Tumor invasion and lymph node metastases are the main causes of death in cervical cancer patients [1] [2]. Currently, the standard treatment for early cervical cancer is primary surgical intervention, which involves radical hysterectomy and pelvic lymph node dissection (PLND)[3]. Previous studies have reported a notable correlation between the number of excised lymph nodes and the disease-free survival rates among node-positive patients with cervical cancer[4]. This suggests that adequate removal of lymph nodes in cervical cancer patients with positive lymph nodes appears to be a critical factor for optimal treatment outcomes. However, there is no definitive evidence indicating that extensive lymphadenectomy in negative lymph nodes of cervical cancer confers a survival advantage. Additionally, lymphadenectomy may develop intraoperative complications including hemorrhage, lymphocyst, and lymphoedema[5]. More importantly, lymph nodes, especially tumor-draining lymph nodes (TDLNs), have been recognized as an essential component in cancer immunology and anti-cancer immunotherapies [6]. In consideration of operative complications and lymph nodes’ clinical potential in anti-cancer immunity, precise identification of lymph node metastases is vital for the management of cervical cancer.
At present, lymph node status can be assessed pre-operatively with MRI, CT, and PET-CT. The mean accuracy of lymph node metastase detection was 86% (MRI) and 81% (CT) respectively[7]. PET-CT examination only improves the accuracy of lymph node metastases with lesions > 10mm[8]. Sentinel lymph node (SLN) biopsy is a more targeted method of assessing the spread of apparent early-stage cervical cancer[9]. However, the false negative rate of SLN biopsy can reach 16.6% due to the limitations of tracing methods and pathological detection techniques [10]. Therefore, we can explore other approaches to improve the detection rate of lymph node metastasis.
Considerating the relationship between TDLN and tumors, we raise a question: whether lymph node metastases can be predicted through tumor-infiltrating immune cells? In 2006, a paper published in Science proposed that evaluating the tumor-infiltrating immune cells is a more accurate indicator of patient survival compared to traditional histopathological techniques[11]. Subsequently, CD8+ T cells and CD57+ NK cells have been shown to provide prognostic values in several human malignancies[12–14]. Among these tumor-infiltrating immune cells, CD8+ T cells are essential in the immune system's resistance to tumor immune response and can directly eliminate tumor cells through their cytotoxic capabilities[15, 16]. Additionally, a variety of stroma cells, such as cancer-associated fibroblasts (CAFs), have also received increasing attention recently[17]. For instance, CAFs can participate in tumor immunosuppression by limiting T cells in the extracellular matrix or affecting the function of CD8+ T cells, thereby promoting tumor lymph node metastases[18, 19]. Therefore, both tumor-infiltrating immune cells and stroma cells have the potential to predict tumor metastases.
In this study, the number of CAFs and tumor-to-stroma CD8+ T cells ratio (CD8+ T cells T:S ratio) in invasive cervical cancer were observed to explore their clinical significance and predictive value for lymph node metastases.