| Backgroud and Objective:Lung adenocarcinoma and lung squamous cell carcinoma are the most frequent histological subtypes of non-small cell carcinoma, accounting for 50% and 30% of NSCLC cases, respectively. With the increasing control of smoking, lung squamous cell carcinoma is gradually reduced. However, lung adenocarcinoma is increasing year by year. Due to various subtypes and complex biological characteristics, primary lung adenocarcinoma has a very poor prognosis. In this study, we retrospectively analyzed 792 cases of primary lung adenocarcinoma, aiming to improve the knowledge of the pathological subtypes and standard surgical treatment of lung adenocarcinoma and improve the survival rate of lung adenocarcinoma.Methods:A total of 792 cases of primary lung adenocarcinoma who underwent pneumonectomy in Provincial Hospital Affiliated to Shandong University from January 2007 to December 2012 were enrolled and retrospectively analyzed in this study. All these cases underwent lymphadenectomy according to Naruke lymph node maps and pathologically staged according to 2009 IASLC guideline. The data of gender, age, smoking status, size of tumor, surgical procedures, pathological types, differentiation of tumor, lymph node metastasis were collected from clinical databases. All these patients were regularly followed-up by letters or telephones. SPSS 19.0 was used for the statistical analysis. Chi-square was used to study the differences in different groups..Results:In the 792 cases of lung adenocarcinoma, there were 421 males (53.2%) and 371 females (46.7%). The age varied from 30 to 82 years, with the average age of 58.2 years and the median age of 59.8 years. In 111 cases of central-type lung adenocarcinoma, there were 63 males and 48 females, while there were 368 males and 323 females in 681 peripheral-type lung adenocarcinoma. The differences between the two groups did not reach statistical significance (X2=1.718, P=0.118). In 37 cases of<40 years, there were 7 central-type lung adenocarcinoma and 30 peripheral lung adenocarcinoma. Comparatively, the cases of the two different types of lung adenocarcinoma were respectively 49 and 373 in the group of 40-60 years and 45 and 298 in the group of>60 years. Statistical analysis indicated that the age of central-type lung adenocarcinoma is younger than that of peripheral-type lung adenocarcinoma (X2=3.769, P< 0.041). There were 323 (40.8%) smokers and 469 (59.2%) non-smokers. Among the smokers, smoking index was from 100 to 3150 per year. Smokers accounted for 52.8%(58/111) central-type lung adenocarcinoma and 38.9%(265/681) peripheral-type lung adenocarcinoma. The difference between these two groups was statistically significant (X2=7.032, P<0.006). The cases of upper lobe lung adenocarcinoma (right and left upper lobes) was more than the cases of middle lobe lung adenocarcinoma+lower lobe lung adenocarcinoma (X2=12.645, P< 0.001). In 111 cases of central-type lung adenocarcinoma, there were 26 cases of pneumonectomy,65 cases of pulmonary lobectomy, sleeve resection of bronchus,3 cases of sleeve resection of pulmonary artery,3 cases of sleeve resection of bronchus and pulmonary artery,2 cases of resection of partial atrium,1 cases of resection of carina. In 681 cases of peripheral-type lung adenocarcinoma, there were 603 cases of pulmonary lobectomy,2 cases of pulmonary lobectomy and pulmonary arterioplasty, 8 cases of pulmonary segementectomy and 62 cases of wedge-shape excision of lung. Patients with central-type lung adenocarcinoma have a higher possibility to undergo pneumonectomy than patients with peripheral-type lung adenocarcinoma (56.8%vs1.9%,X2=98.850, P< 0.001). Poor differentiation occurred more in central-type than in peripheral-type, while moderate/well differentiation occurred more in peripheral-type that in central-type. The difference in the two groups reached statistical significance (x2=8.371, P=0.002). There were 351 lung adenocarcinoma patients who had lymph node metastasis, including 64 central-type and 287 peripheral-type. Central-type lung adenocarcinoma had higher lymph node metastasis rate than peripheral-type lung adenocarcinoma (57.7% vs 42.1%, X2=24.275, P< 0.001). Lung adenocarcinoma with the size>2.0 cm had higher lymph node metastasis than that with the size≤2.0cm (57.8% vs 13.0% X2=6.446, P=0.017). Middle and poor differentiation lung adenocarcinoma had higher possibility to had lymph node metastasis than well differentiation tumors (X2 =32.338, P<0.01). According to follow-up data, among all these cases,626 patients have complete follow-up data, while 166 patients were lost of follow-up. The overall 1,3 and 5 year survival rate of all the lung adenocarcinoma were 91.8%,52.3% and 22.5%, respectively. The 1,3 and 5 year survival rate of central-type lung adenocarcinoma were 86.9%、46.7% and 17.9%, while the 1,3 and 5 year survival rate of peripheral-type lung adenocarcinoma were 93.5%、56.2% and 24.6%.Conclusion:Primary lung adenocarcinoma has no association with gender. Peripheral-type lung adenocarcinoma is more common than central-type lung adenocarcinoma. Central-type lung adenocarcinoma had higher possibility of lymphatic recurrence. Central-type lung adenocarcinoma is more frequent than peripheral-type when the age of patients is at <40 years. Central-type lung adenocarcinoma has more correlation with smoking than peripheral-type one. Central-type lung adenocarcinoma is more malignant than peripheral-type one. Upper lobe lung adenocarcinoma is the most frequent type. Primary lung adenocarcinoma with poor differentiation and with the size of>2cm has higher possibility of lymph node metastasis. Pulomonary lobectomy and lymphadenectomy are basic operation precedures for primary lung adenocarcinoma. However, extended resection when necessary could improve the survival rate of primary lung adenocarcinoma. |
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