Exposure to Agent Orange is associated with increased recurrence after surgical treatment of stage I non-small cell lung cancer

OBJECTIVE

Approximately 3 million Americans served in the armed forces during the Vietnam War. Veterans have a higher incidence rate of lung cancer compared with the general population, which may be related to exposures sustained during service. Agent Orange, one of the tactical herbicides used by the armed forces as a means of destroying crops and clearing vegetation, has been linked to the development of several cancers including non-small cell lung cancer. However, traditional risk models of lung cancer survival and recurrence often do not include such exposures. We aimed to examine the relationship between Agent Orange exposure and overall survival and disease recurrence for surgically treated stage I non-small cell lung cancer.

METHODS

We performed a retrospective cohort study using a uniquely compiled dataset of US Veterans with pathologic I non-small cell lung cancer. We included adult patients who served in the Vietnam War and underwent surgical resection between 2010 and 2016. Our 2 comparison groups included those with identified Agent Orange exposure and those who were unexposed. We used multivariable Cox proportional hazards and Fine and Gray competing risk analyses to examine overall survival and disease recurrence for patients with pathologic stage I disease, respectively.

RESULTS

A total of 3958 Vietnam Veterans with pathologic stage I disease were identified (994 who had Agent Orange exposure and 2964 who were unexposed). Those who had Agent Orange exposure were more likely to be male, to be White, and to live a further distance from their treatment facility (P < .05). Tumor size distribution, grade, and histology were similar between cohorts. Multivariable Cox proportional hazards modeling identified similar overall survival between cohorts (Agent Orange exposure hazard ratio, 0.97; 95% CI, 0.86-1.09). Patients who had Agent Orange exposure had a 19% increased risk of disease recurrence (hazard ratio, 1.19; 95% CI, 1.02-1.40).

CONCLUSIONS

Veterans with known Agent Orange exposure who undergo surgical treatment for stage I non-small cell lung cancer have an approximately 20% increased risk of disease recurrence compared with their nonexposed counterparts. Agent Orange exposure should be taken into consideration when determining treatment and surveillance regimens for Veteran patients.

Lobe-specific lymph node sampling is associated with lower risk of cancer recurrence

Objective

Adequate intraoperative lymph node (LN) assessment is a critical component of early-stage non-small cell lung cancer (NSCLC) resection. The National Comprehensive Cancer Network and the American College of Surgeons Commission on Cancer (CoC) recommend station-based sampling minimums agnostic to tumor location. Other institutions advocate for lobe-specific LN sampling strategies that consider the anatomic likelihood of LN metastases. We examined the relationship between lobe-specific LN assessment and long-term outcomes using a robust, highly curated cohort of stage I NSCLC patients.

Methods

We performed a cohort study using a uniquely compiled dataset from the Veterans Health Administration and manually abstracted data from operative and pathology reports for patients with clinical stage I NSCLC (2006-2016). For simplicity in comparison, we included patients who had right upper lobe (RUL) or left upper lobe (LUL) tumors. Based on modified European Society of Thoracic Surgeons guidelines, lobe-specific sampling was defined for RUL tumors (stations 2, 4, 7, and 10 or 11) and LUL tumors (stations 5 or 6, 7, and 10 or 11). Our primary outcome was the risk of cancer recurrence, as assessed by Fine and Gray competing risks modeling. Secondary outcomes included overall survival (OS) and pathologic upstaging. Analyses were adjusted for relevant patient, disease, and treatment variables.

Results

Our study included 3534 patients with RUL tumors and 2667 patients with LUL tumors. Of these, 277 patients (7.8%) with RUL tumors and 621 patients (23.2%) with LUL tumors met lobe-specific assessment criteria. Comparatively, 34.7% of patients met the criteria for count-based assessment, and 25.8% met the criteria for station-based sampling (ie, any 3 N2 stations and 1 N1 station). Adherence to lobe-specific assessment was associated with lower cumulative incidence of recurrence (adjusted hazard ratio [aHR], 0.83; 95% confidence interval [CI], 0.70-0.98) and a higher likelihood of pathologic upstaging (aHR, 1.49; 95% CI, 1.20-1.86). Lobe-specific assessment was not associated with OS.

Conclusions

Adherence to intraoperative LN sampling guidelines is low. Lobe-specific assessment is associated with superior outcomes in early-stage NSCLC. Quality metrics that assess adherence to intraoperative LN sampling, such as the CoC Operative Standards manual, also should consider lobe-specific criteria.

Inhaled medications for chronic obstructive pulmonary disease predict surgical complications and survival in stage I non-small cell lung cancer

Background

Lung function is routinely assessed prior to surgical resection for non-small cell lung cancer (NSCLC). Further assessment of chronic obstructive pulmonary disease (COPD) using inhaled COPD medications to determine disease severity, a readily available metric of disease burden, may predict postoperative outcomes and overall survival (OS) in lung cancer patients undergoing surgery.

Methods

We retrospectively evaluated clinical stage I NSCLC patients receiving surgical treatment within the Veterans Health Administration from 2006-2016 to determine the relationship between number and type of inhaled COPD medications (short- and long-acting beta2-agonists, muscarinic antagonists, or corticosteroids prescribed within 1 year before surgery) and postoperative outcomes including OS using multivariable models. We also assessed the relationship between inhaled COPD medications, disease severity [measured by forced expiratory volume in 1 second (FEV1)], and diagnosis of COPD.

Results

Among 9,741 veterans undergoing surgery for clinical stage I NSCLC, patients with COPD were more likely to be prescribed inhaled medications than those without COPD [odds ratio (OR) =5.367, 95% confidence interval (CI): 4.886-5.896]. Increased severity of COPD was associated with increased number of prescribed inhaled COPD medications (P<0.0001). The number of inhaled COPD medications was associated with prolonged hospital stay [adjusted OR (aOR) =1.119, 95% CI: 1.076-1.165), more major complications (aOR =1.117, 95% CI: 1.074-1.163), increased 90-day mortality (aOR =1.088, 95% CI: 1.013-1.170), and decreased OS [adjusted hazard ratio (aHR) =1.061, 95% CI: 1.042-1.080]. In patients with FEV1 ≥80% predicted, greater number of prescribed inhaled COPD medications was associated with increased 30-day mortality (aOR =1.265, 95% CI: 1.062-1.505), prolonged hospital stay (aOR =1.130, 95% CI: 1.051-1.216), more major complications (aOR =1.147, 95% CI: 1.064-1.235), and decreased OS (aHR =1.058, 95% CI: 1.022-1.095). When adjusting for other drug classes and covariables, short-acting beta2-agonists were associated with increased 90-day mortality (aOR =1.527, 95% CI: 1.120-2.083) and decreased OS (aHR =1.087, 95% CI: 1.005-1.177).

Conclusions

In patients with early-stage NSCLC, inhaled COPD medications prescribed prior to surgery were associated with both short- and long-term outcomes, including in patients with FEV1 ≥80% predicted. Routine assessment of COPD medications may be a simple method to quantify operative risk in early-stage NSCLC patients.

Development and Validation of the VA Lung Cancer Mortality (VALCAN-M) Score for 90-Day Mortality Following Surgical Treatment of Clinical Stage I Lung Cancer

OBJECTIVE

The aim was to develop and validate the Veterans Administration (VA) Lung Cancer Mortality (VALCAN-M) score, a risk prediction model for 90-day mortality following surgical treatment of clinical stage I nonsmall-cell lung cancer (NSCLC).

BACKGROUND

While surgery remains the preferred treatment for functionally fit patients with early-stage NSCLC, less invasive, nonsurgical treatments have emerged for high-risk patients. Accurate risk prediction models for postoperative mortality may aid surgeons and other providers in optimizing patient-centered treatment plans.

METHODS

We performed a retrospective cohort study using a uniquely compiled VA data set including all Veterans with clinical stage I NSCLC undergoing surgical treatment between 2006 and 2016. Patients were randomly split into derivation and validation cohorts. We derived the VALCAN-M score based on multivariable logistic regression modeling of patient and treatment variables and 90-day mortality.

RESULTS

A total of 9749 patients were included (derivation cohort: n=6825, 70.0%; validation cohort: n=2924, 30.0%). The 90-day mortality rate was 4.0% (n=390). The final multivariable model included 11 factors that were associated with 90-day mortality: age, body mass index, history of heart failure, forced expiratory volume (% predicted), history of peripheral vascular disease, functional status, delayed surgery, American Society of Anesthesiology performance status, tumor histology, extent of resection (lobectomy, wedge, segmentectomy, or pneumonectomy), and surgical approach (minimally invasive or open). The c statistic was 0.739 (95% CI=0.708-0.771) in the derivation cohort.

CONCLUSIONS

The VALCAN-M score uses readily available treatment-related variables to reliably predict 90-day operative mortality. This score can aid surgeons and other providers in objectively discussing operative risk among high-risk patients with clinical stage I NSCLC considering surgery versus other definitive therapies.

Abstract 6741: Number of prescription drugs and overall survival in metastatic castrate resistant prostate cancer

Background: Assessment of comorbid diseases is essential to clinical research and may risk-stratify patients for adverse events and death. Total number of prescription medications and drug classes could be an easy-to-use tool for estimating patient risk independent of established methods such as the Charlson Comorbidity Index (CCI) that is created from administrative data. Additionally, clinicians have access to prescription medication lists, facilitating assessment of comorbidities in clinical settings.

Methods: Retrospective observational study of US Veterans treated for metastatic castrate resistant prostate cancer in the Veterans Health Administration who received treatment with abiraterone or enzalutamide between May 2011-June 2, 2017. We determined number of unique drugs and anatomic therapeutic chemical (ATC) drug classes prescribed in the year prior up to 14 days before initiation of treatment. Multivariable logistic regression and Cox proportional hazard modeling was used to assess the association between number of drugs with all-cause 90-day mortality and overall survival (OS) while accounting for important covariates including age, CCI, body-mass index, prostate specific antigen, race, prior docetaxel, hemoglobin, albumin, bilirubin, and creatinine.

Results: Among 11,021 Veterans, a median (IQR) of 11 (6,18) unique medications and 10 (5,15) unique ATC medication classes were filled in the year prior to treatment. The median age was 75 years with median CCI of 3 and 2,550 were black (23.1%). Increasing age was associated with increased CCI across age strata with mean CCI of 3.7 in age &lt;70, 4.2 in age 70-79, and 4.3 in age 80+ (p&lt;0.001). Increased age was associated with decreased number of unique medicines with mean 14.7 in age &lt;70, 12.7 in age 70-79, and 11.2 in age 80+ (p&lt;0.001). Black race was associated with increased mean number of medications compared to white race (15.5 vs. 12.0, p&lt;0.001). After adjusting for relevant patient, tumor, and treatment factors, the number of medications and drug classes were each independently associated with increased 90-day mortality with adjusted OR (95% CI) of 1.021 (1.011,1.030) and 1.024 (1.012,1.036) respectively. Both number of medications and number of classes were also associated with decreased OS with adjusted Hazard Ratio of 1.015 (1.013,1.018) and 1.018 (1.014,1.021) respectively. Within subgroups of patients with comparable CCI, increased number of medications was associated with increased risk of death.

Conclusion: The number of prescription medications and drug classes are independently associated with short- and long-term outcomes in patients undergoing treatment for metastatic castrate resistant prostate cancer, even after accounting for important covariates including age and CCI. Assessment of patient medications may provide a simple, yet reliable tool to assess comorbidities, risk of adverse events, and death.

Citation Format: Martin W. Schoen, Carley Pickett, Daniel B. Eaton, Brendan T. Heiden, Su-Hsin Chang, Yan Yan, Melanie P. Subramanian, Varun Puri. Number of prescription drugs and overall survival in metastatic castrate resistant prostate cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 6741.

Abstract 734: Comprehensive validation of high-risk clinicopathologic features in early-stage, node-negative non-small cell lung cancer

Objective: Current guidelines recommend adjuvant therapy for patients with completely resected non-small cell lung cancer (NSCLC) with high-risk clinical or pathologic features. Despite this, the relationship between these features and cancer recurrence is poorly elucidated.

Methods: We conducted a retrospective cohort study using a uniquely compiled dataset from the US Veterans Health Administration (VHA) including all Veterans with pathologic early-stage (≤5cm, N0) NSCLC receiving definitive surgical treatment (2010-2016). Based on National Comprehensive Cancer Network guidelines, we evaluated 6 high-risk features: tumor size, tumor grade, visceral-pleural invasion, lymphovascular invasion, non-anatomic wedge resection, and adequacy of nodal sampling. We developed a score reflecting the relationship between these high-risk features and recurrence, using a multivariable competing risk model (death as competing event). The score performance was then tested in an external cohort from the National Cancer Database (NCDB).

Results: The study included 3,799 Veterans. The median follow-up was 7.1 years. Recurrence was detected in 800 (21.1%) patients. The association between high-risk features and cancer recurrence were as follows: tumor size (e.g., 31-40mm vs. 0-10mm, multivariable-adjusted hazard ratio, aHR 1.676, 95% CI 1.229-2.285, p=0.001), tumor grade (e.g., III vs. I, aHR 1.884, 95% CI 1.448-2.449, p&lt;0.001), visceral-pleural invasion (aHR 1.096, 95% CI 0.905-1.329, p=0.35), lymphovascular invasion (aHR 1.747, 95% CI 1.441-2.117, p&lt;0.001), non-anatomic wedge resection (aHR 1.335, 95% CI 1.101-1.619, p=0.003), and adequacy of nodal sampling (e.g., 1-4 lymph nodes vs. ≥10 lymph nodes, aHR 1.392, 95% CI 1.149-1.687, p&lt;0.001). Using these parameters, a score was created reflecting the association between high-risk features and recurrence. The score ranged from 0-36, with higher scores reflecting higher cumulative incidence of recurrence. The score was further divided into low- (0-11, n=1,263, 33.3%; 5-yr recurrence risk 13.0%), moderate- (12-15, n=1,134, 29.9%; 5-yr recurrence risk 19.0%), and high-risk (16-36, n=1,402, 36.9%; 5-yr recurrence risk 27.1%) categories. Higher scores were also associated with diminished overall survival (median OS, low-risk: 9.0 yrs; moderate-risk: 7.3 yrs; high-risk: 5.4 yrs). The score was further tested in a cohort of 63,232 patients from the NCDB and higher scores remained associated with worse overall survival (median OS, low-risk: 9.4 yrs; moderate-risk: 8.0 yrs; high-risk: 6.3 yrs).

Conclusions: High-risk clinicopathologic features are associated with dramatically higher risk of recurrence and worse overall survival. Multivariable assessment of these features using a comprehensive yet pragmatic score may help to standardize adjuvant treatment eligibility following curative intent resection.

Citation Format: Brendan T. Heiden, Daniel B. Eaton, Su-Hsin Chang, Yan Yan, Martin W. Schoen, Bindiya G. Patel, Theodore S. Thomas, Bryan F. Meyers, Benjamin D. Kozower, Varun Puri. Comprehensive validation of high-risk clinicopathologic features in early-stage, node-negative non-small cell lung cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 734.

Assessment of Duration of Smoking Cessation Prior to Surgical Treatment of Non-small Cell Lung Cancer

OBJECTIVE

To define the relationship between the duration of smoking cessation and postoperative complications for patients with lung cancer undergoing surgical treatment.

BACKGROUND

Smoking increases the risk of postoperative morbidity and mortality in patients with lung cancer undergoing surgical treatment. Although smoking cessation before surgery can mitigate these risks, the ideal duration of preoperative smoking cessation remains unclear.

METHODS

Using a uniquely compiled Veterans Health Administration dataset, we performed a retrospective cohort study of patients with clinical stage I non-small cell lung cancer undergoing surgical treatment between 2006 and 2016. We characterized the relationship between duration of preoperative smoking cessation and risk of postoperative complications or mortality within 30-days using multivariable restricted cubic spline functions.

RESULTS

The study included a total of 9509 patients, of whom 6168 (64.9%) were smoking at the time of lung cancer diagnosis. Among them, only 662 (10.7%) patients stopped smoking prior to surgery. Longer duration between smoking cessation and surgery was associated with lower odds of major complication or mortality (adjusted odds ratio [aOR] for every additional week, 0.919; 95% confidence interval [CI], 0.850-0.993; P = 0.03). Compared to nonsmokers, patients who quit at least 3 weeks before surgery had similar odds of death or major complication (aOR, 1.005; 95% CI, 0.702-1.437; P = 0.98) whereas those who quit within 3 weeks of surgery had significantly higher odds of death or major complication (aOR, 1.698; 95% CI, 1.203-2.396; P = 0.003).

CONCLUSION

Smoking cessation at least 3 weeks prior to the surgical treatment of lung cancer is associated with reduced morbidity and mortality. Providers should aggressively encourage smoking cessation in the preoperative period, since it can disproportionately impact outcomes in early-stage lung cancer.

Association between imaging surveillance frequency and outcomes following surgical treatment of early-stage lung cancer

BACKGROUND

Recent studies have suggested that more frequent postoperative surveillance imaging via computed tomography following lung cancer resection may not improve outcomes. We sought to validate these findings using a uniquely compiled dataset from the Veterans Health Administration, the largest integrated health-care system in the United States.

METHODS

We performed a retrospective cohort study of veterans with pathologic stage I non-small cell lung cancer receiving surgery (2006-2016). We assessed the relationship between surveillance frequency (chest computed tomography scans within 2 years after surgery) and recurrence-free survival and overall survival.

RESULTS

Among 6171 patients, 3047 (49.4%) and 3124 (50.6%) underwent low-frequency (<2 scans per year; every 6-12 months) and high-frequency (≥2 scans per year; every 3-6 months) surveillance, respectively. Factors associated with high-frequency surveillance included being a former smoker (vs current; adjusted odds ratio [aOR] = 1.18, 95% confidence interval [CI] = 1.05 to 1.33), receiving a wedge resection (vs lobectomy; aOR = 1.21, 95% CI = 1.05 to 1.39), and having follow-up with an oncologist (aOR = 1.58, 95% CI = 1.42 to 1.77), whereas African American race was associated with low-frequency surveillance (vs White race; aOR = 0.64, 95% CI = 0.54 to 0.75). With a median (interquartile range) follow-up of 7.3 (3.4-12.5) years, recurrence was detected in 1360 (22.0%) patients. High-frequency surveillance was not associated with longer recurrence-free survival (adjusted hazard ratio = 0.93, 95% CI = 0.83 to 1.04, P = .22) or overall survival (adjusted hazard ratio = 1.04, 95% CI = 0.96 to 1.12, P = .35).

CONCLUSIONS

We found that high-frequency surveillance does not improve outcomes in surgically treated stage I non-small cell lung cancer. Future lung cancer treatment guidelines should consider less frequent surveillance imaging in patients with stage I disease.

Association Between Surgical Quality Metric Adherence and Overall Survival Among US Veterans With Early-Stage Non-Small Cell Lung Cancer

Importance

Surgical resection remains the preferred treatment for functionally fit patients diagnosed with early-stage non-small cell lung cancer (NSCLC). Process-based intraoperative quality metrics (QMs) are important for optimizing long-term outcomes following curative-intent resection.

Objective

To develop a practical surgical quality score for patients diagnosed with clinical stage I NSCLC who received definitive surgical treatment.

Design, Setting, and Participants

This retrospective cohort study used a uniquely compiled data set of US veterans diagnosed with clinical stage I NSCLC who received definitive surgical treatment from October 2006 through September 2016. The data were analyzed from April 1 to September 1, 2022. Based on contemporary treatment guidelines, 5 surgical QMs were defined: timely surgery, minimally invasive approach, anatomic resection, adequate lymph node sampling, and negative surgical margin. The study developed a surgical quality score reflecting the association between these QMs and overall survival (OS), which was further validated in a cohort of patients using data from the National Cancer Database (NCDB). The study also examined the association between the surgical quality score and recurrence-free survival (RFS).

Exposures

Surgical treatment of early-stage NSCLC.

Main Outcomes and Measures

Overall survival and RFS.

Results

The study included 9628 veterans who underwent surgical treatment between 2006 and 2016. The cohort consisted of 1446 patients who had a mean (SD) age of 67.6 (7.9) years and included 9278 males (96.4%) and 350 females (3.6%). Among the cohort, 5627 individuals (58.4%) identified as being smokers at the time of surgical treatment. The QMs were met as follows: timely surgery (6633 [68.9%]), minimally invasive approach (3986 [41.4%]), lobectomy (6843 [71.1%]) or segmentectomy (532 [5.5%]), adequate lymph node sampling (3278 [34.0%]), and negative surgical margin (9312 [96.7%]). The median (IQR) follow-up time was 6.2 (2.5-11.4) years. An integer-based score (termed the Veterans Affairs Lung Cancer Operative quality [VALCAN-O] score) from 0 (no QMs met) to 13 (all QMs met) was constructed, with higher scores reflecting progressively better risk-adjusted OS. The median (IQR) OS differed substantially between the score categories (score of 0-5 points, 2.6 [1.0-5.7] years of OS; 6-8 points, 4.3 [1.7-8.6] years; 9-11 points, 6.3 [2.6-11.4] years; and 12-13 points, 7.0 [3.0-12.5] years; P < .001). In addition, risk-adjusted RFS improved in a stepwise manner between the score categories (6-8 vs 0-5 points, multivariable-adjusted hazard ratio [aHR], 0.62; 95% CI, 0.48-0.79; P < .001; 12-13 vs 0-5 points, aHR, 0.39; 95% CI, 0.31-0.49; P < .001). In the validation cohort, which included 107 674 nonveteran patients, the score remained associated with OS.

Conclusions and Relevance

The findings of this study suggest that adherence to intraoperative QMs may be associated with improved OS and RFS. Efforts to improve adherence to surgical QMs may improve patient outcomes following curative-intent resection of early-stage lung cancer.

Comparison Between Veteran and Non-Veteran Populations With Clinical Stage I Non-small Cell Lung Cancer Undergoing Surgery

OBJECTIVE

The aim of this study was to compare quality of care and outcomes between Veteran and non-Veteran patients undergoing surgery for clinical stage I non-small cell lung cancer (NSCLC).

BACKGROUND

Prior studies and the lay media have questioned the quality of care that Veterans with lung cancer receive through the VHA. We hypothesized Veterans undergoing surgery for early-stage NSCLC receive high quality care and have similar outcomes compared to the general population.

METHODS

We performed a retrospective cohort study of patients with clinical stage I NSCLC undergoing resection from 2006 to 2016 using a VHA dataset. Propensity score matching for baseline patient- and tumor-related variables was used to compare operative characteristics and outcomes between the VHA and the National Cancer Database (NCDB).

RESULTS

The unmatched cohorts included 9981 VHA and 176,304 NCDB patients. The VHA had more male, non-White patients with lower education levels, higher incomes, and higher Charlson/Deyo scores. VHA patients had inferior unadjusted 30-day mortality (VHA 2.1% vs NCDB 1.7%, P = 0.011) and median overall survival (69.0 vs 88.7 months, P < 0.001). In the propensity matched cohort of 6792 pairs, VHA patients were more likely to have minimally invasive operations (60.0% vs 39.6%, P < 0.001) and only slightly less likely to receive lobectomies (70.1% vs 70.7%, P = 0.023). VHA patients had longer lengths of stay (8.1 vs 7.1 days, P < 0.001) but similar readmission rates (7.7% vs 7.0%, P = 0.132). VHA patients had significantly better 30-day mortality (1.9% vs 2.8%, P < 0.001) and median overall survival (71.4 vs 65.2 months, P < 0.001).

CONCLUSIONS

Despite having more comorbidities, Veterans receive exceptional care through the VHA with favorable outcomes, including significantly longer overall survival, compared to the general population.

Assessment of Updated Commission on Cancer Guidelines for Intraoperative Lymph Node Sampling in Early Stage NSCLC

INTRODUCTION

The American College of Surgeons Commission on Cancer recently updated its sampling recommendations for early stage NSCLC from at least 10 lymph nodes to at least one N1 (hilar) and three N2 (mediastinal) lymph node stations. Nevertheless, intraoperative lymph node sampling minimums remain subject to debate. We sought to evaluate these guidelines in patients with early stage NSCLC.

METHODS

We performed a cohort study using a uniquely compiled data set from the Veterans Health Administration. We manually abstracted data from operative notes and pathology reports of patients with clinical stage I NSCLC receiving surgery (2006-2016). Adequacy of lymph node sampling was defined using count-based (≥10 lymph nodes) and station-based (≥three N2 and one N1 nodal stations) minimums. Our primary outcome was recurrence-free survival. Secondary outcomes were overall survival and pathologic upstaging.

RESULTS

The study included 9749 patients. Count-based and station-based sampling guidelines were achieved in 3302 (33.9%) and 2559 patients (26.3%), respectively, with adherence to either sampling guideline increasing over time from 35.6% (2006) to 49.1% (2016). Adherence to station-based sampling was associated with improved recurrence-free survival (multivariable-adjusted hazard ratio = 0.815, 95% confidence interval: 0.667-0.994, p = 0.04), whereas adherence to count-based sampling was not (adjusted hazard ratio = 0.904, 95% confidence interval: 0.757-1.078, p = 0.26). Adherence to either station-based or count-based guidelines was associated with improved overall survival and higher likelihood of pathologic upstaging.

CONCLUSIONS

Our study supports station-based sampling minimums (≥three N2 and one N1 nodal stations) for early stage NSCLC; however, the marginal benefit compared with count-based guidelines is minimal. Further efforts to promote widespread adherence to intraoperative lymph node sampling minimums are critical for improving patient outcomes after curative-intent lung cancer resection.

Racial Disparities in the Surgical Treatment of Clinical Stage I Non-Small Cell Lung Cancer Among Veterans

BACKGROUND

Prior studies in the civilian population have reported racial disparities in lung cancer outcomes following surgical treatment, including inferior quality of care and worse survival. It is unclear if racial disparities exist in the Veterans Health Administration (VHA), the largest integrated health care system in the United States.

RESEARCH QUESTION

Do racial disparities affect early-stage non-small cell lung cancer (NSCLC) outcomes following surgical treatment within the VHA?

STUDY DESIGN AND METHODS

This retrospective cohort study was conducted in veterans with clinical stage I NSCLC undergoing surgical treatment in the VHA system. Demographic characteristics, access to care, surgical quality measures, and short- and long-term oncologic outcomes between White and Black veterans were evaluated.

RESULTS

From 2006 to 2016, a total of 18,800 veterans with clinical stage I NSCLC were included. The rates of definitive surgical treatment were similar between Black (57.3%) and White (58.1%) veterans (P = .42). The final study cohort included 9,842 patients receiving surgical treatment, of whom 8,356 (84.9%) were White and 1,486 (15.1%) were Black. Black patients were younger and more likely to smoke, although comorbidities were similar between the two groups. Black patients were somewhat less likely to receive adequate lymph node sampling (30.6% vs 33.3%; P = .050); however, other access-to-care metrics and surgical quality measures, including rates of anatomic lobectomy (71.9% vs 69.4%; P = .189) and positive margins (3.2% vs 3.1%; P = .955), were similar between the two groups. Although Black veterans were less likely to experience major postoperative complications, there was no difference in 30-day readmission, 30-day mortality, or disease-free survival between the two groups. Black patients had significantly better risk-adjusted overall survival (hazard ratio, 0.802; 95% CI, 0.729-0.883; P < .001).

INTERPRETATION

Among veterans with NSCLC undergoing surgical treatment through the VHA, Black patients received comparable care with equivalent if not superior outcomes compared with White patients.

Intraoperative quality metrics and association with survival following lung cancer resection

8502

Background: Surgical resection remains the preferred treatment for functionally fit patients with clinical stage I non-small cell lung cancer (NSCLC). Process-based intra-operative quality metrics (QMs) are important for optimizing long-term outcomes following curative-intent resection. We sought to characterize overall survival using a novel surgical quality score. Methods: We performed a retrospective cohort study using a uniquely compiled dataset of US Veterans with clinical stage I NSCLC receiving definitive surgical treatment. Based on contemporary treatment guidelines, we defined five surgical QMs: timely surgery (within 12 weeks of diagnosis), minimally invasive approach, anatomic resection via lobectomy, adequate nodal sampling (≥10 nodes), and negative margin. Using a multivariable Cox proportional hazards model, we developed a surgical quality score reflecting the relationship between these QMs and overall survival (OS). We also examined the relationship between this score and disease-free survival (DFS). Results: The study included 9,628 Veterans undergoing surgical treatment between 2006 and 2016. QMs were met as follows: timely surgery (n=6,633, 68.9%), minimally invasive approach (n=3,986, 41.4%), lobectomy (n=6,843, 71.1%), adequate nodal sampling (n=3,278, 34.1%), and negative surgical margin (n=9,312, 96.7%). The median (IQR) follow-up was 6.2 (2.5-11.4) years. A normalized score from 0 (no QMs met) to 100 (all QMs met) was constructed, with higher scores reflecting progressively improved risk-adjusted OS (Table). The median (IQR) OS was 86.8 (37.8-149.6) months in the highest score quintile versus 25.3 (7.1-45.8) months in the lowest score quintile. Recurrence was detected in 2,268 (23.6%) patients. Higher surgical quality score was associated with improved DFS (multivariable-adjusted hazard ratio, aHR 0.494, 95% CI 0.245-0.997). Conclusions: Adherence to intra-operative QMs is associated with markedly improved overall and disease-free survival. Efforts to improve adherence to surgical QMs can dramatically improve patient outcomes following curative-intent resection of early-stage lung cancer. [Table: see text]

The Impact of Persistent Smoking After Surgery on Long-term Outcomes After Stage I Non-small Cell Lung Cancer Resection

BACKGROUND

Smoking at the time of surgical treatment for lung cancer increases the risk for perioperative morbidity and mortality. The prevalence of persistent smoking in the postoperative period and its association with long-term oncologic outcomes are poorly described.

RESEARCH QUESTION

What is the relationship between persistent smoking and long-term outcomes in early-stage lung cancer after surgical treatment?

STUDY DESIGN AND METHODS

We performed a retrospective cohort study using a uniquely compiled Veterans Health Administration dataset of patients with clinical stage I non-small cell lung cancer (NSCLC) undergoing surgical treatment between 2006 and 2016. We defined persistent smoking as individuals who continued smoking 1 year after surgery and characterized the relationship between persistent smoking and disease-free survival and overall survival.

RESULTS

This study included 7,489 patients undergoing surgical treatment for clinical stage I NSCLC. Of 4,562 patients (60.9%) who were smoking at the time of surgery, 2,648 patients (58.0%) continued to smoke at 1 year after surgery. Among 2,927 patients (39.1%) who were not smoking at the time of surgical treatment, 573 (19.6%) relapsed and were smoking at 1 year after surgery. Persistent smoking at 1 year after surgery was associated with significantly shorter overall survival (adjusted hazard ration [aHR], 1.291; 95% CI, 1.197-1.392; P < .001). However, persistent smoking was not associated with inferior disease-free survival (aHR, 0.989; 95% CI, 0.884-1.106; P = .84).

INTERPRETATION

Persistent smoking after surgery for stage I NSCLC is common and is associated with inferior overall survival. Providers should continue to assess smoking habits in the postoperative period given its disproportionate impact on long-term outcomes after potentially curative treatment for early-stage lung cancer.

Analysis of Delayed Surgical Treatment and Oncologic Outcomes in Clinical Stage I Non-Small Cell Lung Cancer

IMPORTANCE

The association between delayed surgical treatment and oncologic outcomes in patients with non-small cell lung cancer (NSCLC) is poorly understood given that prior studies have used imprecise definitions for the date of cancer diagnosis.

OBJECTIVE

To use a uniform method to quantify surgical treatment delay and to examine its association with several oncologic outcomes.

DESIGN, SETTING, AND PARTICIPANTS

This retrospective cohort study was conducted using a novel data set from the Veterans Health Administration (VHA) system. Included patients had clinical stage I NSCLC and were undergoing resection from 2006 to 2016 within the VHA system. Time to surgical treatment (TTS) was defined as the time between preoperative diagnostic computed tomography imaging and surgical treatment. We evaluated the association between TTS and several delay-associated outcomes using restricted cubic spline functions. Data analyses were performed in November 2021.

EXPOSURE

Wait time between cancer diagnosis and surgical treatment (ie, TTS).

MAIN OUTCOMES AND MEASURES

Several delay-associated oncologic outcomes, including pathologic upstaging, resection with positive margins, and recurrence, were assessed. We also assessed overall survival.

RESULTS

Among 9904 patients who underwent surgical treatment for clinical stage I NSCLC, 9539 (96.3%) were men, 4972 individuals (50.5%) were currently smoking, and the mean (SD) age was 67.7 (7.9) years. The mean (SD) TTS was 70.1 (38.6) days. TTS was not associated with increased risk of pathologic upstaging or positive margins. Recurrence was detected in 4158 patients (42.0%) with median (interquartile range) follow-up of 6.15 (2.51-11.51) years. Factors associated with increased risk of recurrence included younger age (hazard ratio [HR] for every 1-year increase in age, 0.992; 95% CI, 0.987-0.997; P = .003), higher Charlson Comorbidity Index score (HR for every 1-unit increase in composite score, 1.055; 95% CI, 1.037-1.073; P < .001), segmentectomy (HR vs lobectomy, 1.352; 95% CI, 1.179-1.551; P < .001) or wedge resection (HR vs lobectomy, 1.282; 95% CI, 1.179-1.394; P < .001), larger tumor size (eg, 31-40 mm vs <10 mm; HR, 1.209; 95% CI, 1.051-1.390; P = .008), higher tumor grade (eg, II vs I; HR, 1.210; 95% CI, 1.085-1.349; P < .001), lower number of lymph nodes examined (eg, ≥10 vs <10; HR, 0.866; 95% CI, 0.803-0.933; P < .001), higher pathologic stage (III vs I; HR, 1.571; 95% CI, 1.351-1.837; P < .001), and longer TTS, with increasing risk after 12 weeks. For each week of surgical delay beyond 12 weeks, the hazard for recurrence increased by 0.4% (HR, 1.004; 95% CI, 1.001-1.006; P = .002). Factors associated with delayed surgical treatment included African American race (odds ratio [OR] vs White race, 1.267; 95% CI, 1.112-1.444; P < .001), higher area deprivation index [ADI] score (OR for every 1 unit increase in ADI score, 1.005; 95% CI, 1.002-1.007; P = .002), lower hospital case load (OR for every 1-unit increase in case load, 0.998; 95% CI, 0.998-0.999; P = .001), and year of diagnosis, with less recent procedures more likely to have delay (OR for each additional year, 0.900; 95% CI, 0.884-0.915; P < .001). Patients with surgical treatment within 12 weeks of diagnosis had significantly better overall survival than those with procedures delayed more than 12 weeks (HR, 1.132; 95% CI, 1.064-1.204; P < .001).

CONCLUSIONS AND RELEVANCE

Using a more precise definition for TTS, this study found that surgical procedures delayed more than 12 weeks were associated with increased risk of recurrence and worse survival. These findings suggest that patients with clinical stage I NSCLC should undergo expeditious treatment within that time frame.