Investigators who compared low- and high-intensity cystoscopic surveillance for patients with high-risk non-muscle-invasive bladder cancer (NMIBC) found no significant difference between these approaches with respect to disease progression or cancer-related death, according to a presentation at the American Urological Association (AUA) 2020 Virtual Experience.
“In terms of implications, low-intensive surveillance may be a reasonable option for high-risk non-muscle invasive bladder cancer,” said investigator Michael E. Rezaee, MD, of Dartmouth-Hitchcock Medical Center in Lebanon, New Hampshire, who presented study findings during a May 15 AUA press briefing. “However, we really need a trial to assess whether decreasing surveillance frequency in high-risk disease is actually safe.”
AUA guidelines recommend surveillance cystoscopies every 3 to 4 months for the first 2 years, every 6 months for an additional 2 years, and then yearly, Dr Rezaee noted. These recommendations are based on minimal scientific evidence and mostly on expert opinion.
He noted that approximately one-third of patients with high-risk NMIBC undergo fewer surveillance cystoscopies than recommended.
The study included 1542 patients with high-risk NMIBC: 520 (33.7%) who underwent low-intensity surveillance and 1022 (66.3%) who underwent high-intensity surveillance. The investigators defined low- and high-intensity surveillance according to the number of surveillance cystoscopies over 2 years following diagnosis: 1-5 (low intensity) and 6 or more (high intensity).
Patients in the low-intensity group had significant fewer transurethral resections (37 vs 99 per 100 person-years). At 5 years, the percentage of patients with non-invasive and invasive disease who died from bladder cancer did not differ significantly between the low- and high-intensity groups (5.7% vs 8.2% and 10.1% and 9.7%, respectively).
In a subset of patients with non-invasive disease, low-intensity surveillance was associated with a significantly decreased risk of progression to invasive disease or bladder cancer death compared with high-intensity surveillance (19.3% vs 31.3% at 5 years).
“We can’t say that performing less surveillance for high-risk disease can be recommended at this time,” Dr Rezaee said, adding that the study is not the type upon which such a recommendation would be based.
Dr Rezaee and his collaborators published their findings in PLoS One, where they pointed out that “one of the benefits of low-intensity surveillance may be decreasing a patient’s exposure to peri-operative risks and complications associated with repetitive cystoscopy and transurethral resection, including urinary tract infection, hematuria, and anesthesia complications.”
As for why patients with non-invasive disease who underwent low-intensity surveillance had a decreased risk of progression to invasive disease and bladder cancer, Dr Rezaee and colleagues stated in their report, “One would expect that low-intensity surveillance would delay the detection of recurrences and thus should increase the risk of progression to invasive disease (T1 or T2) or bladder cancer death. We found the opposite. Given the observational nature of our data, it is possible that urologists managed certain high-risk NMIBC patients with low-intensity surveillance based on intra-operative and patient characteristics not measured in our study.”
For example, the investigators said they lacked data on tumor size and number of tumors. “Urologists may have followed solitary or small high-risk lesions less intensely compared to multi-focal or larger lesions, resulting in unmeasured additional risk-stratification by urologists,” they wrote. Consequently, patients who underwent low-intensity rather than high-intensity surveillance may have had an inherently lower risk of progression, according to the investigators.
Rezaee ME, Lynch KE, Li Z, et al. The impact of low- versus high-intensity surveillance cystoscopy on surgical care and cancer outcomes in patients with high-risk non-muscle-invasive bladder cancer (NMIBC). Presented at the American Urological Association 2020 Virtual Experience held in May. Abstract PD50-08.
Rezaee ME, Lynch KE, Li Z, et al. The impact of low- versus high-intensity surveillance cystoscopy on surgical care and cancer outcomes in patients with high-risk non-muscle-invasive bladder cancer (NMIBC) [published online March 23, 2020]. PLoS One. doi: 10.1371/journal.pone.0230417