Effect of Thymosin on Inflammatory Factor Levels, Immune Function, and Quality of Life in Lung Cancer Patients Undergoing Radical Thoracoscopic Surgery.

Purpose: To explore the effect of thymosin on inflammatory factor levels, immune function, and quality of life in patients undergoing radical thoracoscopic lung cancer surgery.
Methods: One hundred and twenty patients admitted to the Surgical Oncology Department of the First Hospital of Jiaxing from January 2018 to January 2019 were randomized into the study group and the control group using the random number table method, with 60 cases in each group. The control group was treated with radical thoracoscopic lung cancer surgery, and the study group was treated with radical thoracoscopic lung cancer surgery combined with thymosin. The clinical efficiency, inflammatory factors, immune function, and quality of life between the two groups of patients were compared.
Results: There was no significant difference between the two groups in terms of pathological stage, tissue type, maximum tumor diameter, and perioperative indicators such as operative time, intraoperative bleeding, pleural drainage, hospital stay, and the number of intraoperative lymph nodes removed. The levels of CD4 (+%), CD8 (+%), CD4+/CD8+, and natural killer cell (NK) (%) were significantly decreased in both groups after treatment, with significantly higher results in the study group than in the control group. The study group had significantly lower serum interleukin-6 (IL-6) levels and higher interleukin-10 (IL-10) levels than the control group. After treatment, patients in the study group had better postoperative physiological status and overall score than the control group. There was no significant difference in postoperative survival and adverse reactions between the two groups.
Conclusion: The use of thymosin treatment in lung cancer patients undergoing radical thoracoscopic surgery significantly improves immune function, mitigates inflammatory response, and enhances the quality of life, which is worthy of clinical application.

1. Introduction

Lung cancer is one of common malignancies with high incidence and mortality, threatening the health and lives of human being [1, 2]. The severity and symptoms and signs are associated with the site of tumorigenesis, pathological type, presence of metastases, and complications [3]. Early symptoms of lung cancer are mild or even insidious. Surgical treatment is the preferred technique that can cure lung cancer and is predominantly available to midstage (stages I-II), stage IIIa, and partially selective stage IIIb lung cancer with only one side of the chest cavity involved [4].

Surgery is categorized into traditional open-heart surgery and thoracoscopic surgery with respect to incision and access route. Traditional open-heart surgery ensures a full exposure of the surgical field for the removal of the tumor lesion and clearance of lymph nodes under direct vision, thereby contributing to the efficiency of radical surgery. However, this method is associated with postoperative incisional pain and pulmonary dysfunction in patients. Thoracoscopic surgery is a new minimally invasive lung cancer resection technique under thoracoscopy, with merits of minor surgical trauma, less bleeding, milder interference with immune function, and faster wound healing. It contributes to maintain the integrity of the thorax and prevent the ribs from being pulled by external forces [5]. It is also well-recognized for early stage lung cancer patients due to the advantages of preservation of patients' lung function and higher tolerance for postoperative radiotherapy [6].

With the rapid development of immunology and molecular genetics, lung cancer has been found to be closely related to the decline of immune function, which necessitates the immunotherapy for treatment [7]. Thymosin is a group of physiologically active peptides secreted by the thymus tissue, which induces T cell differentiation and development, balances the body's immune status, and enhances the T cell response to antigens, thereby strengthening the body's resistance to disease [8]. T lymphocyte subsets CD3+CD4+ and CD3+CD8+ cells are the main indicators of cellular immune function. The levels of peripheral blood T lymphocyte subsets (CD3+CD4+, CD3+CD8+, and CD4+/CD8+) in patients with malignant tumor before and after chemotherapy can be detected to evaluate the immune function of patients and evaluate the prognosis. It has been demonstrated that thymosin increases total T cells and CD4+ T cells and CD4+/CD8+ ratio and enhances cellular immune function [9]. Studies have shown that the treatment of thymosin combined with antitumor traditional Chinese medicine can effectively improve the immune function of the body and the clinical symptoms of patients and minimize the adverse reactions such as liver and kidney dysfunction, nausea and vomiting, leukopenia, rash, anemia, and neurotoxicity [10].

In this study, 120 patients with lung cancer undergoing radical thoracoscopic surgery in the First Hospital of Jiaxing were included to investigate the effects of thymosin on the level of inflammatory factors, immune function, and quality of life to provide a theoretical basis for the use of thymosin in radical thoracoscopic surgery.

2. Materials and Methods

2.1. Baseline Data

One hundred and twenty patients who were hospitalized in the Surgical Oncology Department of the First Hospital of Jiaxing from January 2018 to January 2020 were randomized into the study group and the control group using the random number table method, with 60 cases in each group. Informed consent was obtained from the patients and their families prior to enrollment. The study was approved by the Ethics Committee of the First Hospital of Jiaxing (approval number CL2017-1535). The study was conducted in strict accordance to Declaration of Helsinki.

2.2. Inclusion and Exclusion Criteria

Inclusion criteria were as follows: ASA (American Society of Anesthesiologists) classes I-II [11], aged 45–75 years, weight of 50–80 kg, body mass index (BMI) ≥18 kg/m2 and ≤30 kg/m2, and first time for elective general anesthesia for radical thoracoscopic surgery.

Exclusion criteria were as follows: severe cardiopulmonary disease, such as severe valvular disease, pulmonary artery pressure above 25 mmHg; preoperative psychosis, history of severe dementia, and schizophrenia; coagulation disorders and liver and kidney dysfunction; communication disorder; history of thoracic surgery; and allergies to thymosin.

2.3. Treatment Methods

2.3.1. Control Group

The control group was treated with radical thoracoscopic surgery. After the patient was given general anesthesia in a lateral position, an incision of about 1 cm in length was made between the 7th and 8th ribs in the anterior axillary line, and a thoracoscope was placed into the incision to observe the tumor. An incision of approximately 3 cm in length was made in the upper lobe of the 3rd rib or the lower lobe of the 4th rib in the anterior axillary line of the patient as the primary operating hole, and then, an incision of approximately 1 cm in length was made in the 7-8th intercostal space or the 9th intercostal space in the posterior axillary line as the secondary operating hole. The operation was performed through the gap in the rib cage, without propping up the rib cage. Under thoracoscopic guidance, the operative field was exposed under the aid of the assistant, and a pair of oval forceps was used to reach into the thoracic cavity and retract and secure the lung lobe from the secondary operating hole. The operating surgeon reached into the chest cavity through the main operating hole and performed lobectomy based on the one-way lobectomy concept, without repeatedly moving the lobe during the procedure. Bronchial and vascular sutures were performed using a lumpectomy linear cutting suture, and lung fissures were then treated to complete the surgery.

2.3.2. Study Group

The study group was treated with thymosin (manufactured by Heilongjiang Xiren Pharmaceutical Group Co., Ltd., State Drug Administration H20063310) on top of the control group. Thymosin treatment was applied jointly on the day of surgery via subcutaneous injection at a dose of 10–20 mg, once a day, and 21 d was taken as one cycle for a total of 2 cycles. After the surgery, both groups of patients were treated with 0.9% sodium chloride solution + sufentanil 2 μg/kg for a total of 100 ml, with a loading volume of 2 ml and 2 ml/h continuous infusion for analgesia.

Both groups received postoperative analgesia management and oral analgesics, including oxycodone, acetaminophen oxycodone, and morphine, with the same dose.

2.4. Observation Indicators

2.4.1. Postoperative Pathological Indexes

Postoperative pathological examination was performed to record the pathological stage, pathological type, and maximum tumor diameter.

2.4.2. Perioperative Period Indexes

The perioperative indexes such as operation time, intraoperative bleeding, pleural drainage, hospital stay, and the number of intraoperative lymph nodes removed were recorded for both groups.

2.4.3. Immune Function and Inflammatory Factors

Fasting peripheral venous blood was collected from patients preoperatively and 2 weeks postoperatively and split into 2 tubes. One tube was used to determine the proportion of CD4+, CD8+, and NK cells using flow cytometry (BD FACS Calibur II with Sinul SET software and FSCSSC gating) to calculate the percentages of CD3+, CD4+, CD8+, NK (CDl6+/CD56+), and CD4+/CD8+ values. The other tube was used for the determination of serum levels of interleukin-6 (IL-6) (IL-6 ELISA Kit, Elabscience Biotechnology Co., Ltd., product ID : E-EL-H0102c) and interleukin-10 (IL-10) (IL-10 ELISA Kit, Elabscience Biotechnology Co., Ltd., product ID : E-EL-H0103c) using the enzyme-linked immunosorbent assay (ELISA) method.

2.4.4. Quality of Life

The Chinese version of the Functional Assessment of Cancer Therapy-Lung (FACT-L) scale [12] was used to assess the preoperative and postoperative qualities of life. All patients were surveyed using an inquiry under the guidance of professional physicians and nurses using the Chinese version of the FACT-L scale before and after surgery, from the dimensions of physical function, role function, emotional function, cognitive function, and social function. The higher the score, the better the quality of life.

2.4.5. Comparison of Overall Survival and Adverse Reactions

Patients were followed up every 4 months after surgery for a total of 24 months, and the survival status and incidence of adverse reactions were recorded.

2.5. Statistical Analysis

SPSS 22.0 software was used for data analysis, and GraphPad Prism was used for graphics rendering. The measurement data are expressed as mean ± standard deviation (mean ± SD) and were examined using the paired samples t-test for for intragroup comparison and the independent samples t-test for intergroup comparison. Count data are expressed as rates (n%) and analyzed using the chi-square test. Kaplan–Meier curves were used to plot survival curves. The difference was considered statistically significant at α = 0.05.

3. Results

3.1. Comparison of Baseline Data

There was no significant difference between the two groups in terms of age, gender, BMI, duration of disease, concomitant diseases, and location of lesions (all P > 0.05). The baseline information of the patients in the two groups is given in Table 1.

Table 1

Comparison of general information.

	Control group (n = 60)	Study group (n = 60)	χ 2/t	P
Age (x¯±s, years)	62.24 ± 11.53	64.19 ± 12.68	0.520	0.471
Gender (male/female)	48/12	51/9
BMI (x¯±s, kg/m2)	22.59 ± 3.48	23.95 ± 4.15	1.945	0.054
Course of disease (x¯±s, years)	3.26 ± 1.25	3.57 ± 1.19	1.391	0.167
Complicated illness (n)
Hypertension	41	38	0.333	0.577
Diabetes	26	29	0.302	0.583
Hyperlipidaemia	22	24	0.141	0.707
Lesion location (n)			1.133	0.889
Right superior	16	12
Right middle	11	14
Right inferior	9	8
Left superior	13	15
Left inferior	11	11

3.2. Comparison of Postoperative Pathological Data

Patients in both groups completed the surgery successfully with no intraoperative complications and death. Postoperative pathological results showed that there were 20 patients with stage Ia, 29 patients with stage Ib, and 11 patients with IIa in the control group and 18 patients with stage Ia, 30 patients with stage Ib, and 12 patients with IIa in the study group. The control group had 10 cases of squamous carcinoma, 22 cases of adenocarcinoma, 21 cases of alveolar cell carcinoma, and 7 cases of other types, and the study group had 12 cases of squamous carcinoma, 19 cases of adenocarcinoma, 24 cases of alveolar cell carcinoma, and 5 cases of other types. The maximum tumor diameter was (2.45 ± 0.82) cm in the control group and (2.59 ± 0.97) cm in the study group. There was no significant difference in pathological stage, tissue type, and maximum tumor diameter between the two groups (all P > 0.05), as given in Table 2.

Table 2

Comparison of postoperative pathological data.

	Control group (n = 60)	Study group (n = 60)	χ 2/t	P
Pathological stage (n)			0.166	0.921
Ia	20	18
Ib	29	30
IIa	11	12
Histological type (n)			0.935	0.817
Squamous carcinoma	10	12
Adenocarcinoma	22	19
Alveolar cell carcinoma	21	24
Others	7	5
Greatest tumor diameter (x¯±s, cm)	2.45 ± 0.82	2.59 ± 0.97	0.854	0.395

3.3. Comparison of Perioperative Indicators

No significant differences were found between the two groups in perioperative indicators such as operative time, intraoperative bleeding, pleural drainage, hospital stay, and the number of intraoperative lymph nodes removed (all P > 0.05), as given in Table 3.

Table 3

Comparison of perioperative indicators ().

	Control group (n = 60)	Study group (n = 60)	t	P
Operation time (min)	149.25 ± 40.26	152.29 ± 44.19	0.394	0.694
Perioperative bleeding (mL)	115.26 ± 32.21	123.36 ± 30.59	1.412	0.160
Pleural drainage (mL)	278.39 ± 61.25	286.94 ± 66.28	0.734	0.464
Hospital stays (days)	11.28 ± 3.14	12.28 ± 4.05	1.512	0.133
Number of lymph nodes removed	12.15 ± 4.28	13.06 ± 4.86	1.088	0.279

3.4. Comparison of Immune Function

Before treatment, there were no statistically significant differences in CD4 (+%), CD8 (+%), CD4+/CD8+, and NK (%) between the two groups (all P > 0.05). After treatment, CD4 (+%), CD8 (+%), CD4+/CD8+, and NK (%) were significantly reduced in both groups, with more decrease in the study group than in the control group (all P < 0.05). The immune function indexes of patients in both groups are given in Table 4.

Table 4

Comparison of immune function ().

		Study group (n = 60)	Control group (n = 60)	t	P
CD4 (+%)	Before	37.25 ± 9.26	35.37 ± 9.24	1.113	0.268
	After	34.19 ± 7.29∗	30.58 ± 7.86∗	2.608	0.010
CD8 (+%)	Before	31.74 ± 9.57	31.21 ± 7.92	0.331	0.742
	After	28.58 ± 7.26∗	25.08 ± 7.95∗	2.518	0.013
CD4+/CD8+	Before	1.21 ± 0.29	1.17 ± 0.27	0.782	0.436
	After	1.11 ± 0.32∗	0.86 ± 0.21∗	5.059	<0.001
NK (%)	Before	24.52 ± 4.41	23.98 ± 4.08	0.696	0.488
	After	21.75 ± 4.18∗	18.12 ± 3.82∗	4.966	<0.001

P < 0.05 compared with pretreatment.

3.5. Comparison of Inflammatory Factor Levels

There was no significant difference in serum IL-6 and IL-10 levels between the two groups before treatment (all P > 0.05), and after 7 days of treatment, serum IL-6 levels significantly decreased and IL-10 levels significantly increased in both groups (all P < 0.05). Overall, the study group had significantly lower serum IL-6 levels and significantly higher IL-10 levels than in the control group (all P < 0.05), as shown in Figure 1.

Figure 1

Comparison of inflammatory factor levels. P < 0.001.

3.6. Comparison of Quality of Life

No significant difference was found in all preoperative quality of life scores between the two groups. The postoperative quality of life scores was significantly improved compared with the corresponding values before surgery (all P < 0.05). After treatment, the study group outperformed the control group in terms of physiological status and overall status of lung cancer after surgery (all P < 0.05), as shown in Figure 2.

Figure 2

Comparison of quality of life. P < 0.001.

3.7. Comparison of Overall Survival

The two-year survival rate was 58.33% (35/60) in the control group and 71.67% (43/60) in the study group after 24 months follow-up, which were insignificantly different (log-rank test, P=0.127), as shown in Figure 3.

Figure 3

Comparison of overall survival. HR, hazard ratio; CI, confidence interval.

3.8. Comparison of Adverse Reactions

At 2-year postoperative follow-up, the control group had 2 cases of incisional infection, 1 case of heart failure, and 3 cases of pulmonary infection, with a total adverse reaction rate of 10.00% (6/60), and the study group had 1 case of incisional infection, 1 case of pulmonary atelectasis, and 2 cases of pulmonary infection, with a total adverse reaction rate of 6.67% (4/60). Overall, the two groups presented similar safety profiles, as given in Table 5.

Table 5

Comparison of adverse reactions (n (%)).

	Incision infection	Heart failure	Pulmonary atelectasis	Pulmonary infection	Total adverse reaction
Control group (n = 60)	2 (3.33)	1 (1.67)	0	3 (5.00)	6 (10.00)
Study group (n = 60)	1 (1.67)	0	1 (1.67)	2 (3.33)	4 (6.67)
χ 2					0.436
P					0.509

4. Discussion

Thoracoscopy is a minimally invasive procedure that is preferred for early and middle-stage lung cancer due to its protection on lung function and tolerance to postoperative radiotherapy. Tumorigenesis is strongly associated with immune escape, and immunotherapy enhances the immunity to kill tumor cells [13]. Thymosin is an immunomodulator that promotes T lymphocyte differentiation and maturation and enhances the function of T lymphocyte, which has been applied in the treatment of diseases featuring a low cellular immune function such as malignant tumors and viral infections caused by immune deficiency [14].

CD4+ is expressed by helper T cells and is a receptor for antigen recognition by the Th cell TCR, which plays an important role in determining the immune function of patients [15]. The CD8 molecule, a leukocyte differentiation antigen, is a glycoprotein that exists on the surface of some T cells to facilitate antigen recognition by T cell receptors and is involved in T cell activation signal transduction, also known as a coreceptor of TCR [16]. CD8+ T cells can specifically kill target cells, and CD4+/CD8+ indicates the potent of immune cells in the human organism, and the decrease in the ratio indicates a weakened immune function of the patient [17]. NK cells are the first line of immune protection that nonspecifically and directly kill tumor cells [18]. IL-6 is an inflammatory cytokine (growth factor) that stimulates the immune system to respond to injury and promotes tumorigenesis by stimulating neointimal growth. IL-10 is an anti-inflammatory cytokine that belongs to the IL-10 family and is secreted mainly by monocytes, lymphocytes, and mast cells. It promotes the proliferation and activation of CD8T + cells, enhances antitumor capacity, inhibits the production of proinflammatory cytokines, and reduces tumor growth caused by chronic inflammation [19].

The results of this study showed that treatment with thymosin in patients undergoing thoracoscopic radical surgery significantly attenuated the inflammatory response, improved immune function, and enhanced quality of life. Thymosin was originally used as an immunomodulatory agent in the treatment of chronic hepatitis B and has been confirmed to significantly inhibit migration and invasion of PD-L1 high expressing NSCLC cells via downregulation of the STAT3-MMP2 signaling pathway compared to PD-L1 low expressing NSCLC cells as evidenced by a prior study [20]. Moreover, compared with EGFR-TKI alone, EGFR-TKI combined with thymosin significantly extends progression-free survival and overall survival and does not increase the incidence of adverse events. Results of the meta-analysis demonstrated that thymosin adjuvant chemotherapy increased objective remission and overall response rates and CD4+ and NK cells and decreased thrombocytopenia and CD4+/CD8+ ratio compared to chemotherapy alone [21]. Thymosin, as an immunomodulator, can regulate the immune function of the body, including the production of CD3+, CD8+, and NK cells. Previous research has revealed that thymosin promotes the secretion of lymphokines and induces and promotes the differentiation, maturation, and activation of T lymphocytes and their subpopulations. Moreover, it reduces T lymphocyte apoptosis, regulates CD4+/CD8+, stimulates the proliferation of CD3+ and CD4+ cells, increases the phagocytic activity of NK cells, and further enhances the immune capacity of patients [22]. Oour understanding, the inflammatory response is associated with the development and metastasis of tumors. IL-6 regulates the immune response to infections, injuries, and autoimmune diseases and is also involved in the regulation of tumorigenesis, development, and hematopoiesis [23]. IL-10 is a class of anti-inflammatory factors identified in recent years and can inhibit the activation of the body's antigen-presenting cells and downregulate the activity of T cells and immune response capacity through various pathways, which is closely related to the occurrence of the anti-inflammatory response and tumor immune escape [24]. To date, there is a paucity of evidence on the relationship between thymosin and IL-6 and IL-10, and the mechanism of IL-6 and IL-10 is poorly understood. Presumably, it may be associated with improved immune function and resection of lung cancer lesions, which requires further investigation. The absence of significant differences in the 2-year survival between the two groups in this study might be attributed to the short follow-up period and small sample size. Furthermore, thymosin treatment showed a good safety profile without increasing the incidence of adverse reactions in patients. There are several shortcomings in this study. First, the small number of patients included in this study and the short follow-up period resulted in failure to observe the difference in overall survival between the two groups. Second, thymosin is mainly used in immunodeficient patients, and the preoperative immune function of patients failed to be considered in the grouping of this study. Third, the treatment modality of patients after tumor resection was beyond our control, which might bias our results.

5. Conclusion

In conclusion, the application of thymosin treatment in patients undergoing thoracoscopic radical lung cancer significantly improves patients' immune function, mitigates inflammatory response, and enhances the quality of life, which is worthy of clinical application.