Surgical resection was performed in a total of 149 patients due to lung cancer during the study period. The mean age of the patients was 63 (IQR = 11; range, 22–81), among whom 31 were female and 118 were male. The tumors of 87 patients were located in the right hemithorax, while 62 patients had tumors in the left hemithorax. The median survival of the patients was 12.66 months (minimum 0.17 months, maximum 41.96 months, IQR 15.72). Survival was not different between male and female patients (p = 0.272), and the rate of recurrence was not different between male and female patients (p = 0.580). Age was not different between stages (p = 0.851). The incidence of STAS was not different between the genders (p = 0.673). There were 11 patients who had received chemotherapy before the operation. Mediastinoscopy was performed for mediastinal staging before resection in 6 patients. During the follow-up period, 13 patients (8.72%) died, and recurrence was detected in 4 patients (2.7%).
While the median SUVmax value in STAS-positive patients was 12.3 (IQR, 9.09), it was 11.5 (IQR, 13.24) in STAS-negative patients (p = 0.970).
In the present study, a bronchoscopic biopsy was performed in 60 patients (40.3%) preoperatively, and transthoracic fine needle aspiration biopsy was performed in 60 patients (40.3%). Because a diagnosis could not be obtained through preoperative diagnostic procedures in 29 patients (19.4%), a lung resection was performed in these patients after a perioperative wedge resection with frozen sections was examined.
Age was different between the histological groups, p = 0.041. Age was significantly younger in the carcinoid group (p = 0.023). There were no statistically significant differences in the incidence of STAS between histology groups (p = 0.427).
The patients were also sorted into two groups, as < 60 years old and ≥ 60 years old. There were 49 patients (32.9%) aged < 60 years and 100 patients (67.1%) aged ≥ 60 years in these groups. The incidence of STAS was not different between the two groups (p = 0.227). Likewise, the parietal pleural invasion rate, alveolar–bronchial invasion rate, perineural invasion rate, and visceral pleural invasion rate were not different from each other (p = 0.969, p = 0.725, p = 0.720, and p = 0.195, respectively). However, the lymphovascular invasion rate was different (p = 0.015). Survival was found to be lower in the group ≥ 60 (p = 0.027), but the rate of recurrence was not different (p = 1.000).
A very strong negative correlation was found between age and survey (p = 0.005, r = 0.228). In addition, the incidence of STAS was not different between the histological groups (p = 0.427).
The rates of visceral pleural invasion, parietal pleural invasion, lymphovascular invasion, and perineural invasion were statistically different between the STAS-positive and STAS-negative groups (p < 0.001, p = 0.037, p < 0.001, p = 0.017), while the rates of alveolar–bronchial invasion were not statistically different (p = 0.289).
There were no statistically significant differences in STAS incidence and parietal pleural invasion rates between stages (p = 0.372, p = 0.061). However, the rates of visceral pleural invasion, lymphovascular invasion, perineural invasion, and alveolar–bronchial invasion were different from each other (p = 0.002, p < 0.001, p < 0.001, and p = 0.002, respectively).
The most common visceral pleural invasion was detected as Stage 3A. The most common lymphovascular invasion was detected as Stage 2B and Stage 3A. The most common perineural invasion was detected as Stage 2B and Stage 3A. The stage with the most common alveolar–bronchial invasion was determined to be Stage 3A. There were no differences in STAS rates according to the operation type (p = 0.402).
The recurrence rate, survival, and median tumor size were not different from each other in the STAS-positive and STAS-negative groups (p = 1,000, p = 0.086, p = 0.292, respectively). In addition, no significant cut-off value was found in the groups for tumor size (p = 0.293).
Survival was not different between the groups with and without lymphovascular invasion, parietal pleural invasion, or visceral pleural invasion (p = 0.314). However, survival was different between patients with and without alveolar–bronchial invasion (p = 0.024), with median survival found to be high in patients without invasion. The incidence of recurrence was not different between patients with and without lymphovascular invasion, parietal pleural invasion, visceral pleural invasion, alveolar–bronchial invasion, or perineural invasion (p = 0.360 p = 0.349, p = 0.591, p = 0.360, and p = 1,000, respectively). No correlation was found between tumor size and the survey (p = 0.555).