Assessment of volume reduction effect after lung lobectomy for cancer

Factors Associated With Radiological Lung Growth Rate After Lobectomy in Patients With Lung Cancer

INTRODUCTION

This study is a retrospective study. This study aims to explore the association between lobectomy in lung cancer patients and subsequent compensatory lung growth (CLG), and to identify factors that may be associated with variations in CLG.

METHODS

207 lung cancer patients who underwent lobectomy at Yunnan Cancer Hospital between January 2020 and December 2020. All patients had stage IA primary lung cancer and were performed by the same surgical team. And computed tomography examinations were performed before and 1 y postoperatively. Based on computed tomography images, the volume of each lung lobe was measured using computer software and manual, the radiological lung weight was calculated. And multiple linear regressions were used to analyze the factors related to the increase in postoperative lung weight.

RESULTS

One year after lobectomy, the radiological lung weight increased by an average of 112.4 ± 20.8%. Smoking history, number of resected lung segments, preoperative low attenuation volume, intraoperative arterial oxygen partial pressure/fraction of inspired oxygen ratio and postoperative visual analog scale scores at 48 h were significantly associated with postoperative radiological lung weight gain.

CONCLUSIONS

Our results suggest that CLG have occurred after lobectomy in adults. In addition, anesthetists should maintain high arterial oxygen partial pressure/fraction of inspired oxygen ratio during one-lung ventilation and improve acute postoperative pain to benefit CLG.

Robust imaging approach for precise prediction of postoperative lung function in lung cancer patients prior to curative operation

BACKGROUND

To create a combined variable integrating both ventilation and perfusion as measured by preoperative dual-energy computed tomography (DECT), compare the results with predicted postoperative (PPO) lung function as estimated using conventional methods, and assess agreement with actual postoperative lung function.

METHODS

A total of 33 patients with lung cancer who underwent curative surgery after DECT and perfusion scan were selected. Ventilation and perfusion values were generated from DECT data. In the "combined variable method," these two variables and clinical variables were linearly regressed to estimate PPO lung function. Six PPO lung function parameters (segment counting, perfusion scan, volume analysis, ventilation map, perfusion map, and combined variable) were compared with actual postoperative lung function using an intraclass correlation coefficient (ICC).

RESULTS

The segment counting method produced the highest ICC for forced vital capacity (FVC) at 0.93 (p < 0.05), while the segment counting and perfusion map methods produced the highest ICC for forced expiratory volume in 1 second (FEV1 ; both 0.89, p < 0.05). The highest ICC value when using the combined variable method was for FEV1 /FVC (0.75, p < 0.05) and diffusing capacity of the lung for carbon monoxide (DLco; 0.80, p < 0.05) when using the perfusion map method. Overall, the perfusion map and ventilation map provided the best performance, followed by volume analysis, segment counting, perfusion scan, and the combined variable.

CONCLUSIONS

Use of DECT image processing to predict postoperative lung function produced better agreement with actual postoperative lung function than conventional methods. The combined variable method produced ICC values of 0.8 or greater for FVC and FEV1 .

Predictive factors inhibiting recovery of the respiratory function after anatomical pulmonary resection

PURPOSE

Some patients have worse actual observed postoperative (apo) respiratory function values than predicted postoperative (ppo) values. The present study therefore clarified the predictive factors that hinder the recovery of the postoperative respiratory function.

METHODS

This study enrolled 255 patients who underwent anatomical pulmonary resection for lung cancer. A pulmonary function test (PFT) was carried out before surgery and at one, three, and six months after surgery. In each surgical procedures, the forced expiratory volume in 1 s (FEV1) ratio was calculated as the apo value divided by the ppo value. In addition, we investigated the predictive factors that inhibited postoperative respiratory function improvement in patients with an FEV1 ratio < 1.0 at 6 months after surgery.

RESULTS

The FEV1 ratio gradually improved over time in all surgical procedures. However, 49 of 196 patients who underwent a PFT at 6 months after surgery had an FEV1 ratio < 1.0. In a multivariate analysis, right side, upper lobe, segmentectomy and pleurodesis for prolonged air leakage were independent significant predictors of a decreased FEV1 ratio (p = 0.003, 0.006, 0.001, and 0.009, respectively).

CONCLUSION

Pleurodesis was the only controllable factor that might help preserve the postoperative respiratory function. Thus, the intraoperative management of air leakage is important.

Comparison between functional lung volume measurement and segment counting for predicting postoperative pulmonary function after pulmonary resection in lung cancer patients

BACKGROUND

Functional lung volume (FLV) obtained from computed tomography images was a breakthrough for lung imaging and functional assessment. We compared the accuracy of the FLV measurement method and the segment-counting (SC) method in predicting postoperative pulmonary function.

METHODS

A total of 113 patients who underwent two thoracoscopic surgeries were enrolled in our study. We predicted postoperative pulmonary function by the FLV measurement method and the SC method. Novel formulas based on the FLV measurement method were established using linear regression equations between the factors affecting pulmonary function and the measured values.

RESULTS

The predicted postoperative forced vital capacity (ppoFVC) and forced expiratory volume in 1 s (ppoFEV1) measured by the 2 methods showed high concordance between the actual postoperative forced vital capacity (postFVC) and the forced expiratory volume in 1 s (postFEV1) [r = 0.762, P < 0.001 (FLV method) and r = 0.759, P < 0.001 (SC method) for FVC; r = 0.790, P < 0.001 (FLV method) and r = 0.795, P < 0.001 (SC method) for FEV1]. Regression analysis showed that the measured preoperative pulmonary function parameters (FVC, FEV1) and the ratio of reduced FLV to preoperative FLV were significantly associated with the actual postoperative values and could predict these parameters (all P < 0.001). The feasibility of using these equations [postFVC = 0.8 × FVC - 0.784 × ΔFLV/FLV + 0.283 (R² = 0.677, RSD = 0.338), postFEV1 = 0.766 × FEV1 - 0.694 × ΔFLV/FLV + 0.22 (R² = 0.743, RSD = 0.265)] to predict the pulmonary function parameters after wedge resection was also verified.

CONCLUSIONS

The new FLV measurement method is valuable for predicting postoperative pulmonary function in patients undergoing lung resection surgery, with accuracy and consistency similar to those of the conventional SC method.

Comparison between quantitative computed tomography, scintigraphy, and anatomical methods for prediction of postoperative FEV1 and DLCO: effects of chronic obstructive pulmonary disease status and resected lobes

Background

Postoperative assessment of pulmonary function is important for estimating the risk of thoracic surgery and long-term disability following pulmonary resection, including predicted postoperative (ppo) forced expiratory volume (FEV) in one second (ppoFEV₁) and percent predicted lung diffusion capacity for carbon monoxide (ppo%DLCO) estimation. The ppo values were compared using four different estimation methods between chronic obstructive pulmonary disease (COPD) and non-COPD patients and according to the resected lobe.

Methods

This prospective study included 59 eligible patients requiring single lobectomy and succeeded in performing pulmonary function tests at 3 and 12 months after lobectomy. The ppoFEV₁ and ppo%DLCO were compared with poFEV₁ and po%DLCO obtained at 3 and 12 months after lobectomy. The ppo values were estimated using the four usual methods: the 19-segment anatomical technique (S), perfusion scintigraphy (Q), quantitative CT (CT), and quantitative CT with low attenuation volume (CT_LAV) subtraction.

Results

For non-COPD and COPD patients, the smallest mean difference between ppo and po values was observed by S for FEV₁ and %DLCO. Based on the resected lobe, the smallest mean difference was observed by (I) Q for right upper lobectomy (RUL) excluding %DLCO at 12 months by S, (II) S for left upper lobectomy (LUL), (III) CT and CT_LAV for right lower lobectomy (RLL), and (IV) CT and CT_LAV for left lower lobectomy (LLL) at 12 months. The ppo values calculated by S for RUL (FEV₁ at 3 and 12 months and %DLCO at 3 months) and by all four methods for LLL (FEV₁ and %DLCO at 3 months) were smaller than the po values.

Conclusions

The S method is adequate for calculating ppoFEV₁ and ppo%DLCO when patients are classified as non-COPD and COPD. However, S sometimes overestimates the ppoFEV₁ and ppo%DLCO when patients are classified according to the resected lobe. The CT_LAV method may be the method of choice instead of S for calculating ppoFEV₁ and ppo%DLCO in patients who undergo lung lobectomy despite the presence or absence of airflow limitation.

Predicting Postoperative Lung Function Following Lung Cancer Resection: A Systematic Review and Meta-analysis

BACKGROUND

Lung resection remains the gold standard treatment for early stage lung cancer; prediction of postoperative lung function is a key selection criterion for surgery with the aim of determining risk of postoperative dyspnoea. We aimed to identify the different prediction techniques used, and compare their accuracy.

METHODS

A systematic review and meta-analysis sought to synthesise studies conducted that assess prediction of postoperative lung function up to 18/02/2018 (n = 135). PROBAST was used to assess risk of bias in studies, 17 studies were judged to be at low risk of bias.

FINDINGS

Meta-analysis revealed CT volume and density measurement to be the most accurate (mean difference 71 ml) and precise (standard deviation 207 ml) of the reported techniques used for predicting FEV1; evidence for predicting gas transfer was lacking.

INTERPRETATION

The evidence suggests using CT volume and density is the preferred technique in the prediction of postoperative FEV1. Further studies are required to ensure that the methods and thresholds we propose are linked to patient reported outcomes.

FUNDING

Salary support for NKO, RM, PN, BN, and AMT was provided by University Hospitals Birmingham NHS Foundation Trust.

Impact of age on the recovery of six-minute walking distance after lung cancer surgery: a retrospective cohort study

PURPOSE

The aim was to investigate the relationship of age for recovery of six-minute walking distance (6MWD), pulmonary function, and health-related quality of life (HRQOL) after lung cancer surgery.

METHODS

Primary outcome was the 6MWD recovery until 6 months after surgery. Secondary outcome was the recoveries of forced expiratory volume in 1 s (FEV₁) and HRQOL until 6 months after surgery. Linear mixed-effects model was used to estimate the association of age to the outcomes.

RESULTS

A total of 311 lung cancer patients were included. All the 6MWD, FEV₁, and HRQOL decreased after surgery (- 32 m, - 0.39L, and - 2 scores, respectively, p = 0.027-p < 0.001). While 6MWD increased every month after surgery (5 m/month, 95% confidence interval (CI); 4-7, p < 0.001), the recovery decreased, as the age increased 1 standard deviation (SD) (i.e., 9 years) (- 2 m/month; 95% CI - 3 to - 1, p < 0.001). While FEV₁ increased every month after surgery (0.03 L/month; 95% CI 0.02-0.03, p < 0.001), the recovery increased, as the age increased by 1 SD (0.01 L/month; 95% CI 0.00-0.01, p = 0.003), which was opposite to the 6MWD recovery. While the postoperative HRQOL recovered every month (2 score/month; 95% CI 1-2, p < 0.001), there was no significant association between the recovery and age (0 score/month; 95% CI - 1 to 0, p = 0.5).

CONCLUSIONS

The 6MWD recovery delayed in elderly patients, which was not related to their FEV₁-and HRQOL recoveries. Postoperative walking training would be important for the elderly lung cancer patients.

Postoperative pulmonary function changes according to the resected lobe: a 1-year follow-up study of lobectomized patients

Background

Pulmonary function and patient complaints appear to improve up to 12 months after lobectomy but long-term prospective studies based on clinical data are scarce. Improvement in pulmonary function may depend on the area and extent of the resection and the time from the operation. This prospective study aimed to determine pulmonary function changes according to the resected lobe.

Methods

This prospective study included 59 patients requiring single lobectomy. Total volume and low-attenuation volume (LAV) for each lobe and the entire lungs were calculated based on helical computed tomography images. Vital capacity (VC), forced expiratory volume in one second (FEV₁), percent FEV₁ (%FEV₁), percent lung diffusion capacity for carbon monoxide (%DL_co), %DL_co divided by the alveolar volume (%DL_co/V_A), modified Medical Research Council (mMRC) grades, and COPD Assessment Test (CAT) scores were compared at 3, 6, and 12 months after surgery.

Results

VC was higher at 12 months than at 3 months after right upper lobectomy (RUL) or right lower lobectomy (RLL). FEV₁ and %FEV₁ were higher at 12 months than at 6 months after left lower lobectomy (LLL). %DL_co was higher at 12 months than at 3 months after RUL or left upper lobectomy (LUL). DL_co/V_A, mMRC grades, and CAT scores did not change significantly in the period from 3 to 12 months after any lobectomy procedure. Compared to the predicted postoperative values, the observed values of VC for RUL, RLL, and LUL; FEV₁ for RLL; %FEV₁ for RLL and LUL; %DL_co for LUL; and %DL_co/V_A for all lobectomy procedures were higher at 12 months.

Conclusions

Improvements in pulmonary function and symptoms varied according to the resected lobe. Some of the observed pulmonary function values were higher than the predicted postoperative values. Pulmonary function changes may be related to the location, volume, and extent of emphysematous changes.

Preoperative risk assessment with computed tomography in patients undergoing lung cancer surgery

Background

Although whole lung computed tomography (CT) is included in the routine workup before lung cancer surgery, it is not utilized to assess the preoperative pulmonary function.

Methods

Two hundred ninety patients (development cohort) who underwent lung lobectomy for cancer in our institute and another 100 patients (validation cohort) who subsequently underwent the same operation in a referral hospital were included. The total lung volume (TLV) and emphysematous lung volume (ELV) were obtained by quantitative CT.

Results

The TLV was higher in patients with a smoking history than in those without. The ELV to the TLV was higher in elderly patients than in younger patients. The regression equation for forced vital capacity (FVC) and forced expiratory volume in 1 second (FEV₁) were developed using CT-derived variables, together with sex, age, height, and smoking habit, by a multiple regression analysis in the development cohort. The regression equation-based FVC and FEV₁ were significantly correlated with the actual FVC and FEV₁ in the development cohort, as well as in the validation cohort. The predicted postoperative FEV₁ (ppo%FEV₁) calculated based on the regression equation was also correlated with the postoperative FEV₁ value obtained by the conventional method (R=0.53), and the regression equation-based ppo%FEV₁ was a significant predictor of postoperative cardiopulmonary complications (P=0.02).

Conclusions

Whole lung CT can be used to assess the preoperative pulmonary function in patients undergoing lobectomy for cancer. This method may be helpful in preoperative risk assessment, particularly in patients who have difficulty in implementation of spirometry.

Predicting the response to a bronchodilator in patients with airflow obstruction and lung cancer

BACKGROUND

The aim of the present study was to clarify the predictors of the response of patients with resectable lung cancer and untreated airflow obstruction to tiotropium, an antimuscarinic bronchodilator.

METHODS

Tiotropium was administered to 29 preoperative patients with untreated airflow obstruction. The forced vital capacity (FVC) and forced expiratory volume in 1 s (FEV₁) were measured before and after the introduction of tiotropium. The response to tiotropium was determined based on the percentage gain in the FEV₁. The volume of the total lung area (TLV) and the low-attenuation area (LAA) was measured by deep inspiratory computed tomography based on the predefined thresholds for attenuation values.

RESULTS

The introduction of tiotropium resulted in a 15% gain in the FEV₁ (P < 0.001). A univariate regression analysis revealed that the FVC/TLV was the best predictor of the gain in FEV₁, followed by the FEV₁/FVC. Based on the results of a multiple regression analysis, a regression equation to predict a gain in the FEV₁ was generated using the FVC, TLV, and LAA. A receiver operating characteristic curve analysis revealed that this equation led to the highest area under the curve for predicting a major response to tiotropium, followed by the FVC/TLV and FEV₁/FVC. Postoperatively, six of the 20 minor responders experienced a progression of dyspnea. In contrast, none of the major responders experienced a progression of dyspnea (P < 0.05).

CONCLUSIONS

We developed an equation for predicting the response to tiotropium using parameters obtained from spirometry and quantitative computed tomography. A large-scale study to validate the usefulness of this equation is warranted.

CT Radiomics in Thoracic Oncology: Technique and Clinical Applications

Precision medicine offers better treatment options and improved survival for cancer patients based on individual variability. As the success of precision medicine depends on robust biomarkers, the requirement for improved imaging biomarkers that reflect tumor biology has grown exponentially. Radiomics, the field of study in which high-throughput data are generated and large amounts of advanced quantitative features are extracted from medical images, has shown great potential as a source of quantitative biomarkers in the field of oncology. Radiomics provides quantitative information about the morphology, texture, and intratumoral heterogeneity of the tumor itself as well as features related to pulmonary function. Hence, radiomics data can be used to build descriptive and predictive clinical models that relate imaging characteristics to tumor biology phenotypes. In this review, we describe the workflow of CT radiomics, types of CT radiomics, and its clinical application in thoracic oncology.

Lung cancer and chronic obstructive pulmonary disease: From a clinical perspective

Chronic obstructive pulmonary disease (COPD) and lung cancer are devastating pulmonary diseases that commonly coexist and present a number of clinical challenges. COPD confers a higher risk for lung cancer development, but available chemopreventive measures remain rudimentary. Current studies have shown a marked benefit of cancer screening in the COPD population, although challenges remain, including the common underdiagnosis of COPD. COPD-associated lung cancer presents distinct clinical features. Treatment for lung cancer coexisting with COPD is challenging as COPD may increase postoperative morbidities and decrease survival. In this review, we outline current progress in the understanding of the clinical association between COPD and lung cancer, and suggest possible cancer prevention strategies in this patient population.

Evaluation of postoperative lung volume and perfusion changes by dual-energy computed tomography in patients with lung cancer

PURPOSE

The aim of our study was to retrospectively evaluate postoperative physiologic changes in lung cancer patients using dual-energy CT (DECT), and develop modified methods reflecting postoperative change for predicting pulmonary function.

METHODS AND MATERIALS

88 patients (M:F=64:24; mean age, 63.5 years) with lung cancer who underwent DECT and pulmonary function tests before and after operation were included. Volume and iodine values for perfusion of each lobe were quantified. The predicted postoperative FEV1 using the current method was calculated by multiplying the preoperative FEV1 by the fractional contribution of perfusion of the remaining lung. The modified method reflecting postoperative volume change was compared to the current method.

RESULTS

Postoperative lung volume showed compensatory increases in the contralateral and remaining ipsilateral lobes, with a significantly greater increase in the ipsilateral lobe than contralateral lobe (21.8%±46.2% vs. 10.0%±20.8%, P=0.031). Perfusion analysis showed blood volume increases in both ipsilateral and contralateral lobes without statistical differences (blood volume ratio difference, 29.2%±26.7 vs. 24.6%±16.5, P=0.368). The performance of the modified method considering postoperative lung volume change was comparable to that of the current method in the development and validation datasets (95% CI, -24.5% to 37.1% vs. -33.3% to 22.2% and -23.6% to 32.0% vs. -31.9% to 16.0%, respectively).

CONCLUSIONS

Postoperative compensatory increases in lung volume and perfusion occur in different ways. Our modified method incorporating postoperative lung volume changes can be considered a comparable method for prediction of postoperative lung function.

Regional Emphysema Score Predicting Overall Survival, Quality of Life, and Pulmonary Function Recovery in Early-Stage Lung Cancer Patients

INTRODUCTION

Pulmonary emphysema is a frequent comorbidity in lung cancer, but its role in tumor prognosis remains obscure. Our aim was to evaluate the impact of the regional emphysema score (RES) on a patient's overall survival, quality of life (QOL), and recovery of pulmonary function in stage I to II lung cancer.

METHODS

Between 1997 and 2009, a total of 1073 patients were identified and divided into two surgical groups-cancer in the emphysematous (group 1 [n = 565]) and nonemphysematous (group 2 [n = 435]) regions-and one nonsurgical group (group 3 [n = 73]). RES was derived from the emphysematous region and categorized as mild (≤5%), moderate (6%-24%), or severe (25%-60%).

RESULTS

In group 1, patients with a moderate or severe RES experienced slight decreases in postoperative forced expiratory volume in 1 second, but increases in the ratio of forced expiratory volume in 1 second to forced vital capacity compared with those with a mild RES (p < 0.01); however, this correlation was not observed in group 2. Posttreatment QOL was lower in patients with higher RESs in all groups, mainly owing to dyspnea (p < 0.05). Cox regression analysis revealed that patients with a higher RES had significantly poorer survival in both surgical groups, with adjusted hazard ratios of 1.41 and 1.43 for a moderate RES and 1.63 and 2.04 for a severe RES, respectively; however, this association was insignificant in the nonsurgical group (adjusted hazard ratio of 0.99 for a moderate or severe RES).

CONCLUSIONS

In surgically treated patients with cancer in the emphysematous region, RES is associated with postoperative changes in lung function. RES is also predictive of posttreatment QOL related to dyspnea in early-stage lung cancer. In both surgical groups, RES is an independent predictor of survival.

Size-capacity mismatch in the lung: a novel predictor for complications after lung cancer surgery

BACKGROUND

The aim of the present study was to make a combined pulmonary functional and anatomical assessment using spirometry and computed tomography (CT) to clarify the best predictor for cardiopulmonary complications after thoracoscopic major lung resection for cancer.

METHODS

We retrospectively reviewed our prospective database of 304 patients undergoing thoracoscopic major lung resection for cancer. The total lung volume (TLV) was measured preoperatively using deep-inspiratory CT by summing the voxels representing -600 to -1024 Hounsfield units. Forced vital capacity (FVC) was measured by spirometry. FVC/TLV was used to diagnose a lung size-function mismatch. We compared among FVC/TLV, conventional spirometric parameters, and the risk of postoperative cardiopulmonary complications.

RESULTS

Postoperative cardiopulmonary complications developed in 25 of 304 patients (8.2%). There were no cases of operative mortality. A stepwise logistic regression analysis revealed that a history of smoking and low FVC/TLV were independent risk factors for postoperative cardiopulmonary complications in various preoperative measurements. According to a receiver-operating characteristic analysis, FVC/TLV was the only variable that was statistically useful for predicting complications (area under the receiver-operating characteristic curve > 0.7).

CONCLUSIONS

Lung size-function mismatch was identified as the best predictor for cardiopulmonary complications after major lung resection for cancer among various spirometry- and CT-derived parameters. The usefulness of this parameter in screening for patients who are at risk of complications should be validated by a multicenter, large-scale study because it can be obtained through routine preoperative work.