‘BCG-unresponsive’ definition bolstered by study

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Patients with bacillus Calmette-Guérin-unresponsive bladder cancer had worse clinical outcomes than patients who relapsed but did not meet BCG-unresponsive criteria, according to results of a retrospective analysis presented at the 2017 Society of Urologic Oncology annual meeting in Washington.

The findings provide data to bolster the recently coined consensus definition of BCG-unresponsive disease, according to lead investigator Roger Li, MD, urology fellow at the University of Texas MD Anderson Cancer Center, Houston, working with Ashish M. Kamat, MD, and colleagues.

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“We now have a defined group of patients who will no longer benefit from additional BCG and may be enlisted in clinical trials that look at intravesical therapy agents that would spare patients from radical cystectomies,” Dr. Li said in an interview with Urology Times.

The BCG-unresponsive definition arose from the need to better classify patients unlikely to benefit from further intravesical BCG, Dr. Li said, though data were lacking at the time to confirm that the definition represented a group of patients with worse outcomes.

BCG-unresponsive disease includes two subsets: BCG refractory, or those with persistent high-grade disease 6 months after adequate BCG; and BCG relapsing, or those with recurrent high-grade disease after achieving disease-free state at 6 months (Bladder Cancer 2015; 1:29-30; J Clin Oncol 2016; 34:1935-44).

In practice, however, there are two common scenarios where the BCG-unresponsive definition does not apply, Dr. Li said: first, when a patient does not receive adequate BCG prior to recurrence, and second, when relapse occurs 9 months or more after the last BCG instillation.

Accordingly, Dr. Li and colleagues compared outcomes for patients with clearly BCG-unresponsive disease versus those for patients who did not meet the definition.

The analysis included 125 patients who had high-grade cancer recurrence after BCG treatment between 2004 and 2015. Of that group, 92 met the BCG-unresponsive definition, while 33 did not (27 had recurrence after inadequate BCG and six had a relapse 9 months or more after the last instillation).

Next: Worse PFS in unresponsive patients

Worse PFS in unresponsive patients

BCG-unresponsive patients suffered worse relapse-free survival (p<.001), cystectomy-free survival (p=.009), and progression-free survival (p=.060) when compared to non-BCG unresponsive patients, data presented at the SUO meeting show.

The 5-year estimated relapse-free survival was 66.2% for BCG-unresponsive patients versus 89.3% for non-BCG-unresponsive patients, according to the report. Likewise, estimated progression-free survival was worse in the BCG-unresponsive group at 93.5%, compared to 100% in the non-BCG-unresponsive group.

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Notably, only 19% of the BCG-unresponsive patients had successful repeat intravesical treatment with no recurrence, compared to 70% of the non-BCG-unresponsive patients, the data show.

Those findings suggest that when patients fail after adequate BCG treatment, they should no longer be treated with intravesical therapy, according to Dr. Li.

“They should strongly be advised to undergo radical cystectomy if possible, and they should be counseled on the high likelihood of progression if they were to be treated with intravesical therapy,” Dr. Li said.