Abstract
BACKGROUND: Non-muscle invasive bladder cancer (NMIBC) is commonly treated with transurethral resection of bladder tumor (TURBT) followed by intravesical chemotherapy and/or Bacillus Calmette-Guérin (BCG) instillations. While these treatments aim to prevent recurrence and progression, the frequency of their administration and associated side effects can substantially impact patients' quality of life (QoL). OBJECTIVES: We aimed to systematically review the impact of intravesical BCG and chemotherapy instillations on QoL in patients with NMIBC, with a specific focus on how instillation frequency influences treatment adherence and withdrawal rates. METHODS: A systematic review was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines. Over 750 abstracts were independently screened by two independent reviewers. Studies published between 2005 and 2024 were included. Data were extracted on demographics, treatment protocols, QoL outcomes, and adherence rates. Risk of bias assessments were undertaken to assess the quality of the studies. RESULTS: A total of 17 studies were selected, comprising 6 qualitative, 8 quantitative, and 3 mixed-methods designs, totaling 20,045 patients. Frequent instillations were associated with increased urinary symptoms (e.g., urgency and dysuria), fatigue, and emotional distress. Withdrawal rates were high (up to 90%) in intensive schedules, particularly during the first year, due to treatment burden and side effects. Studies demonstrated that reduced instillation frequency could preserve treatment efficacy while improving QoL and adherence. CONCLUSIONS: Frequent intravesical instillations can significantly impair QoL, particularly among older patients. While emerging therapies and supportive strategies may help alleviate treatment burden, clinical decision-making must carefully balance QoL with oncologic outcomes. Future research should prioritize personalized approaches that integrate both clinical efficacy and patient-reported outcomes (PROs).