Long‐term follow‐up of T1 high‐grade bladder cancer after intravesical bacille Calmette‐Guérin treatment

Study Type – Therapy (cohort) Level of Evidence 2b What’s known on the subject? and What does the study add? High‐grade non muscle invasive bladder cancer is a very aggressive disease, potentially lethal if not managed adequately, because of the ability of these tumours to invade surrounding tissues and become metastatic. Treatment with intravesical BCG has been shown to delay progression to muscle invasive or/and metastatic disease, preserve the bladder, and decrease the risk of death from bladder cancer. However, most studies have analyzed patients with short follow‐up, and long‐term data about the real efficacy of BCG to prevent tumour recurrence, progression and impact mortality are lacking. This study has analyzed a large series of patients with high‐grade non muscle invasive bladder cancer treated with intravesical BCG in two University Institutions (Toronto and Rotterdam), with a central pathology review by a very experienced uro‐pathologist. It provides further insight into the long‐term risks of progression of patients harbouring high‐grade T1 bladder cancer treated with BCG, demonstrating that about 30% of patients are at risk of progression and that late progressions even more than 3 years after the initial resection and BCG treatment are rare but not exceptional. OBJECTIVE To report the long‐term results of bacille Calmette‐Guérin (BCG) intravesical therapy in relation to disease progression and recurrence in primary T1 high‐grade (HG) bladder cancer (BC) confirmed by central pathological review. PATIENTS AND METHODS In all, 136 patients from two university centres (Rotterdam, n = 49; Toronto, n = 87) were diagnosed with primary T1HG BC. One experienced uro‐pathologist reviewed all slides, ensuring all cases were indeed HG and that muscle was present in all specimens. Patients were treated with BCG induction (six instillations) after transurethral resection (TUR) of the tumour and followed with cystoscopy and urinary cytology. Predictors for recurrence, progression and survival were assessed with multivariable Cox regression models. RESULTS Mean (range) follow‐up was 6.5 (0.3–21.6) years. There were no significant differences for recurrence ( P = 0.52), progression ( P = 0.35) and disease‐specific survival (DSS) ( P = 0.69) between the two centres. Among the cohort, 47 patients (35%) recurred and 42 (30.9%) progressed with a median time to progression of 2.1 years; 16 (38%) of these progressions occurred ≥3 years after the initial BCG course; 22 (16%) patients who progressed died from BC. Overall, 96 (71%) patients had no evidence of disease at the last follow‐up. Carcinoma in situ was the only independent predictor for recurrence in multivariate analysis ( P = 0.011). No independent predictors were found for progression. CONCLUSIONS Conservative treatment with BCG is a valid option in primary T1HG BC. Nevertheless, the aggressive nature of T1HG BC is evident in the fact that 30% progressed, with a high proportion of these progression events occurring ≥3 years after BCG. Caution should be exercised when relying on the long‐term effects of BCG, and close follow‐up of these patients should not be neglected.

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