ASCO GU 2018: Using Grade of Tumor Recurrence After BCG to Guide Further Therapy

San Francisco, CA (UroToday.com) At today’s GU ASCO poster session, Dr. Roger Li from MD Anderson Cancer Center presented findings regarding the use of grade of tumor recurrence after BCG for guiding further therapy. Tumors that recur after BCG therapy are considered to be high risk and patients are often recommended to undergo radical cystectomy. However, the nuances associated with the grade of tumor recurrence after BCG treatment are not well understood. Thus, the objective of the current study was to characterize the pattern of bladder cancer progression and cancer specific survival (CSS) in patients with recurrences dichotomized by low grade versus high grade after intravesical BCG treatment.

For this study, the authors reviewed their institutional bladder cancer database to identify 159 non-muscle invasive bladder cancer (NMIBC) patients who had tumor recurrence after induction BCG with/without maintenance therapy. Among these were 38 (24%) low grade and 121 (76%) high grade tumors. Baseline clinicopathologic characteristics including age, gender, primary tumor grade, stage, size, multiplicity and concurrent CIS were collected and compared between the two groups. The primary endpoint was progression-free survival (PFS), with progression defined as the development of MIBC/distant metastasis. In addition, recurrence-free survival (RFS), high grade RFS, and CSS were also compared. Multivariable analysis was performed using the Cox regression model.

Among these 159 patients, the estimated 5-year PFS was 86.8% (95%CI 73.7 - 95.7%) for patients with low grade recurrence and 66.4% (95%CI 50.8 – 75.3%) for those with high grade recurrence (p = 0.003). Patients whose initial low-grade recurrence on BCG therapy had improved subsequent RFS (5.2 vs high-grade recurrence 2.8 years, p=0.007) and high-grade RFS (9.4 vs high-grade recurrence 3.0 years, p<0.001) compared to high grade recurrence. Furthermore, there was also a CSS benefit for low vs high grade recurrence (4 vs. 2 years, p=0.12), although this was not statistically significant. On univariable analysis, high grade recurrence was associated with PFS (HR 2.44, 95%CI 1.10-5.43), which held up on multivariable analysis (HR 3.62, 95%CI 1.24-10.64). High-grade recurrence was not associated with CSS on univariable or multivariable analysis.

The authors summarized that grade of tumor recurrence after intravesical BCG is an important predictor of bladder cancer progression to muscle invasion. However, patients who have low grade recurrences on BCG still may progress and hence should be carefully counselled on bladder sparing therapy. These results support the GU ASCO definition of BCG-unresponsive disease qualified by high-grade recurrence after BCG treatment.

Speaker: Roger Li, MD Anderson Cancer Center, Houston, TX

Written by: Zachary Klaassen, MD, Urologic Oncology Fellow, University of Toronto, Princess Margaret Cancer Centre, Twitter: @zklaassen_md, at the 2018 American Society of Clinical Oncology Genitourinary (ASCO GU) Cancers Symposium, February 8-10, 2018 - San Francisco, CA