Bacillus Calmette–Guérin (BCG) has been the standard of care for the treatment of high-risk, non-muscle-invasive bladder cancer (NMIBC) for decades, but 49.6% of high-risk and very-high-risk patients will experience progression to muscle-invasive disease in five years. Furthermore, cytology and cystoscopy entail a high burden for both patients and health care systems due to the need for very long periods of follow-up. Subsequent adjuvant treatment using intravesical immunotherapy with BCG has been shown to be effective in reducing tumor recurrence and progression, but it is not free of severe adverse effects that ultimately diminish patients’ quality of life. Because not all patients benefit from BCG treatment, it is of paramount importance to be able to identify responders and non-responders to BCG as soon as possible in order to offer the best available treatment and prevent unnecessary adverse events. The tumor microenvironment (TME), local immune response, and systemic immune response (both adaptive and innate) seem to play an important role in defining responders, although the way they interact remains unclear. A shift towards a proinflammatory immune response in TME is thought to be related to BCG effectiveness. The aim of this review is to collect the most relevant data available regarding BCG’s mechanism of action, its role in modulating innate and adaptive immune responses and the secretion of certain cytokines, and their potential use as immunological markers of response; the aim is also to identify promising lines of investigation.
卡介苗（BCG）作为高危非肌层浸润性膀胱癌（NMIBC）的标准治疗方案已沿用数十年，但49.6%的高危与极高危患者将在五年内进展为肌层浸润性疾病。此外，由于需要极长期的随访监测，尿脱落细胞学与膀胱镜检查给患者及医疗系统均带来沉重负担。后续采用BCG膀胱灌注免疫治疗的辅助方案虽被证实可有效降低肿瘤复发与进展风险，但其引发的严重不良反应仍会最终损害患者生活质量。鉴于并非所有患者均能从BCG治疗中获益，尽早识别BCG治疗应答者与非应答者至关重要，这有助于提供最优治疗方案并避免不必要的副作用。肿瘤微环境、局部免疫反应及全身性免疫应答（包括适应性免疫与固有免疫）在决定治疗应答方面发挥重要作用，但其相互作用机制尚未明确。目前认为肿瘤微环境向促炎性免疫反应的转变与BCG疗效相关。本综述旨在整合关于BCG作用机制、其在调节固有/适应性免疫应答及特定细胞因子分泌中的作用、以及这些因子作为免疫应答标志物潜力的关键数据，同时探索具有前景的研究方向。
肿瘤(癌症)患者之家