Suitable Patient Selection and Optimal Timing of Treatment for Persistent Air Leak after Lung Resection.

OBJECTIVES: The choice of therapeutic intervention for postoperative air leak varies between institutions. We aimed to identify the optimal timing and patient criteria for therapeutic intervention in cases of postoperative air leaks after lung resection. METHODS: This study utilized data from a prospective multicenter observational study conducted in 2019. Among the 2187 cases in the database, 420 cases with air leaks on postoperative day 1 were identified. The intervention group underwent therapeutic interventions, such as pleurodesis or surgery, while the observation group was monitored without intervention. A comparison between the intervention group and the observation group were analyzed using the cumulative distribution and hazard functions. RESULTS: Forty-six patients (11.0%) were included in the intervention group. The multivariate analysis revealed that low body mass index (p = 0.019), partial resection (p = 0.010), intraoperative use of fibrin glue (p = 0.008), severe air leak on postoperative day 1 (p < 0.001), and high forced expiratory volume in 1 s (p = 0.021) were significant predictors of the requirement for intervention. The proportion of patients with persistent air leak in the observation group was 20% on postoperative day 5 and 94% on postoperative day 7. The hazard of air leak cessation peaked from postoperative day 3 to postoperative day 7. CONCLUSIONS: This research contributes valuable insights into predicting therapeutic interventions for postoperative air leaks and identifies scenarios where spontaneous cessation is probable. A validation through prospective studies is warranted to affirm these findings.

Tumor DNA in Peritoneal Lavage as a Novel Biomarker for Predicting Peritoneal Recurrence in Patients With Gastric Cancer.

BACKGROUND: Peritoneal lavage cytology positivity (CY1) has been identified as a prognostic factor for distant metastases that is equivalent to peritoneal dissemination in Japan. Peritoneal lavage cytology is usually diagnosed by microscopic findings; a diagnostic procedure using a liquid biopsy (LB) technique has not yet been established. PATIENTS AND METHODS: We evaluated the feasibility of a LB approach using peritoneal lavage samples from 15 patients with gastric cancer. Samples were collected from both the Douglas pouch and the left subdiaphragmatic area, and cell-free DNA was extracted for analysis of TP53 mutations using droplet digital polymerase chain reaction. RESULTS: All 10 patients with CY1 had positive cytology for the left subdiaphragmatic specimen. However, only six out of the 10 patients had positive cytology for their Douglas pouch specimens, and these six patients had peritoneal tumor DNA (ptDNA) in these specimens. In all five patients with CY0, ptDNA was not detected. The overall survival was significantly shorter in the ptDNA-positive group than in the ptDNA-negative group. The survival of the group with a high amount of DNA from free intraperitoneal cells (ficDNA) was significantly worse than that of those with a low amount. In contrast, the group with a high amount of DNA from peritoneal cell-free DNA (pcfDNA) had significantly better survival than the group with a low amount. CONCLUSION: LB cytology showed equivalent utility to that of conventional microscopic examinations regarding its diagnostic ability. Therefore ptDNA, pcfDNA and ifcDNA are expected to be useful as prognostic factors.

Optimal Chest Drainage Method After Anatomic Lung Resection: A Prospective Observational Study.

BACKGROUND: Several methods for chest drainage after pulmonary resection of malignant lung tumors exist, but consensus on the ideal method has not been reached. METHODS: We conducted a multicenter prospective observational study. We enrolled 2200 patients who underwent lung resection for lung tumors. Of the 1470 patients who underwent anatomic resection, 347 showed air leak on the morning of postoperative day 1. They were assigned to 3 groups according to the chest drainage method on postoperative day 1. RESULTS: Of 347 patients with postoperative air leaks, 107 (30.8%), 179 (51.6%), and 61 (17.6%) were assigned to water seal, continuous suction, and digital drainage, respectively. The median postoperative air leak duration was significantly longer with digital drainage (4.0 days) than with either water seal (2.5 days) or continuous suction (3.0 days; P = .009). Chest tubes were required for significantly more days on average with digital drainage (6.0 days) than with water seal (4.0 days) or continuous suction (4.0 days; P = .003). Prolongation of air leak duration was significantly more likely to occur in patients with body mass index <18.5 kg/m2 (hazard ratio [HR], 1.6; 95% CI, 1.1-2.3), moderate or severe air leak on postoperative day 1 (HR, 2.0; 95% CI, 1.5-2.6), or digital drainage (HR, 1.4; 95% CI, 1.01-1.9). CONCLUSIONS: Water seal was associated with significantly shorter duration of postoperative air leak and chest drainage compared with continuous suction and digital drainage.

A prophylaxis study of acute exacerbation of interstitial pneumonia after lung cancer surgery.

INTRODUCTION: Acute exacerbation of interstitial pneumonia (AE-IP) is a lethal complication after lung surgery. We conducted a prospective, multi-institutional phase II trial to assess the efficacy and safety of prophylactic measures. METHOD: Patients with lung cancer with dorsal subpleural fibrotic changes occupying three or more segments of both lower lobes and planned anatomical lung resection were enrolled. Prior to surgery, patients received a 125-mg bolus injection of methylprednisolone and continuous intravenous infusion of sivelestat sodium hydrate (sivelestat) for 2 days. RESULTS: Sixty-nine patients were analysed. Preoperative high-resolution computed tomography (HRCT) showed 37 (53.6%) cases presented with usual interstitial pneumonia (UIP) and possible UIP pattern. There were 60 lobectomies and 9 segmentectomies. Thirty-eight cases were in clinical stage I. No adverse events associated with prophylaxis were observed. There were four cases of AE-IP (5.8%), higher than the expected 2.0%. Three of the four cases showed inconsistencies with the UIP pattern in preoperative HRCT and were pathologically diagnosed as UIP. All patients died of respiratory failure. Overall, 89.9% were diagnosed as idiopathic interstitial pneumonias; UIP was found in 48 patients (69.6%). Severe post-operative complications occurred in 11.6% of the cases. There were 35 deaths, 17 cases of lung cancer and 11 cases related to interstitial pneumonias. The overall survival rate at 3 years was 41.8% of the total and 47.2% of cases with clinical stage I. CONCLUSIONS: Perioperative use of sivelestat and low-dose methylprednisolone in patients with anatomical lung resection was safe but did not prove to be a prophylactic effect for AE-IP.

Retrospective study of efficacy of adjuvant chemotherapy using tegafur-uracil in patients with non-small cell lung cancer with primary tumor size of 4.1-5.0 cm.

BACKGROUND: The staging of patients with a tumor of diameter 4.1-5.0 cm and no lymphatic/distant metastases have been up-graded to stage IIA in the latest 8th edition of the TNM staging system. However, the efficacy of adjuvant tegafur-uracil (UFT) therapy in these patients, which has been recommended in the guideline issued by The Japan Lung Cancer Society, remains unclear. We evaluated the efficacy of adjuvant UFT therapy among a cohort by retrospective analyses of multicentric database. METHODS: In 2005-2007, 130 patients with p-stage IB non-small cell lung cancer (NSCLC) (diagnosed according to the 7th edition of the TNM staging system) and tumor size of ≥3.1 cm underwent anatomic complete resection at nine of our affiliated hospitals. We retrospectively reviewed the clinicopathological characteristics and the outcomes among these patients. RESULTS: Ninety-eight patients had tumor size of 3.1-4.0 cm (T2a group), whereas 32 patients had tumor size >4.0 cm (T2b group). Overall, patients who received adjuvant UFT showed a tendency of better outcomes than patients who did not [hazard ratio (HR) 0.564; 95% confidence interval (CI), 0.257-1.238, P=0.147]. In subgroup analyses, patients who received adjuvant UFT also tended to show better outcomes than those who did not in both T2a group and T2b group (HR 0.504; 95% CI, 0.202-1.255, P=0.132 in T2a group and HR 0.855; 95% CI, 0.181-4.033, P=0.843 in T2b group, respectively). CONCLUSIONS: Our results suggest that adjuvant UFT therapy have the potential to improve postoperative outcomes even in patients with p-stage IIA disease, as classified according to the 8th edition of the TNM staging system.

Postoperative follow-up strategy based on recurrence dynamics for non-small-cell lung cancer.

OBJECTIVES: Our study was designed to visually represent recurrence patterns after surgery for non-small-cell lung cancer (NSCLC) with the use of event dynamics and to clarify postoperative follow-up methods based on the times of recurrence. METHODS: A total of 829 patients with NSCLC who underwent complete pulmonary resection from 2005 to 2007 in 9 hospitals affiliated with the Yokohama Consortium of Thoracic Surgeons were studied. Event dynamics, based on the hazard rate, were evaluated. Only first events involving the development of distant metastases, local recurrence or both were considered. The effects of sex, histological type, pathological stage and age were studied. RESULTS: The hazard rate curve displayed an initial surge that peaked about 6-8 months after surgery. The next distinct peak was noted at the end of the second year of follow-up. On non-parametric kernel smoothing, the maximum peak was found 6-8 months after surgery in men. In women, the highest peak occurred 22-24 months after surgery, which was about 16 months later than the peak in men. The peak timing of the hazard curve was not affected by histological type, pathological stage or age in either sex. CONCLUSIONS: Our results suggest that the timing of recurrence after surgery for lung cancer is characterized by a bimodal pattern, and the times with the highest risk of recurrence were suggested to differ between men and women. Postoperative follow-up strategies should be based on currently recommended follow-up programmes, take into account the recurrence patterns of lung cancer, and be modified as required to meet the needs of individual patients.

Influence of visceral pleural invasion on survival in completely resected non-small-cell lung cancer.

OBJECTIVES: Although the prognostic implications of visceral pleural invasion (VPI) are well established, it remains controversial whether the extent of VPI affects survival in patients with completely resected non-small-cell lung cancer (NSCLC). In addition, the impact of VPI according to nodal status is unclear. We evaluated the influence of the extent of pleural invasion on survival by analysing a multicentre retrospective database of patients who had undergone surgery for NSCLC. METHODS: We retrospectively reviewed the clinicopathological characteristics and outcomes of 639 patients with NSCLC who underwent anatomic complete resection from 2005 to 2007 at nine hospitals affiliated with the Yokohama Consortium of Thoracic Surgeons. RESULTS: The median follow-up was 65.0 months. The extent of pleural invasion was PL0 in 462 patients, PL1 in 135 and PL2 in 42. The 5-year overall survival rate was significantly higher in patients with PL0 tumours (75.9%) than in those with PL1 (63.6%) or PL2 tumours (54.1%). On subgroup analysis according to nodal status, PL0 was associated with a higher survival rate than that of PL1 or PL2 tumours in patients with N0 or N1 metastasis, but not in those with N2 metastasis. There was no difference between PL1 and PL2 in any subgroup. CONCLUSIONS: Our results suggest that the presence of VPI, rather than the extent, has an impact on postoperative survival in patients with NSCLC who have N0 or N1 metastasis. Because very few previous studies have addressed the effects of VPI in patients with N1 disease, further re-evaluation of the prognostic impact of VPI is necessary in this subgroup of patients.