In recent years, the incidence of prostate cancer has shown a significant upward trend worldwide (18). Many countries and regions have included PSA screening in routine physical examinations for older men. This will help improve the detection rate of prostate cancer, diagnose and treat of early prostate cancer, especially prostate cancer of clinical significance. Although with the development of RP technology, prostate cancer patients can obtain good tumor control and achieve radical results, there are still some patients who will inevitably experience BCR, or even fail to take appropriate measures in time, leading to the progression of the disease (19, 20). Therefore, how to accurately predict which patients will have BCR has become a major problem for clinicians. The purpose of this study was to examine the predictive value of the PNI for BCR in patients undergoing RARP. PNI combines serum albumin concentration and lymphocyte count. It is a simple and effective objective data assessment system that can objectively reflect the patients’ preoperative nutritional and inflammatory immune status. At the same time, it overcomes the invasiveness risk caused by previous predictive factors, which can be measured with a simple blood test.
Many researchers currently believe that inflammation has a certain relationship with the recurrence and metastasis of tumors (21). Because the uncontrolled persistence of inflammatory responses may lead to severe cell and genome damage, resulting in wanton cell proliferation and genome instability, and increasing the risk of malignant tumors (22). Previous studies have shown that inflammation may be one of the causes of prostate cancer. There may be a certain relationship between prostatitis and the occurrence and development of prostate cancer (23). Among numerous inflammatory cells, lymphocytes play an important role in tumor immune surveillance (24). They can inhibit tumor proliferation and metastasis by promoting cytotoxic cell death and the production of cytokines (7). The reduction of lymphocytes will lead to immune responses. Studies have shown that lymphopenia is an independent prognostic factor for overall and progression-free survival in cancer patients (25–27).
There is also a close relationship between the nutritional status and prognosis of cancer patients (28). Malignant tumor itself is a chronic wasting disease, especially in advanced patients, who often develop cachexia. Malnutrition can also inhibit the function of the immune system to a certain extent, leading to the recurrence and progression of tumors (29). In clinical practice, we usually use serum albumin concentration to evaluate the nutritional status of patients. Low preoperative albumin may affect the enzyme production ability and self-repair ability of tissues and organs, which may lead to a poor prognosis (30). Liu et al. (31) conducted a meta-analysis on 23 studies and found that low preoperative serum albumin levels were associated with poor prognosis of urothelial cancer.
PNI on the prognosis of different tumors has been analyzed in some previous studies. Xu et al. (12) conducted a prognostic analysis on 508 patients after radical breast cancer resection. They found that higher PNI was associated with better disease-free survival (DFS). Kubota et al. (11) analyzed the prognosis of 183 cases of oral cancer and found that higher pre-treatment PNI was associated with better OS, while lower pre-treatment PNI and higher treatment SII were associated with worse DFS. The correlation between many urinary tumors and PNI has also been gradually discovered. Kim et al. (32) showed that the OS and cancer-specific survival rate of renal cell carcinoma patients in the low PNI group were relatively poor. KARSIYAKALI et al. (33) found that PNI can be used to predict tumor stage in patients with primary bladder cancer, and lower PNI level is associated with higher stage disease. In a 2021 study, Li et al. (15) have evaluated the impact of PNI on BCR in patients with RARP. They used a cutoff value of 46.03 to divide 136 patients into a high PNI group and a low PNI group, and Cox proportional hazard analysis confirmed that PNI is an independent prognostic factor for predicting BCR in patients with RARP.
In this study, the optimal cutoff value of PNI was 47.425, then patients were divided into high PNI group and low PNI group. Data analysis confirmed that PNI is an independent prognostic factor for predicting BCR in patients with RARP. Patients with a low level of PNI have a higher rate of BCR after RARP, which is similar to the conclusion of previous studies. This also shows that there is a correlation between the patients’ preoperative nutrition and inflammatory immune status and prognosis. We can take certain intervention measures during the perioperative period to increase the patients’ albumin and lymphocyte levels, thereby improving the treatment effect and long-term prognosis. In addition, we also found that PSA is an independent prognostic factor in predicting BCR in patients with RARP, and PSA levels are positively correlated with the rate of BCR. Thereafter, we established a BCR prediction score model based on PNI and PSA. And its predictive value was confirmed in both the training group and the validation group. In addition, we also constructed a nomogram to predict the probability of BCR in patients with RARP at 6-, 12-, and 24-months after surgery. According to the results of the calibration plots, nomogram performed well in predicting the probability of BCR in 6-, 12-, and 24-months in both the training group and the validation group. So, we can use this model to predict the BCR risk of patients, consequently identifying high-risk patients as early as possible and helping them optimize treatment plans to obtain better survival results.