Abstract
Objectives
Lung cancer remains a major health concern in Japan, with over 126,000 cases diagnosed in 2019. Surgery is the primary treatment for stage I–III non-small-cell lung cancer. The 6-min walk test is widely used to assess physical endurance before and after surgery, with preoperative distances below 500 m associated with prolong hospital stays. Postoperatively, endurance typically decreases by 50–100 m. Early mobilization is critical to prevent this decline; however, no clear consensus exists on optimal rehabilitation protocols after lung cancer surgery.
Methods
This retrospective cohort study examined the relationship between early postoperative walking distance and clinical outcomes in 104 patients who underwent lung cancer surgery between 2020 and 2023. Physical function was assessed using the 6-min Walk Test before admission and before discharge.
Results
A significant correlation was found between the distance walked within the first 24 h after surgery and the pre- and postoperative 6-min walk test performance. However, no significant association was observed between early walking distance and length of hospital stay or postoperative complications.
Conclusions
Early mobilization after lung cancer surgery aligns closely with preoperative endurance levels, suggesting that improving preoperative physical function can enhance postoperative recovery and reduce complications. Further research is needed to standardize the rehabilitation protocols.
Keywords: Lung neoplasms, Rehabilitation, Exercise therapy, Walk test, Length of stay
Introduction
Lung cancer remains a major health concern in Japan, with 126,548 cases diagnosed in 2019 and rising incidence and mortality rates [1]. For non-small cell lung cancer (NSCLC) at clinical stages I to III, surgical treatment is recommended when deemed appropriate, particularly up to clinical stage IIa. A meta-analysis of clinical outcomes following lung cancer surgery demonstrated that surgical treatment for stage I–III NSCLC demonstrates better outcomes than conservative treatment [2]
The 6-min Walk Test (6MWT) for physical function is a common measure of overall endurance, regardless of lung cancer surgery [3]. Preoperative distances typically ranges from 450 to 500 m, with values below 500 m linked to longer hospital stays [4, 5]. Postoperative endurance, as assessed by the 6MWT, decreases by 50–100 m on average, even in the absence of complications [4, 6]. Postoperative rehabilitation, including exercise training, can improve endurance, with reported gain of 62.83 m over 12 months [7]. The walking distance in the 6MWT before and after surgery is widely used as an outcome measure for lung cancer treatment.
Traditional postoperative care following thoracic surgery often prolong bed rest in the first few hours or days [8]. However, postoperative immobility is a major risk factor for deviation from enhanced recovery after surgery (ERAS) protocols and prolonged length of stay (LOS) following colorectal surgery [9]. Additionally, immobility is associated with increased morbidity and LOS following lung cancer resection [10]. A study on early postoperative walking observed that patients walked for 8.26 min (54.94 m) after 34.18 h postoperatively [11]. Implementing a protocol for mobilization within 4 h after surgery could shorten the drainage period [12]; however, it could not reduce the rate of minor complications [13]. Moreover, consensus on perioperative rehabilitation treatment is lacking [14, 15], and systematic reviews have not demonstrated the benefits of early mobilization protocols on postoperative outcomes following thoracic surgery owing to poor study quality and conflicting results [16, 17]. Additionally, the relationship between early discharge (shortened length of hospital stay) and 6MWT and postoperative walking distance, which are related to prognostic predictions, is unclear, and reports on 6MWT after surgery are few.
This study aims to clarify the relationship between walking distance within the first 24 h following lung cancer surgery and clinical outcomes. This study will help to clarify the relationship between the timing and content of postoperative walking training and overall endurance at discharge, aiding in the establishment of rehabilitation treatment after lung cancer surgery. We hypothesized that the walking distance within 24 h after surgery is longer when the 6MWT before admission and at discharge is longer, and the LOS is shorter.
Subjects
Study participants
This retrospective cohort study was conducted at a single center. The participant underwent respiratory surgery at a single facility between June 2020 and May 2023 and were referred to the rehabilitation department. Inclusion criteria involved patients diagnosed with lung cancer, such as small cell lung cancer or NSCLC and those who underwent a physical function assessment, including the 6MWT, by a physical therapist on the day of admission, the following day, or before discharge. Exclusion criteria included patients diagnosed with malignant pleural mesothelioma or metastatic lung cancer and those who did not undergo all physical function assessments, including the 6MWT, by a physical therapist on the day of admission, the next day, or before discharge. This Epidemiological Research Ethics Committee of our institution approved this study (approval number E2024-0172).
Methods
Physical function assessment
Physical function was assessed preoperatively on the day of admission or the following day and from the day before discharge to 2 days before discharge. Assessment items included grip strength on both sides (maximum value after two measurements) and 6MWT score. Grip strength was measured for 5 s in a standing position with the shoulder joints slightly externally rotated and the arms hanging down at 0° flexion and extension, without recoil. The 6MWT was performed based on the American Thoracic Society guidelines [18]. In this study, a 30 m walking course with cones was set up for participants to walk back and forth. Assessment items were the distance walked continuously, minimum percutaneous oxygen saturation during the test, percutaneous oxygen saturation at 100 m of walking, and Borg scale (lower limbs and breath) after the test.
Other assessments
Basic data such as sex, age, height, and weight were obtained. Data on diagnosis, stage classification, preoperative chemotherapy, postoperative introduction of home oxygen therapy, and length of hospital stay were collected from medical records. Additionally, information regarding surgical site, procedure type, duration, pain management method (patient-controlled epidural analgesia or intravenous patient-controlled analgesia), postoperative complications, and comorbidities were collected from surgical records.
Postoperative rehabilitation program
Guidelines strongly recommend mobilization within the first 24 h [19]. Early termination of bed rest/immobilization reduces pulmonary complications such as atelectasis, pneumonia, and venous thromboembolism. In our facility, mobilization was initiated by the operating physician and nurse on the morning after surgery; the urinary catheter was removed if the patient could stand and walk with an intravenous stand. Subsequently, a physical therapist visited the patient’s room to conduct walking training. Before initiating walking training, vital signs (such as blood pressure, percutaneous oxygen saturation, and respiratory status) were assessed. During this process, patients wore a chest drain and patient-controlled analgesia. No leakage was observed from the chest drain during quiet breathing; the percutaneous oxygen saturation at rest was 95% or higher; the systolic blood pressure in sitting and standing positions did not decrease by more than 30 mmHg from the supine position; and no discomfort owing to analgesia or orthostatic hypotension was observed. The attending physical therapist determined the walking distance based on the patient’s pain status and vital signs. The cumulative distance walked during the rehabilitation session was evaluated with one lap around the ward considered as 100 m. The initial walking training was conducted on the morning of the following day, regardless of whether the surgery on the previous day was performed in the morning or afternoon, as long as there were no issues regarding patient vital signs.
Statistical analysis
Statistical analyses were performed using IBM SPSS Statistics ver. 27.0. The correlation between walking distance on the day after surgery and each assessment item was examined using Pearson’s correlation coefficient. Unpaired t-tests and chi-squared tests without correction were performed to compare basic information between participants who walked less than 100 m and those who walked 400 m or more. The level of statistical significance was set at less than 5%.
Results
Study participants
During this period, 228 patients were admitted to the Department of Thoracic Surgery and underwent preoperative consultations in the Department of Rehabilitation. Among them, 11 had malignant pleural mesothelioma or metastatic lung tumors and 27 could not undergo preoperative physical function assessments. Postoperative reevaluation before discharge was impossible in 64 patients. After excluding 32 patients with missing data from the 136 patients assessed, 104 patients were analyzed. Figure 1 illustrates the flowchart for participant selection, and Table 1 presents basic information. All surgeries were performed using hybrid video-assisted thoracoscopic surgery. Sivelestat Sodium was administered in all cases with interstitial pneumonia complications.
Fig. 1.
Flowchart of participants
Table 1.
Characteristics of participants
| Variables | All participants (n = 104) |
|---|---|
| Age (years) | 71.7 ± 8.7 |
| Height (cm) | 160.8 ± 9.6 |
| Weight (kg) | 58.6 ± 11.6 |
| BMI | 22.5 ± 3.3 |
| Sex (men/women) | 67/37 |
| Smoking history (Yes/no) | 73/31 |
| Stages of lung cancer (1A/1B/2A/2B/3A/3B/4A/4B) | 64/21/4/3/8/1/2/1 |
| Spirometry (normal/FEV1.0% < 70/FVC < 80/FEV1.0% < 70 and FVC < 80) | 59/34/9/2 |
| % DLco | 72.8 ± 17.3 |
| Preoperative chemotherapy (yes/no) | 20/84 |
| Frailtya (yes/no) | 5/99 |
| Comorbidity | |
| Interstitial pneumonia | 26/78 |
| COPD/asthma | 8/96 |
| Hypertension | 43/61 |
| Diabetes mellitus | 16/88 |
| Coronary artery disease | 18/86 |
| Preoperative brain metastases | 6/98 |
| Malignant tumor, cancer | 35/69 |
| Musculoskeletal disease | 10/94 |
| Operative time (min) | 138.1 ± 56.6 |
| Operating methods | |
| Lobectomy | 57 |
| Segmentectomy | 32 |
| Wedge resection | 15 |
| Others | 0 |
| Laterality and lobe (right/left) | |
| Right upper lobe | 29 |
| Right middle lobe | 9 |
| Right lower lobe | 20 |
| Left upper lobe | 25 |
| Left lower lobe | 21 |
| PCA (PCEA/iv-PCA/none) | 85/17/2 |
| Pain at initiating walking training (numerical rating scale) | 4.1 ± 3.1 |
| Using Sivelestat sodium hydrate (yes/no) | 25/79 |
| Using home oxygen therapy (yes/no) | 1/103 |
| Postoperative drainage (day) | 4.0 ± 2.4 |
| Hospitalization (from operation to enter the hospital) | 8.2 ± 3.3 |
| Complications (yes/no) | 18/86 |
| Pulmonary fistula, prolonged air leaks | 12 |
| Atelecthasis | 1 |
| Pneumonia | 2 |
| Bowel obstruction | 1 |
| Tachycardia, atrial fibrillation | 2 |
| Walking distance at day 1 (m) | 100.2 ± 75.3 |
Mean ± SD
DLco diffusion capacity of lungs for carbon monoxide, PCA patient-controlled analgesia
aA handgrip strength of less than 26 kg for men and less than 18 kg for women as well as a walking speed of less than 1.0 m/s
Relationship between walking distance at day 1 and clinical outcome
Table 2 presents the correlation between walking distance on day 1 after surgery and clinical outcomes, as well as walking distances before and after surgery 6MWT. Significant correlations were found between walking distance on day 1 for the operative time (min), preoperative walking distance (m), and postoperative walking distance (m) (p < 0.05, Table 2). No significant differences were observed in terms of hospitalization (from operation to discharge).
Table 2.
The relationship between walking distance at day 1 and clinical outcome
| Variables | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | |
|---|---|---|---|---|---|---|---|---|---|
| 1 | % DLco | 1 | |||||||
| 2 | Postoperative drainage (day) | − 0.128 | 1 | ||||||
| 3 | Hospitalization (from operation to enter the hospital) | − 0.220* | 0.477** | 1 | |||||
| 4 | Operative time (min) | − 0.740 | 0.750 | 0.312** | 1 | ||||
| 5 | Walk distance at preoperative (m) | 0.410** | − 0.360 | − 0.230* | 0.680 | 1 | |||
| 6 | Walk distance at postoperative (m) | 0.334** | − 0.147 | − 0.380 | 0.690** | 1 | |||
| 7 | Δ Walk distance (m) | − 0.660 | 0.430 | 0.560 | − 0.133 | − 0.326** | 0.460** | 1 | |
| 8 | Walking distance at Day 1 (m) | 0.150 | 0.160 | − 0.147 | − 0.196* | 0.224* | 0.397** | 0.244* | 1 |
Bold values indicate p < 0.05
DLco diffusion capacity of lungs for carbon monoxide
**Significance probability < 1%. *Significance probability < 5%
Comparison of groups walking less than 100 m and more than 100 m on the day after surgery
Based on the mean walking distance at Day 1 (m) on 100 m for all participants, clinical outcomes were compared between groups walking less than 100 m and more than 100 m. The group that walked < 100 m had a significantly shorter walking distance in the 6MWT before and after surgery than the other groups (Table 3). Additionally, hospitalization (from operation to discharge) and days from surgery to measurement at post-operation was significantly longer, diffusion capacity of lungs for carbon monoxide (% DLco) was lower, operative time (min) was longer, and the usage rate of Sivelestat Sodium was higher in the group that walked < 100 m than those that walked > 100 m (Table 4).
Table 3.
Comparison of groups walking less than 100 m and more than 100 m on the day after surgery
| Variables | All participants (n = 104) | 100 m < (n = 38) | 100 m > = (n = 66) | p value | |
|---|---|---|---|---|---|
| Pre-operation | Grip strength (kg) | ||||
| Right side | 27.8 ± 9.3 | 27.7 ± 10.6 | 27.8 ± 8.6 | 0.980 | |
| Left side | 26.7 ± 9.4 | 26.2 ± 10.5 | 26.9 ± 8.9 | 0.708 | |
| 6MWT | |||||
| Walk distance (m) | 466.9 ± 90.2 | 441.7 ± 96.7 | 481.4 ± 83.5 | 0.030 | |
| Borg scale (breath) | 12.3 ± 2.1 | 12.3 ± 2.8 | 12.3 ± 1.5 | 0.935 | |
| Borg scale (lower leg) | 11.6 ± 2.3 | 11.8 ± 3.0 | 11.5 ± 1.7 | 0.638 | |
| Minimum SpO2 | 94.6 ± 2.5 | 94.3 ± 3.0 | 94.8 ± 2.3 | 0.300 | |
| SpO2 at 100 m | 94.9 ± 8.6 | 95.5 ± 1.9 | 94.5 ± 10.8 | 0.573 | |
| Days from surgery to measurement | 6.9 ± 3.4 | 8.4 ± 4.6 | 6.0 ± 2.0 | < 0.001 | |
| Post-operation | Grip strength (kg) | ||||
| Right side | 26.8 ± 9.2 | 26.7 ± 10.4 | 26.9 ± 8.6 | 0.926 | |
| Left side | 25.4 ± 9.0 | 24.9 ± 10.1 | 25.8 ± 8.4 | 0.636 | |
| 6MWT | |||||
| Walk distance (m) | 383.1 ± 96.0 | 343.2 ± 105.9 | 406.1 ± 82.1 | 0.001 | |
| Borg scale (breath) | 13.6 ± 1.7 | 14.0 ± 1.9 | 13.4 ± 1.5 | 0.089 | |
| Borg scale (lower leg) | 11.8 ± 1.7 | 12.0 ± 1.6 | 11.7 ± 1.8 | 0.472 | |
| Minimum SpO2 | 92.3 ± 3.5 | 91.7 ± 3.7 | 92.6 ± 3.3 | 0.182 | |
| SpO2 at 100 m | 94.1 ± 3.2 | 94.2 ± 3.0 | 94.1 ± 3.3 | 0.865 | |
| Δ walk distance in 6MWT (m) | − 83.7 ± 73.5 | − 98.5 ± 76.8 | − 75.3 ± 70.7 | 0.122 | |
| Walking distance at day 1 (m) | 100.2 ± 75.3 | 26.9 ± 24.6 | 142.4 ± 60.9 | < 0.001 | |
Mean ± SD
Bold values indicate p < 0.05
6MWT six-minute walk test, SpO2 saturation of percutaneous oxygen
Table 4.
Comparison of characteristics between walking less than 100 m and more than 100 m on the day after surgery
| Variables | 100 m < (n = 38) | 100 m > = (n = 66) | p value |
|---|---|---|---|
| Age (years) | 73.5 ± 9.5 | 70.7 ± 8.1 | 0.115 |
| Height (cm) | 160.7 ± 10.3 | 161.0 ± 9.3 | 0.856 |
| Weight (kg) | 59.3 ± 14.1 | 58.2 ± 10.1 | 0.638 |
| BMI | 22.7 ± 3.8 | 22.3 ± 3 | 0.630 |
| Sex (men/women) | 27/11 | 40/26 | 0.284 |
| Smoking history (yes/no) | 30/8 | 43/23 | 0.139 |
| Stages of lung cancer (1A/1B/2A/2B/3A/3B/4A/4B) | 20/5/ 3/3/6/0/1/1 | 44/16/1/1/ 2/1/1/0 | 0.060 |
| Spirometry (normal/FEV1.0% < 70/FVC < 80/FEV1.0% < 70 and FVC < 80) | 22/10/5/1 | 37/24/4/1 | 0.509 |
| % DLco | 67.5 ± 17 | 75.8 ± 17 | 0.019 |
| Preoperative chemotherapy (yes/no) | 7/31 | 13/53 | 0.874 |
| Frailtya (yes/no) | 3/35 | 2/64 | 0.307 |
| Comorbidity | |||
| Interstitial pneumonia | 14/ 24 | 12/ 54 | 0.034 |
| COPD/asthma | 5/33 | 3/63 | 0.112 |
| Hypertension | 17/21 | 26/40 | 0.594 |
| Diabetes mellitus | 7/31 | 9/57 | 0.515 |
| Coronary artery disease | 10/28 | 8/58 | 0.065 |
| Preoperative brain metastases | 2/36 | 4/62 | 0.867 |
| Malignant tumor, cancer | 13/25 | 22/44 | 0.927 |
| Musculoskeletal disease | 3/35 | 7/59 | 0.652 |
| Operative time (min) | 152.8 ± 68.5 | 129.7 ± 47.1 | 0.001 |
| Operating methods | 0.753 | ||
| Lobectomy | 22 | 35 | |
| Segmentectomy | 10 | 22 | |
| Wedge resection | 6 | 9 | |
| Laterality and lobe (right/left) | 0.851 | ||
| Right upper lobe | 10 | 19 | |
| Right middle lobe | 2 | 7 | |
| Right lower lobe | 7 | 13 | |
| Left upper lobe | 10 | 15 | |
| Left lower lobe | 9 | 12 | |
| PCA (PCEA/iv-PCA/none) | 28/9/1 | 57/8/1 | 0.272 |
| Pain at initiating walking training (numerical rating scale) | 4.6 ± 3.0 | 3.8 ± 3.1 | 0.112 |
| Using Sivelestat sodium hydrate (yes/no) | 14/24 | 11/55 | 0.020 |
| Using home oxygen therapy (yes/no) | 1/37 | 0/66 | 0.185 |
| Postoperative drainage (day) | 4.2 ± 2.8 | 3.8 ± 2.1 | 0.420 |
| Hospitalization (from operation to enter the hospital) | 9.6 ± 4.6 | 7.4 ± 1.9 | 0.030 |
| Complications (yes/no) | 10/28 | 8/58 | |
| Pulmonary fistula, prolonged air leaks | 5 | 7 | 0.695 |
| Atelecthasis | 1 | 0 | 0.185 |
| Pneumonia | 1 | 1 | 0.690 |
| Bowel obstruction | 1 | 0 | 0.185 |
| Tachycardia, atrial fibrillation | 2 | 0 | 0.057 |
Bold values indicate p < 0.05
PCA patient controlled analgesia, PCEA patient controlled epidural analgesia
aHandgrip strength of less than 26 kg for men and less than 18 kg for women as well as a walking speed of less than 1.0 m/s
Discussion
In this study, walking distance within 24 h postoperatively showed a significant correlation with the preoperative and postoperative 6-min Walk Test distance (6MWD), change in 6MWD, and duration of surgery. However, no significant relationship was discovered with postoperative complications or LOS. In contrast, a comparison of groups walking less than 100 m and > 100 m the day after surgery revealed that the LOS was significantly shorter in the group walking less than 100 m and the usage rate of Sivelestat Sodium was higher. This study represents a novel investigation comparing walking distance immediately after surgery with clinical outcomes and is the first to enable quantitative evaluation of early postoperative mobilization.
A significant correlation was observed between walking 100 m on the first post and the preoperative 6MWD. This finding suggests that patients with lung cancer with sufficient exercise tolerance before surgery are more likely to achieve early mobilization. Perioperative rehabilitation can prevent postoperative complications [20]. For example, maximum oxygen uptake (VO2 max) of > 15 mL/kg/min before surgery is associated with lower mortality rates [21]. Positive correlation between the 6-min Walk Test distance and VO2 max in patients with chronic obstructive pulmonary disease [22], indicating that extending the 6MWD before surgery may lead to an increase in VO2 max and facilitate smoother early postoperative mobilization.
Previous studies on early mobilization have included mobilization within 24 h in the ERAS [10]; however, no reports have used specific distances as milestones. In studies defining early walking as occurring within 24 h, the early walking group had significantly fewer postoperative complications [11]. In our study, the average walking distance on the day after surgery exceeded 100 m; however, no significant difference in postoperative complications was observed between those who walked 100 m and those who did not (p = 0.065). Therefore, achieving a walking distance of 100 m within 24 h postoperatively may be recommended as part of ERAS. However, a correlation was observed between the 100 m walking distance and duration of surgery. Patients unable to walk 100 m within 24 h postoperatively had a significantly higher use of Sivelestat Sodium. At our institution, Sivelestat Sodium is administered in cases with interstitial pneumonia to prevent the deterioration of respiratory function. Therefore, the inability to walk within 24 h after surgery is considered to be due to preoperative interstitial pneumonia and the resulting decline in overall endurance. In addition, the group that started walking after 24 h after surgery had more complications and longer drainage periods. Therefore, walking 100 m within 24 h after surgery should not be treated as a goal, but rather as a predictive index based on the influence of preoperative factors and hospital stay duration.
No studies have reported 6MWD at discharge after lung cancer surgery. In patients with concurrent chronic obstructive pulmonary disease and lung cancer, the 6MWD decreases by approximately 43 m at 1 month after surgery (from 412.0 ± 27.3 preoperatively to 369.0 ± 33.8 m at 1 month) [23]. They reported minimal clinically important difference in 6MWD for patients with lung cancer ranges from 22.0 to 42.0 m [24]. In our study, the average decrease was 83 m, with a significant correlation between the change in 6MWD and pre- and postoperative distances. This finding indicates that early decline in the 6MWD following lung cancer surgery are related to preoperative physical function. However, no significant difference in the change was observed between groups that walked 100 m within 24 h and those that did not, with higher preoperative and postoperative 6MWD in the 100-m walking group. This finding suggests that a decline in physical function can occur even with extended early walking distance.
In this study, the groups were divided based on an average walking distance of 100 m. Few studies have reported average walking distances within 24 h after lung cancer surgery, leaving room for debate regarding the adoption of 100 m as the ERAS criterion. A significant difference is observed in the 5-year survival rates when the preoperative 6-MWD is less than 400 m in patients with NSCLC compared with those with a walking distance of 400 m or more [25]. Furthermore, a linear relationship has been observed between diffusing DLco and oxygen consumption (VO2) up to approximately 70% of VO2max in healthy participants performing incremental exercises [26]. In this study, participants unable to walk 100 m on the first postoperative day also had low DLco values and interstitial pneumonia. Based on evidence that rehabilitation improves exercise tolerance in interstitial lung disease [27], treatment for interstitial pneumonia and maximizing oxygen intake through rehabilitation before surgery may be related to prognosis after lung cancer resection. In our study, the group that walked within 24 h postoperatively had an average walking distance of 400 m, suggesting that walking 100 m could serve as an outcome indicator following lung cancer surgery. In contrast, another report indicated that a group capable of walking for more than 5 min within 1 h after extubation experienced significantly reduced LOS [27], suggesting that initiating mobilization earlier and extending walking distances could further improve clinical outcomes after lung cancer surgery. However, differences in clinical outcomes are recognized only with or without perioperative interventions such as ERAS protocols. This study also observed significant differences in preoperative and postoperative 6-MWD and the 24-h postoperatively. Patients who could not walk 100 m postoperatively exhibited lower pulmonary diffusion capacity, suggesting that preventing postoperative complications following lung cancer surgery is influenced by preoperative exercise tolerance. This finding aligns with that of a meta-analysis showing that combining preoperative respiratory rehabilitation with aerobic exercise can reduce LOS [28]. The clinical significance of this study is that walking 100 m on the first postoperative day is influenced by preoperative physical function (pulmonary diffusion capacity and overall endurance), and insufficient walking ability on the first postoperative day indicates that adequate physical function may not be regained by the time of discharge. This study suggests that preoperative rehabilitation to improve physical function, particularly endurance [29], is crucial for promoting early discharge, and that early postoperative walking training is necessary to prevent declines in physical function after discharge.
The limitations of this study include its retrospective cohort design, which did not clarify the causal relationship between walking distance, LOS, and complications. Additionally, this single-center study included few participants with a preoperative 6MWD below 400 m and it was not an interventional study to determine whether the rehabilitation program reduced LOS or prevented complications. Furthermore, the walking distance on the day after surgery was left to each physical therapist without setting clear criteria; thus, variations in therapist proficiency may have affected the results. Moreover, cases complicated by interstitial pneumonia accounted for a relatively high proportion (25%), exceeding the level reported in our department’s previous study (15%) [30] and in reports from other institutions [31]. Additionally, interstitial pneumonia was more frequently observed in cases where patients were unable to walk 100 m on the day following surgery. These findings suggest that the presence of interstitial pneumonia may influence clinical outcomes based on walking ability, which remains a limitation that cannot be ruled out. In addition, differences in LOS between the two groups resulted in differences in the timing of the postoperative 6MWT. Since physical function improves daily after lung cancer surgery, a difference of more than 1 day may affect physical function. Therefore, the 6MWT walking distance of the group able to walk 100 m on the day after surgery, which had shorter hospital stays, may have been underestimated. Further, differences in hospital stay length and preoperative conditions (such as low %DLco and interstitial pneumonia) could serve as confounding factors, representing a limitation of this retrospective cohort study.
Conclusion
This study examined the relationship between early postoperative walking distance and clinical outcomes in patients who underwent lung cancer surgery. Our results suggest that early postoperative mobilization, specifically walking 100 m within the first 24 h, is an important indicator of physical function and recovery. Patients with better preoperative endurance are more likely to achieve early mobilization, which may lead to improved overall outcomes. Early walking did not reduce postoperative complications or LOS; however, it served as a useful marker for assessing the recovery potential. Preoperative physical fitness plays a key role in postoperative recovery, and rehabilitation programs should focus on enhancing endurance before surgery. Further studies are needed to refine early mobilization protocols and fully understand their impact on clinical outcomes after lung cancer surgery.
Funding
Open Access funding provided by Hiroshima University.
Data availability
The datasets used and analyzed during the current study are available from the corresponding author upon reasonable request.
Declarations
Conflict of interest
The authors have no relevant financial or non-financial interests to disclose in this research.
Footnotes
Publisher's Note
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
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Associated Data
This section collects any data citations, data availability statements, or supplementary materials included in this article.
Data Availability Statement
The datasets used and analyzed during the current study are available from the corresponding author upon reasonable request.