Smokers and ex-smokers who undergo transurethral resection of non-muscle-invasive bladder cancer (NMIBC) are at higher risk for disease recurrence compared with nonsmokers, according to new data.

Researchers led by J. Alfred Witjes, MD, of Radboud University Nijmegen Medical Center in Nijmegen, The Netherlands examined recurrence-free survival (RFS) among 718 patients who underwent transurethral resection of NMIBC. Of these, 597 were current and former smokers and 121 were nonsmokers.

After a mean follow-up of 2.5 years, the investigators identified recurrences in 284 patients (39.6%). RFS was 46.8% among the current and ex-smokers compared with 62.3% for nonsmokers, researchers reported in European Urology (published online ahead of print). The mean time to recurrence was 19.7 months (median: 16.2 months). Nearly 33% of all recurrences occurred in the first year of follow-up.

Using prognostic factor definitions established by the European Organization for Research and Treatment of Cancer, current and ex-smokers had a 47% increased risk of recurrence compared with nonsmokers, They had a 57% increased risk according to prognostic factor definitions established by Club Urológico Español de Tratamiento Oncológico.

The study also confirmed the significance of known risk factors for recurrence, including history of recurrences and number of tumors.

Cigarette smoking is the most well-established risk factor for bladder cancer, and an estimated 60% of all bladder cancers result from smoking, the investigators noted.