In some NSCLCs, the pleura can be invaded at an early stage, causing cancer cells to break through the pleura and spread to the visceral pleura or parietal pleura, leading to the advanced stage of the primary tumor at a relatively small size. Pleural dissemination was classified as stage IV according to the UICC/AJCC lung cancer stage and had no surgical indication[6]. Computed tomography (CT) can detect most pleural involvement and malignant pleural effusion[11]. However, in the early stage of pleural dissemination, CT may appear false negative, which leads to the surgeon accidentally discovering pleural dissemination during surgery[10].
Lida et al. reported that the median survival time and 5-year survival rate of NSCLC with pleural carcinomatosis and without other metastatic disease were 34 months and 29.3%[12]. Chiang’s study reported that the 5-year survival rate and median survival time were 30.2% and 29.3 months[13]. In this study, the 2-year survival rate was 46.3% (25/54). Although the survival time of NSCLC patients with pleural disseminated which was found during surgery was significantly longer than other stage IV patients[14], the median survival time was merely about 30 months. It is important to find the prognostic factors for predicting the prognosis of patients, but there are no relevant reports yet. In this study, we found that groups with hypertension history, cN1 ~ 2, cII ~ III stage, high level of CA125 had a worse prognosis than groups without hypertension history, cN0, cI stage, low level of CA125, but the difference was not significant. Cardiovascular disease is the leading cause of late morbidity and mortality among cancer survivors, and hypertension is associated with the survival of tumor patients[15]. Zeng et al. reported that complications of hypertension might confer a poor survival for advanced NSCLC patients[16]. In our study, we found that the survival time of patients with hypertension was shorter than that of patients without hypertension, which was also similar to the results of other related reports. cN and cTNM stages are closely related to the prognosis of patients with NSCLC[6]. However, in this study, we enrolled all patients with M1 stage and their pathological stages were stage IV, which resulted in no significant difference between cN and cTNM stages and the prognosis of lung cancer. Our results showed that the survival time of patients with increased expression of tumor-associated antigen CA-125 was shortened, but the difference was not significant in this study. Unfortunately, age, gender, diabetes history, BMI, family history, tumor size, tumor location, cT stage, ALP, LDH, CK, CK-19 and CEA were not associated with lung cancer survival. However, we found that tumor pathological types and serum levels of GGT and CA199 were significantly correlated with the prognosis of NSCLC with pleural dissemination. The 2-year survival rate of adenocarcinoma (51.1%, 24/47) was significantly higher than that of squamous cell carcinoma (14.3%, 1/7), which might be due to the fact that squamous cell carcinoma had few gene mutations and could only be treated with chemotherapy after the operation, which was less effective than targeted therapy after operation for most adenocarcinomas. Although GTT is an indicator of liver function, it has been proved to be related to oxidative stress[17], which may also be related to the occurrence and development of tumors. We were also surprised to find that the survival time of patients with abnormal GTT increase is shorter than that of the normal group, which indicates that GTT was related to the prognosis of NSCLC patients. The tumor marker CA199 is a sensitive marker for pancreatic, gastric and hepatobiliary malignancies. However, it had less report on the correlation with the prognosis of NSCLC. We confirmed that the prognosis of patients with increased serum CA199 levels decreased significantly, which indicated that CA199 might become a prognostic predictor of patients with pleural disseminated NSCLC found during the operation.
Whether a surgeon should perform resection of a primary tumor when the pleural spread is accidentally detected during surgery has also become a hot topic of research. Some doctors believed that NSCLC with pleural dissemination was stage IV, and there was no indication for surgery. The primary tumor could be used as the evaluation standard of postoperative treatment effect. Therefore, surgical resection of the primary tumor was not recommended. Other doctors believed that primary tumor resection during operation reduced tumor burden and prolonged survival time of NSCLC patients. Positive results have been obtained in several studies that suggest prolonged survival after resection of the primary tumor[8–10]. However, in this study, we found that two-year overall survival after lobectomy (75%, 6/8) was significantly higher than patients with pulmonary wedge resection (40.7%, 11/27) and open-close surgery (42.1%, 8/19), but there was no difference between pulmonary wedge resection and without tumor resection. Our result differs from the previous positive results[8–10] in that there was no clear advantage of pulmonary wedge resection for NSCLC with pleural dissemination found during the operation. In further analysis, we found that different surgical methods in NSCLC patients receiving targeted therapy had similar 2-year survival rates (lobectomy was 66.7%, pulmonary wedge resection was 62.5% and open-close surgery was 61.5%). However, the 2-year survival rate of patients receiving chemotherapy after lobectomy (100%, 2/2), pulmonary wedge resection (12.5%, 1/8) and open-close surgery (0, 0/4) were different. These results suggested that primary tumor resection did not have a significant impact on the prognosis of postoperative targeted therapy NSCLC with pleural dissemination patients. However, it improved the prognosis of patients undergoing chemotherapy after surgery, and the prognosis of lobectomy was better than that of pulmonary wedge resection. Due to the limited number of cases we included, additional cases need to be collected for further justification.
Chemotherapy, targeted therapy and immunotherapy are the common treatment methods for M1 stage NSCLC [3]. Since our cases were collected 2 years ago, when immunotherapy was just emerging and costly in China, no patient we included underwent immunotherapy. We performed gene testing on patients with adenocarcinoma. Targeted therapy was preferred if a driver gene mutation was detected. Chemotherapy was given if there was no mutation in adenocarcinoma patients and all squamous cell carcinoma patients. However, some patients with adenocarcinoma did not undergo genetic testing for economic reasons and directly received chemotherapy or abandoned treatment. Our results showed that the 2-year survival rate without treatment was 0 (0/5), 21.4% (3/14) with chemotherapy and 62.9% (22/35) with targeted therapy. It indicated that the survival time of NSCLC patients with pleural dissemination receiving targeted therapy was significantly longer than that of patients receiving chemotherapy, and targeted therapy might be the first choice if the tumor had the driving gene mutations. However, if there were no driver gene mutations, immunotherapy combined with chemotherapy could be tried and better results could be obtained.