This preliminary clinical study evaluates the safety and initial efficacy of a novel therapy called Plasma-Activated Saline Solution (PASS) for bladder cancer patients. The study involves a one-week course of PASS administered via bladder infusion in five pre-surgical patients, using imaging and pathology analyses to assess tumor shrinkage and cancer cell death, while closely monitoring for any adverse reactions to explore the therapy's future potential.

This study is a prospective, proof-of-concept clinical trial investigating a novel local therapy for bladder cancer. The intervention involves the use of Plasma-Activated Saline Solution (PASS), a liquid infused with reactive oxygen and nitrogen species (RONS) created by exposing standard saline to cold atmospheric plasma. The goal is to leverage the potential of these activated substances to selectively target and kill cancer cells while minimizing damage to healthy bladder tissue.

The study will enroll a small cohort of five adult patients with confirmed bladder cancer who are already scheduled for a radical cystectomy (surgical removal of the bladder). This design allows for a direct assessment of the treatment's effect on the tumor within a short, controlled timeframe before surgery. Participants will receive intravesical (into the bladder) instillations of PASS every other day for one week, with each instillation retained for approximately one hour.

The primary objectives are twofold. First, to evaluate the treatment's efficacy, researchers will quantitatively measure the reduction in tumor volume using MRI scans conducted before and after the 7-day treatment period. Additionally, the surgically removed bladder tissue will be analyzed in the laboratory using immunohistochemistry to look for biological evidence of cancer cell death (apoptosis). Second, the study will rigorously assess safety and tolerability. This includes monitoring for severe, procedure-related adverse events and systematically tracking patient-reported symptoms like urinary pain and urgency using standardized diaries and scales.

As an initial exploratory investigation, this study is not designed to prove definitive clinical efficacy but to gather crucial first-in-human data on the biological activity and safety profile of PASS. The findings will determine whether this innovative approach warrants further development in larger clinical trials. The study will be conducted under strict ethical guidelines with close safety monitoring and full informed consent from all participants.

Inclusion Criteria:

1. Patients with a pathological diagnosis of bladder cancer.
2. Patients scheduled for radical cystectomy, with at least one measurable tumor lesion ≥10 mm in diameter.
3. Age between 18 and 75 years.
4. Treatment-naïve patients who have not received any prior therapy for bladder cancer.

Exclusion Criteria:

1. Presence of severe comorbidities, including but not limited to cardiac disease, severe hepatic or renal insufficiency, uncontrolled hypertension, or diabetes.
2. Active urinary tract infection or a functional bladder capacity of less than 200 mL.
3. History of other malignancies.
4. Pregnancy or lactation.
5. Poor compliance, assessed as unlikely to complete the trial per protocol requirements.
6. Any other condition deemed by the investigator to make the patient unsuitable for study participation.