General Thoracic Surgery Database was performed. Baseline characteristics were balanced using inverse probability of treatment weighting and compared by operative approach. Volume trends, outcomes, and nodal upstaging were assessed. RESULTS: Of 9,927 segmentectomy patients, 84.8% underwent minimally invasive surgery (MIS), with RATS becoming the most common approach in 2019. Open segmentectomy is more likely performed at low-volume centers (p<0.0001), whereas RATS more likely high-volume centers (p<0.0001). VATS had higher open conversion rate than RATS (OR 11.8, CI [7.01-21.6], p<0.001). MIS had less 30-day morbidity compared to open segmentectomy (VATS OR 0.71 95% CI [0.55-0.94], p=0.013; RATS OR 0.59, CI [0.43-0.81], p=0.001). Number of nodes and stations harvested were highest for RATS, however N1 upstaging was more likely in open compared to RATS (OR 0.63, CI 0.45-0.89, p< 0.007) and VATS (OR 0.61, CI 0.46-0.83, p=0.001). CONCLUSIONS: Segmentectomy volume has increased considerably with RATS becoming the most common approach. MIS has less major morbidity compared to open segmentectomy with no difference between VATS and RATS. However, risk of open conversion is higher with VATS. RATS had increased nodal harvest whereas hilar nodal upstaging was highest with thoracotomy. This study reveals significant differences in outcomes exist between segmentectomy operative approach; the impact of approach on survival merits further investigation.

Advanced Endoscopy for Thoracic Surgeons.

The thoracic surgeon, well versed in advanced endoscopy, has an array of therapeutic options for foregut pathologic conditions. Peroral endoscopic myotomy (POEM) offers a less-invasive means to treat achalasia, and the authors' preferred approach is described in this article. They also describe variations of POEM, such as G-POEM, Z-POEM, and D-POEM. In addition, endoscopic stenting, endoluminal vacuum therapy, endoscopic internal drainage, and endoscopic suturing/clipping are discussed and can be valuable tools for esophageal leaks and perforations. Endoscopic procedures are advancing rapidly, and thoracic surgeons must maintain at the forefront of these technologies.

The Society of Thoracic Surgeons General Thoracic Surgery Database: 2022 Update on Outcomes and Research.

The Society of Thoracic Surgeons General Thoracic Surgery Database (STS GTSD) remains the largest and most robust thoracic surgical database in the world. Participating sites receive risk-adjusted performance reports for benchmarking and quality improvement initiatives. The GTSD also provides several mechanisms for high-quality clinical research using data from 274 participant sites and 781,000 procedures since its inception in 2002. Participant sites are audited at random annually for completeness and accuracy. Over the last year and a half, the GTSD Task Force continued to refine the data collection process, implementing an updated data collection form in July 2021, ensuring high data fidelity while minimizing data entry burden. In addition, the STS Workforce on National Databases has supported a robust GTSD-based research program, which led to eight scholarly publications in 2021. This report provides an update on volume trends, outcomes, and database initiatives as well as a summary of research productivity resulting from the GTSD over the preceding year.

Vascular Invasion Predicts Recurrence in Stage IA2-IB Lung Adenocarcinoma but not Squamous Cell Carcinoma.

BACKGROUND: Lymphovascular invasion (LVI) is an adverse prognostic feature in resected stage I non-small cell lung cancer (NSCLC); however, it is unclear if the prognostic significance applies to both lung adenocarcinoma (LUAD) and squamous cell carcinoma (LUSC). MATERIALS AND METHODS: A retrospective review of H&E-stained slides from surgically resected AJCC 8th ed. stage IA2-IB LUAD (n = 344) and LUSC (n = 102) from two institutions was performed. LVI was defined as either lymphatic (LI) or vascular (VI) invasion. Outcomes were assessed by 5-year recurrence-free survival (RFS) estimates using the Kaplan-Meier method. RESULTS: The cohorts of LUAD and LUSC showed no significant differences in 5-year RFS (81% each), stage, age, race, or surgical procedure. The presence of LVI, VI, and LI was predictive of 5-year RFS for LUAD (LVI + 71% vs. LVI - 92%, P < 0.001; VI + 64% vs. VI - 90%, P < 0.001; LI + 75% vs. LI - 84%, P = 0.030) but not LUSC (LVI + 84% vs. LVI - 79%, P = 0.740; VI + 83% vs. VI- 80%, P = 0.852; LI + 84% vs. LI - 81%, P = 0.757). Among LUAD with LVI, VI was a stronger predictor of 5-year RFS than the remaining subset of VI-LI + tumors (64% vs. 87%, P = 004). Subset analysis of LI among LUAD stratified by VI showed no significant prognostic advantage to adding LI for risk stratification (VI-LI + 87% vs. VI-LI - 92%, P = 0.347 & VI+LI + 62% vs. VI + LI- 66%, P = 0.422). VI was present in 36% of LUAD. CONCLUSION: Vascular invasion is a strong predictor of recurrence in stage IA2-IB LUAD but not in LUSC. Adjuvant therapy trials should be directed at this subgroup.

Vascular invasion predicts the subgroup of lung adenocarcinomas ≤2.0 cm at risk of poor outcome treated by wedge resection compared to lobectomy.

Background: Recent randomized control trials (JCOG0802 and CALGB140503) have shown sublobar resection to be noninferior to lobectomy for non-small cell lung cancer (NSCLC) ≤2.0 cm. We have previously proposed histologic criteria stratifying lung adenocarcinoma into indolent low malignant potential (LMP) and aggressive angioinvasive adenocarcinomas, resulting in better prognostication than provided by World Health Organization grade. Here we determine whether pathologic classification is reproducible and whether subsets of adenocarcinomas predict worse outcomes when treated by wedge resection compared to lobectomy. Methods: A retrospective cohort of 108 recipients of wedge resection and 187 recipients of lobectomy for stage I/0 lung adenocarcinomas ≤2.0 cm was assembled from 2 institutions. All tumors were classified by a single pathologist, and interobserver reproducibility was assessed in a subset (n = 92) by 5 pathologists. Results: Angioinvasive adenocarcinoma (21%-27% of cases) was associated with worse outcomes when treated with wedge resection compared to lobectomy (5-year recurrence-free survival, 57% vs 85% [P = .007]; 5-year disease-free survival [DSS], 70% vs 90% [P = .043]; 7-year overall survival, 37% vs 58% [P = .143]). Adenocarcinoma in situ (AIS), minimally invasive adenocarcinoma (MIA), and LMP exhibited 100% 5-year DSS regardless of the surgical approach. Multivariable analysis showed that angioinvasion, tumor size, margin status, and extent of nodal sampling were significantly associated with recurrence but not with surgical procedure. There was substantial interobserver reproducibility among the pathologists for the diagnosis of angioinvasive adenocarcinoma (κ = 0.71) and the combined indolent AIS/MIA/LMP group (κ = 0.74). Conclusions: The majority (∼75%) of lung adenocarcinomas ≤2 cm are adequately managed with wedge resection; however, angioinvasive adenocarcinomas (∼25%) treated by wedge resection with suboptimal nodal sampling exhibit poor outcomes, with a 40% to 45% rate of recurrence within 5 years and 60% to 65% overall mortality at 7 years.

Pathologic response to preoperative chemotherapy in colorectal liver metastases: fibrosis, not necrosis, predicts outcome.

BACKGROUND: Pathologic response to preoperative chemotherapy for colorectal liver metastases (CLM) is associated with survival after hepatectomy. Histologically, dominant response patterns include fibrosis, necrosis and/or acellular mucin, but some of these changes can appear without previous chemotherapy and their individual correlation with outcome is unknown. METHODS: Pathology slides from patients who underwent CLM resection (irrespective of preoperative chemotherapy status) were rereviewed by a blinded pathologist. Pathologic response was recorded as the summation of percentage necrosis, fibrosis and acellular mucin. Associations between pathologic response, its components, preoperative chemotherapy, and survival were analyzed. RESULTS: Pathology slides were rereviewed in 366 patients undergoing CLM resection from 2003 to 2007. Preoperative chemotherapy was administered in 249 (68 %) patients, who, when compared to no preoperative chemotherapy patients, had higher rates of overall pathologic response (57 vs. 46 %, P < .01), fibrosis (21 vs. 12 %, P < .01) and acellular mucin (6 vs. 3 %, P = .05) but similar rates of necrosis (30 vs. 31 %, P = .30). In patients receiving preoperative chemotherapy, overall pathologic response ≥ 75 % (5 year, 83 vs. 47 %, P < .01) and fibrosis ≥ 40 % (5 year, 87 vs. 51 %, P < .01) independently correlated with disease-specific survival after hepatectomy. Preoperative hepatic artery infusion chemotherapy (P = .04) and bevacizumab (P = .05) were marginally associated with overall pathologic response and fibrosis, respectively. CONCLUSIONS: Fibrosis is the predominant chemotherapy-related pathologic alteration driving the association of treatment response with survival after CLM resection. Necrosis in CLM is not related to chemotherapy or outcome.

Surgeon Experience Is Associated With Prolonged Air Leak After Robotic-assisted Pulmonary Lobectomy.

BACKGROUND: Prolonged air leak (PAL) (>5 days) after robotic-assisted pulmonary lobectomy is a significant complication. This study aimed to determine patient- and surgeon-related factors that can predict PAL after robotic lobectomy for lung cancer. METHODS: This study was a retrospective review of a single-center experience of robotic-assisted lobectomy for lung cancer. Perioperative variables, including surgeon case experience, patient demographics, diffusion capacity of lung for carbon monoxide, forced expiratory volume in 1 second, body mass index, and smoking status were evaluated. RESULTS: A total of 305 robotic-assisted lobectomies performed by 4 surgeons met inclusion criteria from June 2016 to February 2019. The 30-day postoperative mortality was 1.2%. PAL developed in 27 of 305 (8.8%) patients. Surgeons' robotic experience was grouped by 10-case increments. When adjusted for age and sex, the odds for PAL decreased by 15% for every 10 robotic lobectomies the surgeons performed (odds ratio [OR], 0.85; 95% CI, 0.74-0.99; P = .0384). Logistic regression models showed a linear transition curve at the 50th case. Female sex (OR, 2.62; 95% CI, 1.03-6.69; P = .0314) and younger age (OR, 0.61; 95% CI, 0.41-0.91; P = .0184) were statistically significant risk factors for PAL. Cumulative sum analysis similarly showed a strong association between experience and PAL. Preoperative diffusing capacity of lung for carbon monoxide, forced expiratory volume in 1 second, body mass index, and smoking status were not statistically significant predictive factors. CONCLUSIONS: These results show that surgeon robotic case experience is associated with the rate of postoperative PAL: as the number of robotic lobectomies increases, the rate of PAL significantly decreases. It is imperative to emphasize that a learning curve exists for this approach that directly affects patient outcomes.

Impact of Chest Wall Resection on Mortality After Lung Resection for Non-Small Cell Lung Cancer.

BACKGROUND: Lung cancer invading the chest wall is treated with concomitant en bloc lung and chest wall resection (CWR). It is unclear how CWR affects postoperative outcomes of lung resection. We hypothesized that CWR would be associated with increased risk of adverse outcomes after lung cancer resection. METHODS: We performed a retrospective analysis of The Society of Thoracic Surgeons (STS) General Thoracic Surgery Database from 2016-2019. Patients with superior sulcus tumors were excluded. Patient demographic and operative outcomes were compared between those with and without CWR. Chest wall resection was added to existing STS lung risk models to determine the association with a composite adverse outcome, which included major morbidity and death. RESULTS: Among 41 310 lung resections, 306 (0.74%) occurred with concomitant CWR. Differences between those with and without CWR included demographic and comorbidities. Patients undergoing CWR were more likely to have the composite adverse outcome (64 of 306 [20.9%] vs 3128 of 41 004 [7.6%] for non-CWR resections, P < .001). Mortality was also increased among the CWR cohort (2.9% vs 1.1%, P = .003). CWR was associated with an increased risk of adverse composite outcome among all lung resection patients in a multivariable model (odds ratio 1.74, P = .0003) and the lobectomy subgroup (odds ratio 2.35, P < .0001). Among institutions with ≥10 lung resections, 49.1% performed lung resections with CWR. CONCLUSIONS: Concomitant CWR adds risk of adverse outcomes after lung cancer resection. As a subset of intuitions perform CWR, quality assessments should control for CWR. This variable will be incorporated into the STS lung cancer and lobectomy quality composite measures.

Conversion to Thoracotomy During Thoracoscopic vs Robotic Lobectomy: Predictors and Outcomes.

BACKGROUND: Conversion to thoracotomy during minimally invasive lobectomy for lung cancer is occasionally necessary. Differences between video-assisted thoracoscopic surgery (VATS) and robotic-assisted thoracoscopic surgery (RATS) lobectomy conversion have not been described. METHODS: We queried The Society of Thoracic Surgeons General Thoracic Surgery Database from January 1, 2015 to December 31, 2018. Patients with prior thoracic operations and metastatic disease were excluded. Univariable comparisons with χ2 and Kruskal-Wallis tests and multivariable logistic regression modeling were performed. RESULTS: There were 27,695 minimally invasive lobectomies from 269 centers. Conversion to thoracotomy occurred in 11.0% of VATS and 6.0% of RATS (P < .001). Conversion was associated with increased mortality (P < .001), major complications (P < .001), and intraoperative (P < .001) and postoperative (P < .001) blood transfusions. Conversion from RATS occurred emergently (P < .001) and for vascular injury (P < .001) more frequently than from VATS, but there was no difference in overall major complications or mortality. Mortality after conversion was 3.1% for RATS and 2.2% for VATS (P = .24). Clinical cancer stage II or III (P < .001), preoperative chemotherapy (P = .003), forced expiratory volume in 1 second (P = .006), body mass index (P < .001), and left-sided resection (P = .0002) independently predicted VATS conversion. For RATS clinical stage III (P = .037), left-sided resection (P = .041), and forced expiratory volume in 1 second (P = .002) predicted conversion. Lower volume centers had increased rates of conversion (P < .001) in both groups. CONCLUSIONS: Conversion from minimally invasive to open lobectomy is associated with increased morbidity and mortality. Conversion occurs more frequently during VATS compared with RATS, albeit less often emergently, and with similar rates of overall mortality and major complications. Predictors, urgency, and reasons for conversion differ between RATS and VATS lobectomy and may assist in patient selection.

Vascular invasion identifies the most aggressive histologic subset of stage I lung adenocarcinoma: Implications for adjuvant therapy.

OBJECTIVES: Approximately 15% of stage I lung adenocarcinomas will recur despite adequate surgical therapy. Adjuvant therapy may benefit specific high-risk subsets; however, it is unclear which patients are sufficiently predisposed to recurrence to warrant intensified therapy. MATERIALS AND METHODS: 517 AJCC 8th edition stage I/0 lung adenocarcinomas ≤ 4 cm total size were graded (WHO-2015 and WHO-2021) and compared to stage subgroupings using 7-year recurrence free (RFS), disease specific (DSS), and overall survival (OS). Low malignant potential (LMP) adenocarcinoma was assigned as previously defined. Univariate/multivariate analysis was performed to assess risk factors associated with aggressive behavior. RESULTS: Vascular invasion was the most significant histologic feature on multivariate analysis for both RFS (HR = 4.68, p < 0.001) and DSS (HR = 3.67, p = 0.001) and nearly reached significance for OS (HR = 1.47, p = 0.060). Angioinvasive adenocarcinomas comprised 26 % of the cohort and exhibited a 7-year 64 % RFS, 73 % DSS, and 50 % OS; in contrast to 20 % WHO-2015-G3 (7-year 71 % RFS, 79 % DSS, & 54 % OS), 44 % WHO-2021-G3 (7-year 79 % RFS, 85 % DSS, & 56 % OS), and 21 % stage IB (7-year 72 % RFS, 79 % DSS, and 50 % OS) adenocarcinomas. The majority (>50 %) of overall mortality was disease specific for angioinvasive adenocarcinoma whereas ≤25 % of overall mortality was disease specific for the remaining tumors. Angioinvasive adenocarcinomas were proportionally more common among those still smoking at diagnosis (49 %), male sex (49 %), and black race (16 %) than other subtypes. CONCLUSION: Patients with AJCC 8th ed. stage I angioinvasive lung adenocarcinomas are at high-risk of cancer-specific mortality and should be considered for clinical trials evaluating benefit of adjuvant therapy.

Real-time intraoperative detection of tissue hypoxia in gastrointestinal surgery by wireless pulse oximetry.

OBJECTIVE: Dehiscence or leakage after bowel anastomoses is associated with high morbidity and mortality. Perfusion and local tissue oxygenation (StO2), independent of systemic oxygen saturation, are fundamental determinants of anastomotic viability. Because current technology is limited for monitoring local StO2 at bowel anastomoses, our goal was to construct a wireless pulse oximeter (WiPOX) to monitor real-time intraoperative tissue oxygenation, permitting identification of compromised anastomotic perfusion. METHODS: We have: (a) designed a handheld device capable of real-time monitoring of serosal and mucosal StO2 through endoscopic ports with wireless data transmission to standard intraoperative monitors, (b) constructed the WiPOX using materials meeting FDA regulations for intraoperative use and reuse, (c) performed accuracy testing in humans by comparing the WiPOX to standard pulse oximeters, and (d) tested WiPOX efficacy for detecting early tissue hypoxia in stomach, intestines, and kidneys in anesthetized rats and swine. RESULTS: In humans, WiPOX demonstrated accuracy within 3% compared with commercially available pulse oximeters. Application of the WiPOX in rats and swine demonstrated normal serosal and mucosal StO2 and pulse rates in healthy small bowel and stomach. Within 30 s of compromised perfusion, the WiPOX detected bowel hypoxia over a wide range of oxygen saturation (p<0.005). A greater degree of hypoxia was detected in mucosal versus serosal measurements during early ischemia, despite normal appearance of tissue. The onboard sensor-processor unit permitted noninvasive pulse oximetry and integration with current intraoperative monitoring. The contact pressure-sensing head allowed for consistent, high-quality StO2 waveform readouts despite the presence of body fluids. CONCLUSIONS: We have constructed, validated, and successfully tested a novel wireless pulse oximeter capable of detecting intraoperative tissue hypoxia in open or endoscopic surgery. This device will aid surgeons in detecting anastomotic vascular compromise and facilitate choosing an ideal site for bowel anastomosis by targeting well-perfused tissue with optimal healing capacity.

Robotic-Assisted Complex Pulmonary Resection: Sleeve Lobectomy for Cancer.

The use of robotic assistance for complex pulmonary resections such as segmentectomy and sleeve lobectomy has steadily increased in recent years. These operations are technically challenging as they require fine dissection and suturing, which is often difficult to perform using traditional minimally invasive techniques. Robotic surgery is well-suited for complex pulmonary surgery given its specific advantages related to superior optics and precise tissue manipulation and dissection. Herein we describe our technique for robotic-assisted complex pulmonary surgery with a specific focus on right upper sleeve lobectomy for cancer, including associated video case demonstration. The principles discussed are generalizable to other complex lung and tracheobronchial operations and highlight the benefits of the robotic platform.

Surgery and invasive diagnostic procedures for benign disease are rare in a large low-dose computed tomography lung cancer screening program.

OBJECTIVE: Lung cancer screening with low-dose chest computed tomography improves survival. However, concerns about overdiagnosis and unnecessary interventions persist. We reviewed our lung cancer screening program to determine the rate of surgery and invasive procedures for nonmalignant disease. METHODS: We reviewed all patients undergoing lung cancer screening from January 2012 to June 2017 with follow-up through January 2019. Patients with suspicious findings (Lung CT Screening Reporting and Data System 4) were referred for further evaluation. RESULTS: Of 3280 patients screened, 345 (10.5%) had Lung CT Screening Reporting and Data System 4 findings. A total of 311 patients had complete follow-up, of whom 93 (29.9%) were diagnosed with lung cancer. Eighty-three patients underwent lung surgery (2.5% of screened patients). Forty patients underwent lobectomy (48.2%), 3 patients (3.6%) underwent bilobectomy, and 40 patients (48.2%) underwent sublobar resection. Fourteen patients underwent surgery for benign disease (0.43% of screened patients). Fifty-four patients, 5 with benign disease, had at least 1 invasive diagnostic procedure but never underwent surgery. The incidence of any invasive intervention for nonmalignant disease was 0.95% (31/3280 patients). There were no postprocedural deaths within 60 days. Twenty-five patients (0.76%) underwent stereotactic body radiation therapy; 19 patients (76%) had presumed lung cancer without pretreatment pathologic confirmation. CONCLUSIONS: Surgical resection for benign disease occurred in 0.43% of patients undergoing lung cancer screening. The combined incidence of any invasive diagnostic or therapeutic intervention, including surgical resection, for benign disease was only 0.95%. Periprocedural complications were rare. These results indicate that concern over unnecessary interventions is overstated and should not hinder adoption of lung cancer screening. A multidisciplinary team approach, including thoracic surgeons, is critical to maintain an appropriate rate of interventions in lung cancer screening.

The Society of Thoracic Surgeons General Thoracic Surgery Database: 2021 Update on Outcomes and Research.

The Society of Thoracic Surgeons General Thoracic Surgery Database (STS GTSD) remains the largest and most robust thoracic surgical database in the world. Participating sites receive risk-adjusted performance reports for benchmarking and quality improvement initiatives. The GTSD also provides several mechanisms for high-quality clinical research using data from 271 participant sites and nearly 720,000 procedures since its inception in 2002. Participant sites are audited at random annually for completeness and accuracy. During the last year and a half, the GTSD Task Force continued to refine the data collection form, ensuring high-quality data while minimizing data entry burden. In addition, the STS Workforce on National Databases has supported robust GTSD-based research program, which led to 10 scholarly publications in 2020. This report provides an update on outcomes, volume trends, and database improvements as well as a summary of research productivity resulting from the GTSD over the preceding year.

Pulmonary Adenocarcinomas of Low Malignant Potential: Proposed Criteria to Expand the Spectrum Beyond Adenocarcinoma In Situ and Minimally Invasive Adenocarcinoma.

Lung cancer screening has improved mortality among high-risk smokers but has coincidentally detected a fraction of nonprogressive adenocarcinoma historically classified as bronchoalveolar carcinoma (BAC). In the National Lung Screening Trial (NLST) the majority of BAC-comprising 29% of computed tomography-detected stage I lung adenocarcinoma-were considered overdiagnosis after extended follow-up comparison with the control arm. In the current classification, adenocarcinoma in situ and minimally invasive adenocarcinoma have replaced BAC but together comprise only ∼5% of stage I lung adenocarcinoma. Lepidic and subsets of papillary and acinar adenocarcinoma also infrequently recur. We, therefore, propose criteria for low malignant potential (LMP) adenocarcinoma among nonmucinous adenocarcinoma measuring ≤3 cm in total, exhibiting ≥15% lepidic growth, and lacking nonpredominant high-grade patterns (≥10% cribriform, ≥5% micropapillary, ≥5% solid), >1 mitosis per 2 mm2, angiolymphatic or visceral pleural invasion, spread through air spaces or necrosis. We tested these criteria in a multi-institutional cohort of 328 invasive stage I (eighth edition) and in situ adenocarcinomas and observed 16% LMP and 7% adenocarcinoma in situ/minimally invasive adenocarcinoma which together (23%) approximated the frequency of overdiagnosed stage I BAC in the NLST. The LMP group had 100% disease-specific survival. The proposed LMP criteria, incorporating multiple histologic parameters, may be a clinically useful "low-grade" prognostic group. Validation of these criteria in additional retrospective cohorts and prospective screen-detected cohorts should be considered.