Analysis of clinical prognostic factors in bladder cancer-associated double primary cancer


 Objective: This study aims to explore prognostic factors in bladder cancer-related DPC(double primary cancer). Method: Patients with bladder cancer admitted to the Department of Urology of the First Affiliated Hospital of Guangxi Medical University from November 2012 to October 2019 were screened. They were divided into simple bladder cancer (n = 27) and bladder cancer-related DPC (n = 27). Differences in sex, average age, smoking history, radiotherapy history, intravenous chemotherapy history, SII, NLR, PLR, PNI, and serum tumor markers between the two groups were analyzed. Factors related to prognosis evaluation were determined. Results: Smoking history, radiotherapy history, intravenous chemotherapy history, SII, NLR, PLR, and PNI were significantly different between the simple bladder cancer group and the bladder cancer-related DPC group (P<0.05). No significant difference in serum tumor markers CA153, CA199, CA125, CA242, CA724, and CEA, sex, and average age of onset was found between the two groups (P>0.05). In the univariate analysis, patient type, SII, PLR, NLR, and PNI had significant effects on survival rate (P<0.05). Multivariate analysis showed that the type of patient was an independent factor affecting survival. The survival rate of patients with bladder cancer-related DPC was lower than that of patients with simple bladder cancer (P<0.001). Conclusion: The incidence of DPC associated with bladder cancer is positively correlated with the history of smoking, radiotherapy, and intravenous chemotherapy. Dynamic monitoring of changes in SII, NLR, PLR and PNI after treatment of the first primary cancer is helpful to evaluate the risk of DPC in patients. The prognosis of patients with bladder cancer-related DPC is worse than that of patients with simple bladder cancer.


Introduction
The concept of double primary cancer (DPC) was rst put forward by Billroth [1] . Bladder cancer-related DPC refers to the simultaneous or successive occurrence of primary malignant tumors in the bladder or other organs of the same patients with bladder cancer. and are two kinds of primary cancers with different pathological types. Global literature reports that the incidence of bladder cancer-related DPC accounts for 1.6%-10.7% of bladder cancer cases [2] . The therapeutic effect on patients with bladder cancer has signi cantly improved with the continuous development in clinical diagnosis and treatment technology; the survival time has been gradually prolonged, and the number of cases of recurrent malignant tumors in the urinary system and other systems of the body has gradually increased. The diagnosis and treatment of DPC still have de ciencies due to the diversity of clinical features and the complexity of the pathogenesis of the disease. Second primary cancer in chronological patients with DPC is easily misdiagnosed as metastatic cancer, resulting in delayed treatment; similarly, second primary cancer in patients with metachronous DPC may be misdiagnosed as metastatic or recurrent after treatment, thereby losing the opportunity of radical surgery. Factors affecting the occurrence and prognosis of bladder cancer-related DPC should be explored for precise medical staging and treatment of tumors.
Bladder cancer is a kind of tumor with strong immunogenicity and severe in ammatory reaction [3] .
Cancer is closely related to in ammation. The in ammatory reaction of the body is the initiation of the immune protection mechanism, which is used to resist the invasion of pathogens and participate in the repair of tissues and microenvironment. However, in some special cases, in ammatory reaction can lead to changes in the local microenvironment of the body tissue. For example, in ammatory response after long-term chronic in ammatory stimulation can lead to cancer due to the changed microenvironment.
The same in ammatory response can rely on cytokines produced to promote tumor neovascularization and participate in the occurrence, development, invasion, and metastasis of cancer. Therefore, a variety of blood-related in ammatory markers have been found and applied to evaluate the prognostic risk of patients with cancer [4][5] . In ammatory indices such as neutrophil/lymphocyte ratio (NLR), platelet/lymphocyte ratio (PLR), and systemic immune in ammation index (SII=N*P/L) are prognostic factors used to evaluate many malignant tumors [6][7][8] . However, whether the expression of blood-related in ammatory markers can re ect the progression of bladder cancer remains unknown [9] . Physical nutrition and immunity are also important factors that affect the prognosis of bladder cancer. Onodera [10] proposed that prognostic nutrition index (PNI= serum albumin (g/L)+5×lymphocyte count (×10 9 / L)) can be used to evaluate the prognosis of patients with cancer. Blood-related malignant tumor antigen refers to speci c substances synthesized by cancer cells and can be detected in the blood of patients with cancer. By monitoring malignant tumor antigens, we can indirectly understand the relevant situation of the tumor, judge the patients' condition, and evaluate their prognosis. Ahmadi [11] reported the correlation between some blood-associated malignant tumor antigens and the prognosis of bladder cancer. The diagnosis of bladder cancer-related DPC often depends on imaging and other examinations, and most patients are in the middle and late stages of the disease when the tumor is detected. Whether it can play a role in the early occurrence and prognosis of bladder cancer and bladder cancer-related DPC through simple and easy to measure blood-related in ammatory indices, prognostic nutrition index, serum tumor markers, and so on remains unclear. The present study aimed to conduct a retrospective analysis to explore the occurrence and prognostic factors of bladder cancer-related DPC. Results can deepen our understanding of bladder cancer-related DPC and guide future clinical work. The classical diagnostic criteria established by Warren and Gates [12] were used in this study: (1) any single tumor must be diagnosed as a malignant tumor; (2) the tumor must have its unique pathological morphology; (3) the tumor occurs in different parts or organs; and (4) the tumor should not be metastatic and recurrent.

Exclusion criteria
The following exclusion criteria were used: (1) patients with incomplete case data; (2) patients who died in the perioperative period during surgical treatment of primary malignant tumor; and (3) patients whose pathology could not be classi ed as primary or metastatic tumor.

Source of cases
A total of 1686 patients with bladder cancer diagnosed by operation and pathology were collected from the Department of Urology of the First a liated Hospital of Guangxi Medical University from November 2012 to October 2019. Twenty-seven cases of bladder cancer-related DPC met the diagnostic criteria and had complete clinical data. Twenty-seven cases of simple bladder cancer were categorized in the control group.

Follow-up mode
All patients were followed up through outpatient reexamination and telephone return visit. The follow-up date ended on October 31, 2019.

Statistical analysis
Statistical analysis was carried out by SPSS26.0 software. Rank sum test was used to compare measurement data, and x 2 test was used to compare counting data. A life table method was used to calculate the survival rate. The COX risk proportional regression model was used in multivariate analysis.
Kaplan-Meier method was used to compare survival rate. Values at P < 0.05 indicate statistically signi cant difference.

Comparison Of Clinical Data
3.1 Sex, cause of treatment, average age of onset, family history of malignant tumor, history of smoking, history of radiotherapy, and history of intravenous chemotherapy The history of smoking, radiotherapy, and intravenous chemotherapy were signi cantly different (P<0.05) between the simple bladder cancer group and the bladder cancer-related DPC group. No signi cant difference (P>0.05) in sex and average age of onset was found between the two groups (Table 1). and CEA were found between the two groups ( Table 2). The follow-up time of 54 patients was 0-72 months, and the median survival time was 52.09 months. Twenty-three deaths were recorded, with a total mortality rate of 42.59%. The 1-, 3-, and 5-year survival rates were 80.0%, 56.0%, and 39.0%, respectively (Table 3).  .533, P < 0.001) was an independent factor that affected the survival rate. The risk of death in patients with bladder cancer-related DPC was 9.713 times higher than that in patients with simple bladder cancer (Table 5).

Comparison of survival rates of different Patient type
Comparison of the survival rates of different Patient type showed that the median survival time of patients with bladder cancer-related DPC was 13 months, and that of patients with simple bladder cancer was 65 months; the difference was statistically signi cant (Log Rankc2 = 28.620, P < 0.001). The survival rate of patients with bladder cancer-related DPC was lower than that of patients with simple bladder cancer ( Table 6 and Figure 1).

Discussion
In this study, signi cant differences (P<0.05) in the history of smoking, radiotherapy, and intravenous chemotherapy were found between the simple bladder cancer and the bladder cancer-related DPC. Patient type, SII, NLR, PLR, and PNI had signi cant effects (P<0.05) on survival rate. The survival rate of patients with bladder cancer-related DPC was lower than that of patients with simple bladder cancer (P<0.001).
At present, the cause and mechanism of DPC remain unclear, and no statistical signi cance has been found in the comparison of age and sex of onset. Considering the overall comparison of bladder cancer and its related DPC between the two groups, it may be related to insu cient number of cases. In the present study, the occurrence of DPC may be related to the following factors. (1).Smoking history may be a risk factor for bladder cancer-related DPC. Tabuchi [13] reported that smoking have 59% higher risk of DPC than non-smoking patients with cancer; smoking causes genetic mutations in the body, and tobacco components, such as aromatic amines and tar, are likely to cause cancer. (2).Medical therapeutic factors, such as history of radiotherapy and intravenous chemotherapy, were higher in the bladder cancer-related DPC than those in the simple bladder cancer. A large number of studies have found that patients with malignant tumors develop DPC after radiotherapy [14][15][16] . Radiotherapy and intravenous chemotherapy are routine methods for treatment of malignant tumors; although these methods can kill cancer cells, they can also cause the carcinogenesis of normal cells.
In ammation runs through the occurrence, development, and metastasis of cancer [17][18][19] . (1).Systemic immune in ammation index (SII) is closely related to the in ammation and immune system of the body.
Neutrophils interact with cancer cells by secreting vascular endothelium growth factor(VEGF). Platelets in the in ammatory microenvironment can also secrete VEGF to affect tumor neovascularization and increase the permeability of neovascularization, which is related to the metastasis and spread of cancer cells [20][21]. Mantovani [22] found that lymphocytes in the blood system are important immune cells and can control the proliferation, variation, and metastasis of cancer cells through cellular immunity and humoral immunity. (2).Abnormalities in blood routine indices, such as neutrophil/lymphocytes ratio (NLR), are often found in patients with advanced tumor; this condition is characterized by an increase in the absolute number of neutrophils and a decrease in the absolute number of lymphocytes. Lymphocytes are an important part of the body's immune system. The decrease in the absolute number of lymphocytes indicates the decline of patients' immunity and the ability to resist tumor. Therefore, changes in NLR calculated by neutrophils and lymphocytes can also re ect the immune function of the body and guide the determination of the prognosis of malignant tumors.Bhindi [21] speculated that NLR is the best in ammatory index of blood-related malignant tumor for predicting the prognosis of cystectomy for bladder cancer.Gondo [23] conducted univariate and multivariate analyses of 189 patients with bladder cancer. The results showed that high NLR was signi cantly correlated with poor prognosis and could be an independent risk factor for tumor prognosis. (3).For platelet/lymphocyte rate (PLR), studies have shown that the number of platelets and the absolute value of lymphocytes in patients with bladder cancer are closely related to their condition and prognosis [24][25] . Therefore, by comparing and analyzing PLR calculated using platelets/lymphocytes, we can judge the prognosis of malignant tumors. Zhang [26] studied the prognostic value of PLR in 124 patients with bladder malignant tumors and found that the prognosis of the high-value PLR was worse than that of the low-value PLR. The results of this study show that increases in SII, NLR, and PLR are important clinical features of bladder cancer-related DPC. Dynamic monitoring of SII, NLR, and PLR after treatment of rst primary cancer is helpful to evaluate the risk of DPC in the patients. When the values of SII, NLR, and PLR continue to increase after the treatment of the rst primary cance, the possibility of DPC also increases. The prognosis of the bladder cancer-related DPC was found to be worse than that of the simple bladder cancer.
At present, prognostic nutrition index (PNI) has been widely used to evaluate the prognosis of patients with cancer.Cui [27] analyzed the clinical data of 329 patients with non-muscular invasive bladder cancer and reported that PNI was an independent risk factor for recurrence-free survival; the prognosis of patients with low PNI was worse than that of patients with high PNI. PNI also indicates the nutritional status and immunity of the body. Poor condition of the body will lead to poor prognosis. The results of this study suggest that low PNI is another important clinical feature of bladder cancer-related DPC. Changes in PNI should be monitored dynamically after the treatment of the rst primary cancer. This strategy helps not only evaluating the risk of developing DPC but also on determining the prognosis of patients.
Cox univariate analysis showed that patient type, SII, PLR, NLR, and PNI in uenced the survival rate. Cox multivariate analysis showed that DPC was an independent risk factor for survival. Kaplan-Meier analysis also showed that the survival time of patients with bladder cancer-related DPC was shorter than that of patients with simple bladder cancer. The values of SII, NLR, and PLR were signi cantly higher, whereas the PNI value was signi cantly lower in the bladder cancer-related DPC than those in the simple bladder cancer. In summary, the preoperative values of SII, NLR, PLR, and PNI in patients with bladder cancer-related DPC have important clinical signi cance in evaluating prognosis.
In this study, no signi cant differences in blood-related malignant tumor antigens CA153, CA199, CA125, CA242, CA724, and CEA were found between the simple bladder cancer and the bladder cancer-related DPC. The reason for this may be compared with the overall data of bladder cancer and bladder cancerrelated DPC cases. It may also be related to CA153, CA199, and other malignant tumor antigens that are not speci c to bladder cancer.
We analyzed and summarized factors related to the occurrence and prognosis of bladder cancer-related DPC. Results provide guidance for future clinical work. However, this study has some shortcomings and limitations. First, this study is retrospective and completed in a single institution and has relatively small sample size. Further multicenter, prospective study with large sample size should be conducted to con rm the ndings. Second, SII, NLR, PLR,and PNI were not analyzed by Cox proportional hazard model in the bladder cancer-related DPC due to the limited number of patients.
Our conclusions are as follows. (1). A positive correlation existed between the occurrence of bladder cancer-related DPC and the history of smoking, radiotherapy, and intravenous chemotherapy. (2).
Signi cant differences in preoperative SII, NLR, PLR, and PNI were found between patients with bladder cancer-related DPC and patients with simple bladder cancer. No signi cant difference in traditional tumor markers such as CA153, CA199, CA125, CA242, and CA724 were detected. (3).The prognosis of patients with bladder cancer-related DPC was found to be worse than that of patients with simple bladder cancer. Declarations 1.Ethics approval and consent to participate This paper belongs to clinical retrospective research type, non-basic experimental type, We mainly collect the related indexes of patients' hospitalization examination and analyze them after follow-up, without violating ethics, and get the informed consent of patients.This study was approved and fully supported by the First A liated Hospital of Guangxi Medical University.
2.Consent for publication All authors participating in this article agree to publish.
3.Availability of data and materials We guarantee that the collected data are true and reliable, and they are the true results of patients included in the clinical diagnosis and treatment process.

4.
Competing interests there is no con ict of interest in any aspect.

5.Funding
The National Natural Science Foundation of China (81660424) provides nancial support for our research.
6.Authors' contributions Zhang and Yang made equal contributions in this study, followed up and collected the research data, and wrote the paper after analysis. Mo and Li were responsible for analyzing the rationality of the audit data and participating in the writing of the paper. Cheng, the correspondent author, proposed the overall design of the paper, participated in the writing of the paper, and put forward guiding opinions on the paper, which was nally nalized.