Bladder cancer is one of the most common malignancies of the genitourinary system. [1]. Bladder cancer is the seventh most frequently diagnosed malignancy among men and the tenth most common cancer when both sexes are considered [2]. Approximately 70–75% of newly diagnosed patients present with non–muscle-invasive bladder cancer (NMIBC), whereas 25–30% have muscle-invasive disease (MIBC) [3]. The majority of NMIBC cases are managed with curative intent, with a 5-year survival rate of approximately 90% [4]. During follow-up, 15–20% of patients with NMIBC progress to muscle-invasive disease (MIBC), the majority of which consist of high-grade tumors [5].

While the American Joint Committee on Cancer TNM classification remains the cornerstone for prognostic assessment in bladder cancer, a growing number of biomarkers have been introduced to enhance prognostic precision. Lesions confined to the mucosa (Ta), tumors invading the lamina propria (T1), and high-grade carcinoma in situ (Tis) are collectively categorized as NMIBC [6]. This classification represents a critical prognostic indicator and plays a key role in informing clinical management strategies.

Systemic inflammation and nutritional status play a critical role in cancer prognosis. Hematologic markers such as leukocyte indices (including lymphocyte, neutrophil, and monocyte counts), platelet count, hemoglobin level, albumin, C-reactive protein (CRP), and fibrinogen are easily measurable parameters that can provide valuable insight into postoperative outcomes [[7], [8], [9]].

The HALP score is an immunonutritional biomarker used to predict prognosis in patients with malignancies. [10]. The HALP score combines serum hemoglobin, albumin, lymphocyte, and platelet levels, reflecting a patient's overall health condition, nutritional status, and immune response. While platelet and lymphocyte counts serve as indicators of immune function, albumin and hemoglobin levels represent the patient's nutritional state [11]. First introduced by Chen and colleagues for predicting prognosis in gastric cancer, the HALP index is computed as follows: hemoglobin (g/L) × albumin (g/L) × lymphocyte count (/L) divided by the platelet count (/L) [12]. Recently, several studies have reported that this score is effective in predicting survival outcomes in gastric, renal, esophageal, and various other malignancies [[7], [8], [9]].

NMIBC (non-muscle-metastatic bladder cancer) is characterized by a high risk of recurrence and variable progression, requiring lifelong monitoring and individualized risk stratification. While clinicopathological factors such as tumor stage, grade, and carcinoma in situ status are commonly used, they do not fully reflect the biological heterogeneity of the disease. In this context, systemic inflammation and nutritional status may play a critical role in tumor behavior; because chronic inflammation, immune dysregulation, and malnutrition have been associated with tumor recurrence and progression.

The hemoglobin-albumin-lymphocyte-platelet (HALP) score integrates the essential components of both nutritional status and immune function into a single composite index. Unlike other inflammatory markers that primarily reflect immune activity, HALP simultaneously reflects anemia, protein-energy status, and host immune capacity; these factors are particularly important in NMIBC where repeated surgical interventions and chronic mucosal inflammation are common. Moreover, HALP is derived from routine preoperative blood tests. Because of this, it is a practical, inexpensive, and easily applicable biomarker for long-term follow-up.

Considering these factors, we hypothesized that the HALP score could serve as a useful prognostic biomarker to predict relapse and progression in patients with NMIBC.